Sailnet Tayana List
The following are messages from the Sailnet
Tayana-list covering over 6 years of discussion about engines, engine problems,
suitability when installed in heavy boats, and engine/prop combinations. The predominant engine is the Perkins 4-108
with limited discussions about Yanmars.
The problem with engine RPM/boat speed/prop
pitch comparisons is that it is mostly anecdotal information. The following factors must be considered:
A)
Adding a larger alternator changes the pulley
size to one with a lesser diameter.
RPM’s will indicate 300 to 600 RPM too high. Most Perkins tachometers are not adjustable
for these changes. Therefore a boat with
the original Perkins tach and a larger alternator will not have accurate RPM
readout.
B)
Different
brand propellers with the same pitch can give dramatically different
performances. Prop brand and model is
important. The original Tayana propellers
do not compare well to an identically sized Michigan propeller.
C)
Boat speed instruments may have a slightly
fouled impeller or not be calibrated accurately. Currents can confuse GPS Speed-over-ground
readings unless two-way runs are done.
D)
Finally, any speed comparison is only a snapshot
of the boat’s bottom fouling conditions on any particular day. Only within the first week after a bottom
painting can this factor be discounted.
Here, and also in the archive article “Props
(from Tayana List).doc”, are lots of information on prop pitch versus boat
speed. Most of it is confusing when
trying to make comparisons among boats of the same type. In order to enhance comparisons, Tayana
owners are asked to provide updated or new data by filling in the chart below
and then sending it to wstrausbaugh@cox.net.
Boat:
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Engine |
Transmission & drive ratio |
Propeller Pitch & Brand |
Instruments calibrated? Y/N Tach & Speed |
Bottom Fouling Clean or ? |
RPM |
Speed |
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Now, the E-mails:
Just to add to the confusion. Que Tal is a
T-37 with a Perkins 4-108 and a Borg Warner transmission with a 1.91 to 1
reduction ratio. Prop is 18" by 9 pitch.
It pushes Que Tal at about 6 knots at 3500 rpm. Red line is 4100. The
formula used by the two prop shops I contacted when shopping for a replacement
(the old prop was cracked) suggested a 16 x 10. When I told them the old one
was 18 x 9 they thought that was in the ballpark and that I should stick with
it if I liked it. The engine shop recommended against over propping in order to
keep the RPM’s down because you don't get the full horsepower out of the engine
if you do. Que Tal does rev up to the red line, but I only get a couple of
additional 10s of a knot. In fact, I think the engine is most efficient at
between 2500 and 3000.
Kent Lewis S/V Que Tal T-37 #165 April 1999
(According to the Perkins
4-108 manual, the engine has a maximum RPM in displacement pleasure boat
installations of 3600 RPM. Max cruise is
listed as 3000 RPM. The above RPM’s seem
high and are probably the result of a new alternator with a smaller pulley –
Wayne Strausbaugh, 2005)
___________________________________________________________________________________________________
Kent and others who responded:
Thanks! Since I started this thread I've been reading it with great interest. I have to admit that I am a little confused, but I guess the old saying "What ever floats (propels) your boat" may apply here. I've tallied up the responses so far and added a few from marine surveys of other Tayana's:
- Yanmar 3qm30 and came with an 18 right hand 13 prop on a 1 1/4 inch
shaft.
- With a Volvo MD3B 36HP, I motor easily 6 to 6.5knots.
1600 to 1800 RPM with a 3 blade Bronze marked Alco 510V 16 X 12:
- T37 with a 4-108. According to my survey the shaft is 1 1/4" and
the Prop is 17RH11, 3 blade.
switched to Autoprop):
- Que Tal is a T-37 with a 4108 and a Borg Warner transmission with a 1.91 reduction
ratio. Prop is 18" by 9 pitch. It
pushes Que Tal at about 6 knots at 3500 rpm. Red line is 4100.
- Sparhawk had a 18 x 12 x1 1/4 RH with Yanmar 3QM30
- From Survey of T-37 thanks to Jim Guin in Florida: Perkins 4-108, 17 x
11 RH
- Nautical Weaver has a Perkins 4-108, Borg Warner 1.9:1, and a 18 x 8 x
1 1/4 RH (re pitched from 18 x 10?) Why, I'm not sure other than he said it was
sluggish.
I have two more questions just
to make sure I understand over propping. It means a bigger prop and/or more
pitch. Right? And more pitch means you will move the boat further at the same
RPM, which translates to more speed at a lower RPM. Right? Which means you may
not reach max RPM before you hit hull speed. Right?
Bottom line is I'm not really any
closer to deciding on what prop I should get. Except I know I don't what an
Autoprop (no offense). Maybe I'll take the advice of Patrick Boulter of
Barnacle Boulter's in Little River SC and stop by there on the way up the coast
to let him put the boat and prop to the test.
Thanks for everyone's input.
Ray Slaninka S/V The Lorna Doone April
1999
___________________________________________________________________________________
Interesting discussions but I think that transmission drive ratio's are needed as well as engines to make comparisons. I have a V-42 with a Perkins 4-108 and a Hurth 150 transmission running a 1.95:1 drive ratio. I repitched the original prop four times, tried a prop of a different brand and have finally changed to an Autoprop. What I have learned probably applies to all heavy cruising boats:
The original factory prop was 18X10
and gave a max speed of 6.3 to 6.5 Kts. Cruise speed was 5.8 at around 2000
RPM. I repitched it 3 times from 18X10 to 17 1/2X11 (no change in performance),
17X12 (picked up a few tenths of a knot and lost a bit of "thrust" at
low speed), & finally 16X13. The smaller prop is a "speed" prop.
That is, it is optimized for speed in calm water. Speed went to 5.8 at 1800 RPM
with about 6.3 Kts at 2000. Top speed was 7.6 Kts but the engine would
immediately start to increase engine water temp. Seven knots was sustainable at
2300 RPM. Low-end thrust suffered
greatly with the small prop.
Acceleration was cut in half and the boat had a hard time maintaining speed
with any wave action on the bow.
Moderate pitching (3 to 5 feet) resulted in 4 knots or less. But the boat cruised well in the ICW. The bottom line here is that a smaller prop
with more pitch equals better speed but less thrust. I tried another brand of 3-blade prop (maybe
a Michigan?) with a pitch of 16X13 but it had a slightly different shaping of
the blades and the engine could hardly pull 2000 RPM. It was lugging severely. I repitched it to 16X12 and it was
satisfactory but never equaled the performance of the Taiwan prop. The Tayana
prop had wider and thicker blades.
Then I got an Autoprop. The Autoprop
was easy to install on a V-42. It is a 18 1/4 inch prop. I simply dove under
the boat, placed it on the shaft and tightened the nut. Speeds are now 6.3 at
1800 and 6.6 at 2000 RPM. The engine only has to produce 75 to 80% of it's
previous horsepower to achieve RPM and fuel savings are at least 20%. The
engine never labors. Max RPM is 3600 when stopped and 2800 at 7 knots. Top
speed is 7.8 knots but it still runs warm when exceeding hull speed. Thrust and
acceleration are better than any previous prop I have tried. Using almost full speed in reverse, the boat
has stopped in 50 feet from 5 1/2 knots! Head seas are no longer a problem. Any
loss of speed from pitching immediately results in the prop repitching and
speed being recovered quickly. Lots of thrust is available when needed. But the
biggest test was when I took another V-42 in tow and made 5.8 knots at 2300 RPM
with only a 5-degree rise in engine temp (on a 95-degree day in warm water!). Yeah, with TWO V-42’s! The Autoprop is
both a "speed" prop and a "power" or "high
thrust" prop. It is reportedly considerably faster than a MaxProp. It is
also expensive. But if an owner thinks that his boat requires a larger engine
and would also appreciate a 20% increase in fuel range, this type of prop could
prove to be a reasonable and money-saving alternative.
Wayne Strausbaugh V-42 C/C RESTLESS April 1999
___________________________________________________________________________________
Note: check the Tayana-list Archives,
"Props.rtf or htm", for a detailed discussion of prop
pitch-versus-speed. Messages concerning
that subject will only be repeated here when other engine information/issues
are included.
___________________________________________________________________________________
Last week I had to replace the fresh water coolant pump on my Perkins 4-108 so I started looking for a parts source with a reasonable price. I found two:
Trans-Atlantic Diesel, White Marsh, VA, (804) 642-9296
Coastal Diesel, New Bern, NC, (800) 682-8809 or (252) 633-2025
They both quoted around $98 for a new pump (part # ) but Trans-Atlantic Diesel had rebuilt ones for $57. I didn't think anything on a Perkins cost under $100 so was rather pleased. Now, I didn't look further so I'll just throw these prices up on the "list" for comparison. If anyone has a better source, please let me know. If we all compare prices, maybe we may locate a really good dealer. I don't mind mail order. It's about as fast as ordering locally anyway.
One thing I did find was that Trans-Atlantic Diesel rebuilt Perkins engines as a specialty and had ten rebuilt 4-108 engines in stock at $5500 each. A short-block overhaul is $3400. They indicated that they always used new marine add-on parts such as heat exchangers and pumps plus they supplied new starters. Sounded like a good source to me. They said they buy direct from England on some items like the Bowman heat exchanger found on the "New 4-108M" (that's what the manual calls my 1982 Perkins). It lists at $2000 and they sell it for $1250. I tried Coastal Diesel to check this out and they quoted $2000 list and $1811 at discount. It's obvious that direct purchase can save big bucks.
Wayne Strausbaugh V-42 C/C RESTLESS May 1999
___________________________________________________________________________________
Subject: Bleeding the Fuel System on a Perkins 4-108
A Caution on invalid bleeding procedures in the Perkins manual:
Watch out for the owners manual on older Perkins engines where it recommends placing a piece of cardboard over the air intake while cranking the engine to start it after bleeding. They wrote the manual prior to the wide spread use of water-lift mufflers. After a minute or two, the water-lift muffler will fill up and then the water overflows into the cylinders. Been there - done that! The engine gets a hydraulic lock and it is tough to get the water out. It won't turn over. If you catch it right away - no problem. Didn't hurt my engine. If you must crank it over for longer than 30 seconds, open the drain on the water-lift muffler and then try again. I wrote Perkins and they actually changed the later manuals...
Also, a mechanic showed me a trick on
how to change the final fuel filter on a Perkins without bleeding the engine.
Back off the fitting at the final fuel filter on the output side to the engine
and pump the filter full. Hold a rag over the fitting to catch the fuel. Then
start the engine, still holding the rag over the fitting to catch the fuel that
comes out. When it stops spitting air, tighten the fitting. Messy, probably not
a recommended procedure, but it works. It also helps to have a shutoff valve in
the fuel lines on the output side of the RACOR so you can change that filter
without draining back the fuel upstream of it.
Wayne Strausbaugh V-42 C/C RESTLESS August 1999
___________________________________________________________________________________
Just an incidental comment ..... If your engine is not spinning near the top rpm due to a too large of pitch or diameter, the engine will not be able to develop sufficient horsepower; hence, poor performance and low boat speed. Check with the engine manual for "max" rpm and compare that with your actual "under load" rpm. (A diesel that is not operating near max rpm at full load is subject to extreme cylinder pressure causing premature wear, blown head gaskets, etc.) If there is a great difference, consider a less pitched prop or have it re-worked. :-)
Rich Hampel - still a Tayana (MKII) Wannabe. September 1999
___________________________________________________________________________________
Subject: Engine lift & removal on a center cockpit V-42
I have a newly acquired '82 V-42
still on the hard in Superior WI. I am
in the process of a large-scale refinish and refit, including an engine
overhaul. One of the worst things that some sailboats can have is a previous
owner.
I have the engine now setting on the
sole of the main cabin, ready to lift out of the companionway. I decided not to
try to remove the cockpit sole because of difficulty removing the partition
panels in the head area. On my boat these panels have been tiled and are
impossible to remove. I elected to lift the engine, move it over and set it
down on the passageway sole and remove the manifold, transmission, bell
housing, flywheel and back plate. All this stuff has to be removed for overhaul
anyway. It was then skinny enough to go through the passage doorway. A friend
and I did this just yesterday but did not have time to actually lift it out
onto the deck. Next weekend for sure. The lifting and moving gantry I made
myself of welded rectangular steel tubing and a boat trailer winch. I was very
pleased with the way it worked.
Anyway, I do need to do something
about a prop and have almost convinced myself to spend the money for a real
one. I look forward with a lot of trepidation to maneuvering this ship in tight
quarters and having next to no experience in handling such a vessel I will need
all the help I can get. Aside from the performance under way, I think the Auto
is called for.
Thanks and fair winds, Merv October 1999
___________________________________________________________________________________
Concerning the advice that a diesel should turn near max RPM, I would like to add some reservations to that.
1) RPM range is dictated primarily by the transmission drive ratio. Some boats have 2:1 ratios like the Hurth transmission and others have basically 3:1 ratios. The first will run much lower RPM’s at cruise speeds (1800 to 2200 RPM) while the second is designed for RPM’s about 500 higher at cruise.
2) A boat with a 2:1 transmission ratio should
never achieve max RPM or anywhere near it. As an example, I have a V-42 with a
Perkins 4-108, a
3) The Autoprop is computer designed for
each boat based on horsepower, transmission drive ratio, hull design, and
displacement. Mine does everything it is supposed to do and appears properly
sized. It will only turn 2600 RPM at my max speed of 7.8 knots at full power.
When the boat is stopped, it will turn 3600 RPM since it uses a much lower
pitch when it senses horsepower applied but no water flowing over the
prop. These RPM’s reflect pretty close
to optimum conditions for this engine/transmission combination and should apply
to a T-37 as well.
Wayne Strausbaugh V-42 C/C
RESTLESS October 1999
___________________________________________________________________________________
Wayne,
I must respectively disagree. An
engine produces its maximum horsepower at a given RPM (and its max torque at a
given, though usually different, RPM).
If the engine can't reach that RPM, then you will not get maximum
power. In order to allow an engine to
reach its max RPM, and thus assure it being able to reach its max power, the
transmission ratios and the prop must be properly balanced with respect to each
other and the engine.
Given that all three (engine,
transmission and prop) are important, and given that of the three, the prop is
by far the easiest and cheapest to replace, it is usually the one that gets
swapped around to try to achieve max RPM.
The mere fact that a boat will reach
its theoretical hull speed at a low RPM in most situations does not mean that
the prop is properly sized and pitched. In fact, it probably means that it is
either too large or too radically pitched which would result in it bogging the
engine down at higher RPM’s. The real test is will the engine be able to
develop its full HP in severe conditions when it is being asked to punch thru
big waves and/or high winds.
I have also had mechanics tell me
that routinely lugging an engine is harmful. Lugging occurs when it is maxed
out under the load it is being ask to carry such that it cannot rev higher.
Allowing it to reach its max RPM will assure that it can get to the peak of the
power curve.
For those reasons, put me down in the
max RPM camp.
Kent S/V Que Tal T-37 October 1999
___________________________________________________________________________________
Bruce, Kent and Wayne,
Is the max power output at a defined RPM also the most efficient level of operation of the Perkins or Yanmar engines? The other issue that I would find helpful in following this discussion would be and efficiency curve of power utilization to speed through the water with different props, but somehow corrected for transmission. (And with a relatively constant loading of displacement). What is RPM for the max power output of the Perkins 4-108? Is it advisable to run it at that level for all day runs? I would assume that with higher speeds (?closer to "hull speed"?), the energy input required increase non-linearly, due to frictional forces, hull resistance, prop inefficiency at higher RPM’s, etc.
The point about not lugging an engine
is something that I have also been taught since I was a boy. But what is that
point in RPM relative to load. Is it a measure of how much the engine RPM is
retarded in percentage when a given load is imposed on it? How does that relate
to the optimal idling speed? On the Perkins, I find that it sets to a smooth
idle at about 900 RPM. When in gear, I find that about 1,000 RPM is the point
at which the engine doesn't increase vibration but allows me to motor slowly in
the anchorage. But what factors should I be attending to?
regards,
___________________________________________________________________________________
You darned scientists make everything
so complicated.
I've never actually seen the power curve for a
4108, but the good people an Admiralty Marine told me it peaked at about 3500
RPM. I have no idea if that is the most efficient engine speed in terms of
miles per gallon, but I suspect that that a lot of other variables enter in to
it. As you mentioned earlier, things like load, how smooth the bottom is, and
sea state will effect it. I suspect each of us is going to have to find out by
trial and error on own boats. Given all those variables, I'm not sure how valuable
a generalized efficiency curve would be, even if one exists.
As for running it all day at the top
of the power curve (not max RPM) , that should be no problem, assuming a
basically sound engine and drive train.
Diesels like to work. The problem is can the crew stand the noise.
Sailors want to hear the wind in the rigging, not an engine and these 37s are
not exactly sound proofed.
I assume your assumption about the
non-linearairity (is that a word?) of energy output is correct.
My seat of the pants approach is to
find a speed where both the engine and I feel comfortable. This summer, plowing
dead into the wind and waves, the engine and I settled on about 2500 RPM.
Coming back two weeks later in a dead calm 2800 seemed about right. In that
case fuel efficiency was greater coming back, but we also had the current with
us so I don't put too much stock in that fact.
A poor answer to your question. Maybe
someone else can do better.
Kent Lewis S/V Que Tal T-37 #165 October 1999
___________________________________________________________________________________
Agree completely with Wayne (? - you must be agreeing with
Thou shalt not have an engine with
excessive combustion chamber pressure ... for very long!
Rx: spin the engine between 80% and
90% of max rated rpm. This has been the engineering "rule-of-thumb"
for almost all reciprocating engines for almost 100 years. :-)
Rich Hampel October 1999
__________________________________________________________________________________
Rich,
I'm not sure we disagree and I'm
sorry if my answer was not clear. I did not mean to suggest that you should
routinely run at max RPM. The point I was trying to make is that you should be
able to run at max power.
If by "spin the engine between
80% and 90% of max rated rpm" you mean that is about as fast as you want
to run it for any extended length of time, I would agree. But that is
contingent on not lugging it at that speed. By using a prop that will permit
the engine to reach it's max RPM, you allow it to easily reach the magic 80 -
90% without lugging. Sizing the prop so it can only get to the lower RPM, even
at full throttle, is by definition lugging it with all the bad consequences you
describe.
According to the local Perkins repair
shop the max RPM for the 4-108 is 4100. 80-90% of that is 3280 - 3690. Since
the peak of the power curve is about 3500, sizing the prop to allow the engine
to reach max RPM means you can easily and safely run at it's highest power
output without lugging it.
Kent S/V Que Tal October 1999
___________________________________________________________________________________
Does anyone have the max rated RPM for the Yanmar 3QM?
Paul,
It has taken awhile but I finally got
a chance to check my service manual. The
continuous rating output is 30 HP / 2600 RPM. The one hour rating is 33 HP /
2800 RPM. Hope this helps.
Bruce October 1999
___________________________________________________________________________________
Well, we have an interesting discussion going here on engine RPM's and props. But let’s look at some technical data on the Perkins 4-108 rather than have to rely on the local mechanic. From a performance chart for the 4-108:
Max torque 78 lbf. ft. (lbf. ft is how Perkins labels it - foot pounds?) at
2300 RPM.
Torque at other RPM's:
1600 – 71
1800 – 75
2000 – 76
2200 - 77.5
2600 – 77
3000 – 74
3600 – 69
Notice that the 1800 to 2200 RPM range used by most boats with a 2:1 transmission ratio is within 3 lbf. ft. of maximum torque.
Max RPM in displacement pleasure boat installation: 3600 RPM.
Max cruise RPM: 3000 RPM.
Net shaft horsepower is 47 at 4000 RPM and 45 1/2 at 3600.
The Perkins performance chart and the Perkins advertisement sheet that it came
from are now posted on the FTP site as well as below.
Back to the discussion. I still disagree
with the statement that "a boat does not have the optimum prop setup if it
cannot reach max RPM at full power".
I have never seen an engine with a fixed, 3-bladed prop that would even
come close to 3600 RPM with a 2:1 transmission ratio. Not that I have seen that many, but I really
have asked this specific question of owners of boats of various kinds. Note the response from Willi Robles. He gets 3150 RPM out of the 3400 max RPM
allowed on his engine with a 3:1 transmission. This is pretty much what I would
expect from that transmission ratio. I
do believe that if a V-42 or T-37 can cruise between 1800 and 2100 RPM and get
6.5 Kts then this is pretty much "as good as gets". This would mean 7 to 7 1/2 Kts at full power
(2600 to 2800 RPM's) although I would expect increased engine temps when trying
to sustain over 7 Kts. Sure it would be nice to have a prop that would allow
the engine to rev throughout the complete power range of the engine. But unless you have an Autoprop, I don't
think that this is realistically achievable. The compromise is the prop/
engine/ transmission setup selected by the engineers at Tayana. For those who want to run in the higher RPM
range, a 3:1 transmission and matching prop should fill the bill. But let’s collect some more data... If anyone
with a 2:1 transmission ratio can achieve anywhere close to 3600 RPM with their
engine, please give us the details and your opinion of whether your boat is
optimized as far as the prop goes.
Wayne Strausbaugh V-42 C/C RESTLESS October 1999
(Go to ftp://tognews.com/Perkins_4-108_PerformanceSpecs and check the files on specifications and
performance curves of the Perkins 4-108)
___________________________________________________________________________________
Having the correct pitch allows the engine cylinder pressure to be a minimum relative value for the horsepower developed.
For instance (as extreme
examples), if too low a pitch: lower rpm developed; hence lower horsepower....
and extremely high cylinder pressure ('lugging' ) , blown head gaskets, bent
piston connecting rods, hammered main shaft bearings, excessive engine wear,
etc.
If too high a pitch:
cavitating/eroding prop , scored cylinder walls, 'hammered' injectors and valve
seats, excessive engine wear.
Most 'steady state'
reciprocating engines 'like' to be run (long term) at near 75% of max developed
horsepower and at the 75% peak of their 'power curve'.
I like to select pitch so that
I get 75% optimum rpm/horsepower output at the rated hull speed of the boat.
Ever since Drs. Otto and Diesel invented their engines, the value for long life
vs.maximum output has been around 75% rpm/horsepower output.
Look at the power curve
'optimum' value in your engine manual, match/record/correct that value near the
hull speed of the boat and you optimize the whole system for economy,
reliability, long life, and extra power 'bursts' when you need it. For me its
like religion, politics, taking risks, etc.; ... I like to be in the 'middle'.
The auto-prop tends to automatically
adjust for the 'optimum' all along the engine power curve. (I just think they
are outrageously expensive, as I can almost do a whole engine rebuild for the
price of an auto-prop.)
___________________________________________________________________________________
The factory told me that if the pitch did not allow close to full rpm, it was overloading the engine, which could have negative implications over time. Did I read your comment right? Is there a difference in these two approaches?
David / Hegira March 2000
___________________________________________________________________________________
Yes, you have it right.........
! If you were underpitched, you would
never reach full rpm.
Rich Hampel T-37 March 2000
___________________________________________________________________________________
My Perkins has used a quart of oil every 12 to 16 hours since new in 1982. The engine has run perfectly for over 6000 hours. I just keep it full, change it every 100 hours and don't worry about it.
Wayne Strausbaugh V-42 C/C RESTLESS July 2000
___________________________________________________________________________________
I had the cylinders of my Perkins fill up with water once with the exact same symptoms. Like you (Rich Hampel), I caught it right away. To get the water out, I drained the waterlift muffler, then "rocked" the engine back and forth with a large socket wrench on the huge bolt of the lower engine pulley. This opened and closed the exhaust valve a tiny bit each time. I then started the engine, heated the oil, changed the oil twice more (running it for a half-hour each time), and everything was fine for the last 3000 hours of engine time. But consider doing an oil analysis after the final oil change to ensure that no water is present. I now have an oil analysis done every 100 hours!
To remove water, pulling the injectors is probably a better idea but if something keeps you from starting the engine within an hour or two of ingesting water, you might incur damage. Reinstalling an injector can be intimidating and can cause further problems since bleeding is required on some engines. Plus, sometimes a new copper washer is required to seal the injector. Do you carry spares? I didn't...
Rather than turn off the water intake, I prefer to drain the waterlift muffler after every 30 seconds of starting if there is a starting problem. Mine has an easily accessible plug. If you want a useful project, drain your waterlift and then measure the water. Try to figure out how much more would be needed to cause a potential backflow problem. Then crank the engine for 30 seconds (with the waterlift empty and the shutdown switch pulled) to see how much water goes in the muffler. Measure again. Then you would know about how long you could crank the starter without having another backflow problem.
Another hint to those who own engines without a decompression lever. You can put a piece of stiff cardboard over the air intake if you are cranking the engine with the starter. But once again, not too long...
Wayne Strausbaugh V-42 C/C RESTLESS September 2000
___________________________________________________________________________________
The Perkins engine
Performance Chart and Specifications Sheet follow:
Perkins 4-108
I placed an electric fuel pump prior to my double set of RACOR filters. It seems to work fine. I was having the problem of getting some air into the filters and could not locate the source after extensive troubleshooting. I did find out that you can run the engine just fine with the RACOR 500 filter having 1-inch of air in the top but I don't want to do that again...
I installed extensive valves around the fuel pump so I can:
1) Run
the engine with an electric fuel pump
2) Run
the engine without an electric fuel pump
3)
Transfer fuel through either filter to any of my 3 tanks (fuel polishing)
4) Use
the fuel pump to top off the RACOR's during filter changes
5) Use
the fuel pump to top off the RACOR's if any air enters the system
The system is pretty complicated and even I have to reference notes every time I switch valving to ensure I set all the valves correctly. The pump precludes the normal use of the RACOR-mounted vacuum gauges to monitor filter condition unless I secure the pump for a reading.
Wayne Strausbaugh V-42 C/C RESTLESS July 2000
Update 2005: A hole in the diaphragm
of the engine-driven, fuel lift pump resulted in some minor dilution of the
engine oil with diesel. The hole was
very small. A mechanic cautioned me
about running an electric fuel pump with an engine designed for manual fuel
feed. I have not used the electric fuel
pump again except for fuel polishing and filling the RACOR filters.
___________________________________________________________________________________
I found a couple of sources for heat
exchangers. One name I got from Harvey, Harpur Marine in
Ray Slaninka
July 2000
___________________________________________________________________________________
Subject: RPM accuracy
There may be yet another thing worth checking if it is fine at "lower RPM" but not at higher. Are you sure about the accuracy of your Tachometer? If you changed the alternator, it may not have the same pulley diameter as the original alternator. The Tachometer on the Perkins Diesel operates off the alternator. After replacing our alternator, but also doing a number of other repairs (replacing engine mounts, flexible coupling, alignment, etc.) I noticed that the engine seemed much more efficient. I now would find that our speed was much higher at a lower RPM. Or so I thought!
I borrowed a flash gun tachometer. It measures the true RPM of the engine by placing a small piece of reflective tape on the main pulley of the drive shaft, and a flash gun, linked to a VOM used to measure true RPM. I discovered that our engine was actually running a full 20% higher RPM’s than indicated on our tachometer. Thus, rather than the reading of 2,000, it was actually going at 2,400 RPM. 3,000 was actually 3,600 RPM. This may contribute to overheating. What prop are you running?
regards,
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You certainly touched on a good point
when you mentioned tach accuracy.
Anytime an alternator is replaced, there is a good possibility that the
new pulley is a slightly different diameter. This really plays havoc with
accurate RPM readings on a Perkins. I used a mechanical tach right off the
crankshaft pulley to calibrate mine. I also had to replace the original
Perkins-supplied tachometer since it had no provision for calibration.
The cruising RPM for your Perkins is
strictly dependent on your transmission ratio. In general, 2:1 ratio's seem to
run best between 1800 to 2200 RPM with a properly sized prop. That RPM range
will increase with a 3:1 ratio. Also, the prop size and pitch will usually be
quite different with a 3:1 ratio. One of
the more common discussions I've heard while cruising, is the happy-hour,
marina comparison of prop size/ pitch/ engine-to-cruising speed and RPM. I remember hearing that "the engine must
be able to reach 3000 RPM underway" and/or "the engine must be
able to reach max RPM underway or the prop is pitched wrong". I have
repitched the prop 3 or 4 times and changed props 3 times trying to make that
happen. I have had my boat
"overpropped" and "under-propped". I finally figured out from a mechanic that
Tayana got it pretty close from the factory and that my Perkins is specifically
designed and rated for the 2:1 transmission that it came with. I use 1800 to 2200 RPM as a good trade off
for speed versus reasonable fuel efficiency.
The performance chart that I posted
is only accurate for a Perkins 4-108 with a Hurth transmission running slightly
less than the 2:1 ratio. That is why you can see the engine developing max
torque in the 2000 to 2400 RPM range. That also explains the 3000-RPM max
cruise RPM. A Perkins with a 3:1 transmission ratio may have an entirely
different torque curve and RPM restrictions.
Wayne V-42 C/C RESTLESS April 2001
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Hi Folks,
I had the same problem with a V-42 and a 4-108. I did everything I could with the water system, heat exchanger, prop pitch (16 inches fixed, changed it from 11 to 10 and then to 12 to see what difference it would make), etc and got the same result - couldn't go over 2200 rpm without overheating and at that RPM could barely get 6 knots and much less than that with any kind of head wind. I talked to one guy who bought a second heat exchanger and installed it in parallel with the first and that solved his problem. But I came to the same conclusion as Bill - a fifty horse motor is not enough especially one that develops its fifty horses at almost 4000 RPM. Its too noisy and vibratey at anything near that speed and it seems as if it would wear out quicker because it has to run at such high revs. At the 22-2400 RPM range we have been talking about that engine only is putting out about 30 horses. So I changed out the engine (in process) to a Perkins-Sabre M65 (same footprint) which develops 65 horses at 2400 RPM. This will allow me to run a serious alternator (250 amp) at very low RPM as well as develop enough horses at lower RPM to push the boat along at something approaching hull speed using a bigger prop. I'll let you know the results.
John B. Van Zwieten July 2002
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Hey
Comrades...
Prudence, my T37, hull #15, with a Perkins
4-108 pushes her along at about 7 knots with about 1800 RPM. As a matter of fact, the previous owners
refused to bring her up to anything beyond 2000 RPM. Seems like a moot point since she travels at
hull speed at 1800. Any ideas? BTW, I don't have any problems with
overheating or oil pressure, etc. All
needle readings nominal.
My question is: What is your normal experience with MAX RPM’s on a 4-108?
John Kalpus Prudence T37 San
Diego July 2002
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On our Tayana-42 we have a newly rebuilt Perkins 4-108 and a new prop. Currently we are able to do about 6.6 knots at 2500 to 2600 RPM's. Any higher RPM's and we overheat. Running at 2300 RPM's the engine runs quite cool and we do about 5.5 to 6 knots.
Now the question: What cruising speed are others getting out of their Tayana-42 and at what RPM? The rebuild shop said we should be able to run the engine up to 3000 RPM or so without overheating and that a change in pitch on the prop would accomplish that. Others have said that we should be able to cruise at 7+ knots. I would appreciate it if anyone with a similar boat and engine would contact me with their experiences and prop size, etc.
Mark Handley S/V Windbird September 2002
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Hi Mark:
Welcome to the conundrum of Perkins 4-108 power in a Vancouver 42. I see Wayne already referred you to the ftp site, but I have to say I haven't been able to get close to the results shown there. We have exactly the same problem as you. I can run at about 2500 RPM’s OK, but also overheat at anything higher. I've pulled and checked the heat exchanger, both water pumps, replaced the raw water impeller, and I and my mechanic can't figure out anything else we can do. One of the posters on this site seemed to have solved the problem by installing a 2nd heat exchanger in series, but I haven't decided to go that far yet. I have a 17" 3-blade max and have tried 3 different pitches, the last finally getting me to close to 6 knots in flat water at 2500 RPM (so I actually envy your 6.6).
Bottom line in my opinion is that the 4-108 at 50 hp seems to be about 25 hp underpowered for this 30,000 lb. boat. I talked to a Van 42/Perkins owner in the Caribbean a couple of years ago who summed the situation up pretty well - sails great but powers like stink. We still have about 4 years before we break out for our 2+ year cruise, but I expect as that time approaches we might just bite the bullet and repower with a 75-horse Yanmar.
Bill Rohde Jubilee V-42 PH Cutter September 2002
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Hi Mark and Bill,
I solved my overheating problem by adding a second heat exchanger on my Vancouver 42 CC. I can now motor at 2650-2700RPM all day and do 6.5 to 7.2 kts depending on the wind and seas. I did not change the prop at all. I can send you details if you want.
I have a Borg Warner Velvet Series 1000 transmission with a ratio of 2.13:1. The stern really squats down above 2500RPM too. I think that all displacement hulls do that.
There are specs on the FTP site for the Perkins 4-108 (chart is reprinted above). The engine's net output is 39hp @2700 and 47hp @ 4000RPM. Seems like a lot more noise for not much gain.
I agree with John Van Zwieten that the 4-108 is not enough for the V-42. In fact, I visited our local Tayana broker and he told me that Tayana is putting a Yanmar 75hp engine in a new one that they just sold.
What sort of fuel consumption do you have when you run up to 2500RPM?
Doug Simms September 2002
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My tach (as I believe most diesels do) comes off the tach. Also, I can only get 2200 RPM indicated on mine at full throttle, so am not sure I trust it until I can find an optical tach to borrow sometime so I can verify it.
By the way, for anyone concerned with
the overheating issue, I solved mine. The symptom was that it would run fine
for 10-60 minutes, then overheat (faster at higher throttle than at lower). I
pulled my heat exchanger, filled it up with Lime Away (purchased at the local
Longs drug store) and left it over night. By morning, the foaming had stopped
and there was 1/4" - 3/8" of what I think was calcium carbonate
sludge in the bottom of the bucket. But it back together and now I can't get it
to overheat even at full throttle.
For the record, removing and
replacing it was not as difficult a job as I had feared.
Fair winds - Dan Best September 2002
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The Perkins 4-108 is not powerful enough to run the V-42 at hull speed unless it can turn at over 3000 RPM. Its 50 horses are only developed when the engine turns 4000 rpm. I can't tell you how many people I have talked to with the same overheating problem. There are only two solutions I have heard that work.
1. Add an additional heat exchanger, which doubles the cooling and makes the engine almost impossible to overheat. I have talked to two other V-42 owners, a couple of owners of other large cruisers with 4-108 and a couple of mechanics who have done this with good results. I have come to the belief that the 4-108 just does not have enough cooling capacity to run at high enough speeds to develop its potential horsepower.
2. Get another engine that is more powerful at lower RPM’s. This second choice is the path I have taken by installing a Perkins/Sabre M65: 65 horses at 2600 RPM. I get 7.5 knots cruising while turning 2400 RPM. And I have the spare HP to turn a second 240-amp alternator.
Changing the pitch of the prop is something you can play with. I tried it with the 4-108 and it didn't work but you may have better luck. I tried increasing the pitch from 11 to 12 - nothing. Theoretically, if you lessen the pitch you can run the engine faster under less load thus increasing the available horsepower of the 4-108. I went the other way increasing the pitch to provide more propulsion at the same RPM that had no effect I could see. I haven't heard of anyone trying to lessen the pitch and running the engine faster so I don't know if that works. I believe that the V-42 hull speed is 7.6 knots which should be the goal, in my mind, of your efforts vis-a-vis cruising speed.
John B. Van Zwieten September 2002
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I've got a CT37 with a Perkins 4-108. There seems to be a LOT of differing ideas over the max RPM of the ole Perkins. I get 7 knots, hull speed, with my Perkins only turning 1800-2000 rpm. I think I've got a 16x9 RH prop and she does just fine with that -- no problems. My Perkins shop says that 1800-2000 should be fine -- as long as I can reach hull speed and not under or overheat. Just my two cents -- I'd love to hear other opinions. Happy sailing.
John Kalpus Prudence CT37
San Diego September 2002
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Thanks for the info. I had a 2-blade 16 x 11 and changed to a 3-blade 16 x 10 with good results - went from about 1800 RPM max to 25-2600 max before overheating. Speed increase from around 6 to over 6.5. I am tempted to try going one more step down on the pitch to see what happens. Or adding a second heat exchanger, if I can figure out how that is done...
Mark V-42 September 2002
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If you decide to do the rebuild, I'd
suggest you also consider using TransAtlantic Diesels down in Virginia. The guy
that runs the operation is a Brit who specializes in rebuilding Perkins. His
reputation is very good, has been in the business a long time, and the price you
were quoted from Mack Boring was close to what he charges, as I recall. Check
out his web site: www.tadiesels.com.
Regarding 4-108 removal, it was no
problem once we removed the transmission. We put a 4 x 4 across the
companionway, lifted the engine slightly with 2 come-alongs, then slid the 4 x
4 forward until the engine cleared the bulkhead. We had the yard's crane lift
it out from there. The only trick is to rig your lifting chains so that the
back end of the engine can be tilted downward and the engine can be spun around
180 degrees as it goes through the companionway opening. (Be sure to drain your
oil first!!!).
In round figures, the new engine costs were roughly as follows:
Engine (excluding tax) ..………………………………………..$9500
Transport fee...............…………………………………………...200
New engine supports..(2 lengths of 4" Angle iron w/ welded
hypotenuses).............…………………….…………………...180
New prop................………………………………………...…...300
New prop shaft.......….…………………………………………..200
Exhaust flange......…………………………………….…….........100
Flexible prop shaft coupling………………………………….…...150
Miscellaneous hoses, hardware, wiring, clamps, control
cables.....................………………………………………….500
The biggest headache we had during
the installation was that the factory shipped us a larger transmission than the
one we ordered (KM4 instead of the KM3), so the engine mounts were nearly 2
inches wider than the spec sheets showed. (The larger transmission was provided
because they apparently have been having some problems with the torque
converters on the KM3 in heavy displacement boats like ours; the KM4 is beefier
and does not need a torque converter). As a result, we had to grind over an
inch out of each of the engine stringers; a VERY messy and time consuming task.
And to add insult to injury, the dealer set up the engine installation jig
incorrectly, so when the engine arrived, it sat over 2 inches higher in the
hull than it was supposed to. Those 2 mistakes cost us about 30 hours to fix.
All told, we spent somewhere around 125 hours on labor for the whole job,
although someone more experienced in engine work could probably have done it in
half that time.
So, would I go this route again if I
had it to do over again? Probably so. Despite the added cost and headaches with
figuring out how to fit in the new engine, I had heard too many stories of
rebuilds gone bad to want to go that route. I also was concerned about the
future replacement parts availability for the 4-108 given that it has now been
out of production for 20 years. I also was concerned about the unavailability
of a detailed shop manual for the Perkins. (Someone with more experience might
be able to get by with that 120-odd page manual that Perkins published, but I
felt I needed more information than it contained). And finally, those
inevitable oil leaks!!! It took me many, many hours of scrubbing and painting
to rid the boat of that old oil smell, and I didn't want to ever go through
that drill again. (Question: Why don't the English build computers? Answer:
Because they can't figure out how to get them to leak oil.)
If you do decide to go the new route,
however, I would seriously consider some of the other options out there. In
particular, I'd look closely at the new Volvo engine. It is a slow turning
engine, like the Perkins, which should be very durable, and I believe it is
narrow enough to drop into the existing stringers with very little
modification. Even though the new Yanmar is relatively quiet and smooth, I need
to crank it up to 2600 RPM’s to get to cruising speed vs. the old Perkins 1800
RPM’s. At that speed, I doubt the Yanmar will give me 7,000 hours between
rebuilds as did the Perkins. (Cruising World or Sail Magazine just did a review
of all new marine engines in the 50 HP range - I can make you a copy if you
don't have it). Good luck. Keep us
posted on your decision.
Dayton Eckerson T-37 #215 MISTRESS November 2002
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My 3qm30 is running at over 7900 hours. From what I read, it is not uncommon for this engine to run to 12,000 hours if properly maintained before a rebuild is needed.
fyi, John, s/v Celtic Dream June 2003
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I've got a 76 HP engine in a V-42 (weight 31,000 lbs.) and it's over powered. When past 80%, I get gushers of water coming in the cockpit from the scuppers & the stern squats comically. Unless something very strange happens with T-37's, that engine is more than adequate.
Paul V-42 August
2003
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Paul:
I'm about ready to swap out my Van
42's Perkins 4-108 for a turbocharged Yanmar 4JH3-TE. I find the Perkins just
too light for the 30K+ lbs. of boat I have, plus its horsepower curve requires
you to run the RPM’s way up just to get near-50 horses out of it. I've played
with our Max Prop to try to achieve a reasonable balance, but find the Perkins
just doesn't have enough guts for the 42. It would probably work good on a 37,
but the 42 is just a bit beyond Perkins sweet spot.
Lots of other Van 42 Perkins owners
on the list have told me the same thing (poor power performance with the
Perkins), except for one who claims to be able to drive his Van 42 with a 4-108
at 7+ knots easily. Can't figure out how he's doing that. I can maybe reach 6 in flat water, but in the
5's with any slop. I suspect I could
better that a little bit with one more pitch adjustment, but after tweaking the
pitch again I know I'd need to be running the engine close to 3000 to get over
6 knots with the engine (& that assumes that the engine would have enough
punch to get up to 3000 RPM in the first place).
So ... bottom line, what engine do
you have. Seems to be better to have a bit more power than you need than too
little. Overall are you satisfied with the engine? I assume you can run her up
easily to 7 knots without experiencing the "geysers" in the cockpit
scuppers. I'd be more than happy with
that, plus it sounds like you would have some reserve for when you need to
drive upwind in any kind of sea, or power out of a dicey situation, which I can
barely do now.
Bill Rohde V-42 August
2003
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Bill,
The designation on my engine is (Yanmar) 4JH2-TE. The rating is 57kw maximum which I figure to be about 76 hp or so. There is no issue running the boat at 7 Kts water speed which is only a bit over 2k rpm. That's just below or right at where the turbo kicks in.
There is a LOT of reserve for running against wind/tide. I do not have the prop spec's here nor will I be at the boat any time soon where I have them. I have a fixed prop.
My slight concern is that I run the engine too lightly. Diesels run better when run closer to their rated output than where I do. I like this rpm because it gives a very relaxed and quiet ride. I, from time to time. rev her up just to decarbonize the engine. I have no idea how often this should be done or if my doing so really does help matters at all. I tend to run with some light gray smoke or no smoke at all, but I do get some black deposit on the side of the boat where the exhaust exits. This washes off easily.
I'm perfectly happy with my engine so far. I think technically I may have done better with less of an engine, but it was Chris' idea (previous owner) to install this one. I do like it being quiet and smooth in ops. I'm near 800 hrs with no unscheduled maintenance at all.
At my low cruise, which in still water is about 7kts, consumption is 1 GPH or maybe 1.1 GPH. I can't seem to get a clear reading due to uncertainty about when my tanks are full.
Paul Cassel V-42 August
2003
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Thanks for the info, Paul.
I'm looking at a 4JH3-TE, which I think is simply a later generation of your engine. Specs say 69 horse sustained at 3700 rpm, 75 horses peak at 3800 rpm. At about 2K rpm, the engine power curve looks like about 47 HP. At 2000 RPM, my present Perkins 4-108 is rated at less than 30 HP.
If you get a chance some time, I'd be
interested in the diameter and pitch of your prop. Also, the reduction ratio you have in your
transmission (I assume you have a matching Yanmar transmission)?
Thanks again for the prompt reply.
This is looking more and more like the way I want to go.
I was told by the previous owner that
the engine was rated at 66 hp. Then I
read the tag on the engine and got the 57kw which is why I said about 76 hp. When I'm again on the boat, which may be
quite a while, I'll remember to spec the prop.
I don't think that spec'ing the props for these boats is tough for pros.
Bill Rohde V-42 August
2003
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It always seems that leaks occur in the
strangest places... How about this one! I came back aboard after a week away
and smelled diesel. There was almost a half-gallon underneath my Perkins 4-108
but luckily it was in a plastic container set on the drip pan. The container
was there to catch oil dripping from the engine due to a partially blown, rear
oil seal. The last time I replaced the seal, I figured the engine would leak
again sooner or later so I drilled a hole in the bell housing so it would
only leak (drip) in one place. The
diesel only dripped out of the engine due to the bad rear oil seal. I don’t know where it would have gone with a
proper seal…
So I checked the oil level in the engine. All the way up the dipstick! I started pumping out the oil. My 4-quart sump yielded 2 12/ gallons of oil and diesel. The engine was virtually flooded! I thought it might be the diaphragm on the fuel lift pump. That had failed before and diluted the engine oil with a little diesel. I caught that with oil analysis within 20 engine hours and sustained no damage. I replaced the lift pump (a cheap and easy job) and motored 2200 miles without problem. So I called a mechanic and he said that a Perkins can only leak into the sump from 3 sources: the fuel lift pump, injectors (but not gallons - just small amounts), or the fuel injection pump. It was the fuel injection pump due to a seal failure around its internal drive shaft. Just a mere $625 later, I am ready to reinstall that pump. And that's for an overhaul. New is twice that!
My lessons learned:
1) Check oil level before starting the engine. Excessive levels means diesel or water... If you try to start an engine flooded with fluids, it may bend something due to hydraulic lock.
2) Best not to leave the engine with a fuel tank selected that can gravity feed the engine. Use the bilge tank when laying up. Or secure the fuel at the manifold.
3) A large plastic container in the oil drip pan gives double protection...
4) If you have more than 4000 or 5000 hours on a Perkins 4-108, change out the fuel lift pump as a precaution.
Wayne V-42 C/C RESTLESS November 2003
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Subject: Opinions on horsepower for V-42 and T-37
I'm seeking opinions on the adequacy of the
horsepower for engines for Tayana 37’s and 42’s. How much is really
enough? In rendering your opinion,
please assume the boat will be used for cruising anywhere in the world. Thanks!
Lauren O'Connor January 2004
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Lauren:
After four seasons of fiddling with
Max-Prop pitch settings with our Perkins 4-108-powered Van 42 Pilot House
(which I believe displaces out at 2-3 thousand pounds more than a standard
Center Cockpit or Aft Cockpit Van 42), we've decided to bite the bullet and
re-power. We're presently re-powering with a new Yanmar 4JH3-TE which peaks at
75HP, about 50% more peak HP than the Perkins and considerably more HP lower at
lower RPM ranges.
Will this be more than I need? Possibly. I've heard of others with the
naturally aspirated predecessor to this Yanmar (I think about 65 HP) who have
been quite happy with it. That said, in my opinion the Perkins, while a good,
dependable engine, is marginal at best for a boat the size of the Van 42. Could
one live with the Perkins in that boat? Certainly. I did for 4 seasons, but I
wanted more engine for when we eventually take off on our cruising sabbatical
in a few years.
I can't speak for the T37, but that
boat is likely enough lighter than our Van 42 Pilot House for the Perkins 4-108
to be an excellent match.
Bill Rohde January
2004
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I think that I am under-propped. I can run at 3000 and above (according to the tach) easily. I usually cruise at 2800, which corresponds to about 6 knots (per the GPS). I intend to measure my prop next haul out.
Speaking about temperature, my Perkins usually runs just under 180 F. On a recent trip to Ensenada, the temp gradually rose to above 200 F. Not too long after this the engine quit due to a clogged fuel filter. After I changed the filter and got the engine going again, the temp ran consistently at the old 180 F value. I am thinking that a fuel-starved diesel must run hotter than usual.
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Yup, if you inject the 'precisely correct fuel mixture' into any piston engine, the combustion chamber will essentially 'be too hot' and can be quickly damaged. All piston engines are 'over-fueled' to prevent thermal damage .... the excess/unburned fuel helps to cool the combustion chamber. If you were 'starving' with a lean mixture, not enough excess fuel will be available to evaporate to help sweep the hot gases out of the chamber.
Rich Hampel October 2004
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Subject: Perkins 4-108 fresh water coolant pump
That pump does not have the rubber impeller blades and therefore is not as susceptible to damage and doesn't need replacement as frequently - but others who know more than I about Perkins may have different opinions and would easily be better qualified than I on whether or not to carry a replacement.
Here is something you should be warned about. I was cleaning my engine by spraying lots of engine degreaser on it. The degreaser apparently got into the sealed bearing of that water pump (that's my guess to explain the trail of black, gummy material down the engine from a small hole in the bottom of the pump).
You can't change or regrease that bearing. And there is a somewhat delicate ceramic part in there with the bearing. Tried to remove the pulley to put it onto a spare pump that I have (from a previous owner) and the pulley broke. It is made of a brittle metal. It cost almost $200 to replace the pulley, the gasket, and to have it pressed on my spare pump. They use a special tool to pull the pulley. And a special press to put it on.
Keep that problem with the changing the pulley in mind when swapping out a pump. If I were to get a spare, I'd make sure it had a pulley already on it. I'd take it and install it and put the original away as the spare - with gaskets.
The pump shaft's changed over the
years in a way that is confusing. The
early ones had a clip-ring at the end. Press the pulley on just far enough to
be able to get the clip ring onto the groove in the shaft. The newer pumps have shafts that a just a
little shorter and have no groove. That is okay - the clip-ring is not
needed. It is critical that the pulley
be at the right distance onto the shaft to ensure it is in line with the other
pulleys or the belt will wear away.
Also, you have a plate that lives under the pump - between it and the engine block. That means that there are two gaskets. You will need to do lots of scraping to get the metal very smooth and clean when putting all of this back together.
Now you know more than I do about 4-108 Perkins fresh-water/coolant pumps.
Steve Wolfer s/v Island Girl December 2004
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Subject: Marvel Mystery Oil
I keep a storage of 'change-out' oil composed of 25% Marvel Mystery Oil : 75% regular Rotella.
Drain (suck out through the dipstick) the old oil - discard.
Refill with 'change-out' oil, run at no load until warm.
Let sit for 1 day (or more)
Drain (suck out) change-out oil and return to storage. Change filter.
Refill with Rotella. etc.
The MMO will help remove the carbon
deposits in the piston ring grooves (etc.) .... probably the largest vector of
cylinder wall wear in a diesel (blow-by and compression loss). For winter
storage I fill the crankcase with 100% MMO run at NO load until warm and then
shut down to let it soak for 3 months. With 100% MMO never run the engine with
any load, just high idle. Works on automotive gasoline engines also to prolong
engine life. I you cant find MMO then 25% Automatic transmission fluid is a
good substitute.
Rich Hampel January 2005
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Finding system cooling / heat transfer problems is quite easy.
The most common causes are:
1. broken rubber vane on a waterpump impeller .... change yearly.
1a. broken vane has migrated down stream and is now partly blocking a tube/passage
2. Blocked inlet strainer.
3. Partly closed exhaust exit/discharge throughhull valve (almost ALWAYS forgotten to be reopened).
4. If raw water cooled, fouled engine
5. If freshwater cooled, fouled heat exchanger
6. Fouled exhaust manifold - huge rust platelets breaking loose from the casting internals and
blocking the flow channels
7. Blocked wet muffler system water injection nozzle.
8. Lean-burn (fuel-air mixture ratio) engine (rare)
9. Under pitched prop ... engine doesn’t develop full rpm/max. HP under full load.
10. Over tightened propeller shaft stuffing box.
11. Stuck/sticking thermostat.
FIRST, verify that the water flow rate at the hull exit is within spec. -
found in your engine manual. Take a
bucket and stopwatch, run the engine at the specified rpm and verify. Should be
about 3+ gallons per minute at 2000 rpm
... check your manual.
SECOND, establish maximum rpm at hull speed.
THIRD, is temp sensor intact/working?
Disconnect elec. leads to note gauge change then reattach - if the needle
'moves' then its probably OK.
THEN ........
If there is sufficient (to spec.) flow - as verified in 'FIRST' above, then the system is probably fouled (or the fresh water circuit of the heat exchanger/engine is blocked/fouled). If fouled, then use a commercial boiler de-scaler such as Marsolv (www.marsolv.com) or Rydlyme. these are organic acids that will NOT dissolve the base metal of the engine as will acids (hydrochloric or muratic, etc.). Simply drain the water, add the de-scaler and let sit a few hours/days, then flush.
If there is not sufficient flow, then examine the system, retrograde - from the
exit back to and through the intake.
Caution: save the injection nozzle on the water lift nozzle inspection for last as the carbon steel 'riser' piping is usually weakened or corroded due to the hot corrosive exhaust gases .... sometimes you can 'get away' with a disassembly without harm .... but not very often.
Check the water pump vanes (the fresh water pump usually has rigid metal impeller vanes and doesn’t need replacement unless there is water gushing out from the shafting seal). Replace the rubber raw water impeller and grease the shafting (zerk fitting or screw cap) ****yearly****.
Remove the rubber hose that connects between the exhaust manifold and the water
injection nozzle of the water lift muffler. Briefly run the (cold) engine to
2000 rpm or the spec. rpm discharge the hose into a bucket, measure the time
fill and compare the flow to the exit flow rate.
If MORE than the output (low) flow rate, you probably have a blocked injection nozzle to the water lift. The dissolved carbonate salts that are dissolved in seawater become precipitating solids when sea water reaches above 150 degrees F.
These 'salts' (rocks actually) once formed are insoluble and accumulate and block BOTH the exhaust gases and injection water. Same thing happens upstream inside the engine where the metal surfaces in the cooling passages approach over 150°. Think of constipation!!!! Visually you will see a 'rock' growing just downstream of the injection port/nozzle. Injection elbows/nozzles are cheap ... and so is all the carbon steel pipe and pipe cladding needed to rebuild the heat riser / loop.
If NO change when you check the discharge from the exhaust manifold, reattach
outlet hose and disconnect the small hose (elbow) between the engine and the
inlet to the exhaust manifold, measure the flow and compare to the output
value.
If MORE than the outlet value the exhaust manifold is blocked with rust/scale. These iron casting degrade by issuing HUGE platelets of rust from the side walls of the internal casting (lap defect of casting process - quite common). A stiff wire pushed against the lodged flakes usually will break them or break them loose ... if not then new manifold. Note: if the water was drained from the engine and the engine was stored 'dry', the rust flakes will PROBABLY be the cause of the blockage - don’t ever let the cooling system internals dry-out as drying out vigorously promotes severe rust and rust flakes. Always store the engine 'wet' and with corrosion/rust inhibitors in a totally filled cooling system. Note: if you remove the manifold, be sure to pressurize the manifold with full-pressure 'hose water' (30-60 psi). Then look for pinhole leaks of water flowing from the ‘water’ side into the 'gas' side. A pressure check of the exhaust manifold will prevent engine destruction when the engine shuts down and water from the pin hole leaks fills the cylinder/combustion chamber - pistons rings 'freeze' in their grooves and the valves become frozen and stuck.
If inlet flow EQUALS the exit flow at this point .... then definitely a fouling problem or blocked inlet strainer, etc. ..... OR (hold onto your wallet) engine combustion problems.
There is a possibility that the engine is has a huge bubble or air entrapped inside the engine block (air bound). Air will not allow the temp gage sensor to work --- the gage will show low readings when the engine is actually hot.
Remedy, close the inlet valve or pinch the hose with a vice grip, remove the "highest hose' on th engine (that little elbow between the engine and the exhaust manifold) and manually fill the engine through the piping to remove the trapped air, reassemble and check operation.
Normal engine fuel supply is typically 5-10% too rich with the excess
over-fueling used to cool the combustion chamber with unburned fuel. If the
mixture is too lean the combustion chamber becomes too hot (and engine
overheats as it destroys itself). Remedy: rebuild high pressure injection pump
... can you spell $$$$$$$$$$$$$$ or clean/replace the inlet fuel filters .. not
so $$$$$$$$$$
From the SECOND step above..... if the maximum rpm at hull speed is greatly
below the specified MAX. rpm at max. developed horsepower (look at the 'power
curve' in your manual (developed HP vs. rpm) ... the prop is probably under
pitched and the engine is 'lugging': too low a rpm (hp) for the applied load
... the engine is grossly over fueling and the 'fire' is propagating past the
exhaust valves .... and the combustion pressure is sky-high and the wrist pins
and main bearings are taking a 'shellacking' ... and the engine will
prematurely wear-out. OR the engine governor needs adjustment (call in the
diesel mechanic time).
For foolproof operation: At least yearly --- change the rubber pump impeller,
grease both pump shafts, clean the inlet strainer, measure and record the
volumetric water output flow rate at the exit, change the engine and heat
exchanger zincs. Every two years: de-scale the raw water side of the engine
(every year if raw water cooled (no heat exchanger)), Commit to memory the 'thermal characteristics' of your engine
running at 'cruise' rpm by 'touching' all major components of the cooling
system with your fingers.... how FAST you pull your fingers away will give you
an impression of the various surface temperature (obviously don’t touch the
bare 'heat riser' - that vertical set of pipes between the exhaust manifold and
the entrance to the water lift muffler.
BTW the heat exchanger is normally designed for a 15 degree 'approach' so that
if the inlet raw water exceeds 90 degrees, the thermal efficiency of the
exchanger is be quite 'marginal'.... You don’t state where the boat is .... and
if you’re anywhere near 90+ degree water and I’m still ice skating/skiing ............... I’d be damn jealous of your
overheating problems.
Other, ...... don’t bother to buy a new super-expensive marine engine
thermostat. De-scaler compound will
usually clean it up and restore it back to operating correctness.
Hope this offered analysis protocol
helps. There's more to this but the above will cover about 95% of all cooling
'problems'. Yearly maintenance and burned/blistered fingertips will prevent a
lot of future agony.
Rich Hampel T-37 February 2005
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Subject: Volvo Penta diesel
Hi everyone. Has someone heard anything about the new Volvo Penta 100 Horse?
I have heard some negative things about the old Volvo's but the new (2 years old) version seems pretty good. I am considering a Yanmar or the Volvo Penta. I think 100 horses is also a little much for a V-42. The previous Perkins ran for 24 years but there are no Perkins Marine dealers in the Toronto area. Any experience out there with the new Volvo?
David Campbell Coco I Toronto February 2005
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I have never met a satisfied Volvo
diesel owner but plenty of dissatisfied ones. The cost of parts was a common complaint
I heard from many.
I had a Yanmar on my last boat and
don’t know how many thousands of trouble-free hours I put on it. The new Tayana has a Yanmar and I’m very
pleased with its performance so far.
John Lewis February 2005
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John, Harvey,
I wholeheartedly agree with you regarding the Yanmar. However, my VP MD17C still runs good with only ~1500 hours on it and I'm just going to have it checked out. With two girls in college I've got to make this baby last for a while!
John Keefe CT37 No.63 ODYSSEA Youngstown, NY February 2005
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Hey John,
The comments were based on my impression that your engine had died, and they you were looking into replacing it with a Volvo 100 hp. If your engine runs well, pay tithe to the mechanic and keep it running. I bow deeply to our old Perkins 4-108 every time I get on the boat. I'm not sure what I would do if that died. I found a good mechanic in San Diego, and have him go over it about once a year. It's close to that time. Last year he changed the front oil seal and the exhaust elbow. Not a lot of work, but it still cost a bit more than a BOAT UNIT. But a new engine would be prohibitive.
regards,
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Subject: Perkins thermostat
Harvey is right about the opening temp of 156 degrees. I tend to call it a 185-degree thermostat but I don't have a clue what a mechanic would refer to it as. Here are the specs from the 1978 Perkins Workshop Manual:
Thermostat (Indirect Cooled Engines - anti-freeze in block)
Type: Wax capsule
Opening Temperature: 156 degrees F
Fully open at: 188 degrees F
Minimum Travel at Fully Open Temp: 0.281 inches
Thermostat (Direct Cooled Engines): (salt water in the block)
Type: Bellows
Opening Temperature: 125 degrees F
Fully open at: 150 degrees F
Minimum Travel at Fully Open Temp: 0.281 inches
Wayne Strausbaugh May 2005
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Subject: Perkins 4-107 Thermostat replacement
Hi Wayne,
Many thanks for the clarification. I had initially pulled out the original thermostat, and was told to replace it with a standard 180-degree thermostat. The engine overheated. I then took my original brass Perkins thermostat, boiled it in vinegar for about 30 minutes to remove the caked salts, and then could clearly read that it said something around 156 degrees. But that is the initiation of opening, as you pointed out. I found that it finally opened fully at about 180 degs. F. I then realized that the original thermostat was still in good condition. I removed the new thermostat, and put the original back in. After then bleeding all the air from the system, my engine sat comfortably at about 175 degrees at all RPM’s. The only subsequent change in temperature happened when I added a circulating hot water heater from Accuheat (same as the Red Dot heater), and the temp then dropped to 165 degrees. F. Although that is a bit low, and with heavy motoring I can send it up to about 175, I decided to stay with the thermostat.
regards,
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Hi Harvey,
Do you think the old thermostat kept the engine cooler or do you think you had not completed all the bleeding when you were running the new thermostat? I think the cooling systems on all models of the 4-108 are just a little on the small side. As you indicated, adding even an auxiliary heater increases the cooling capacity. Remember Doug on Aquadesiac? He installed two heat exchangers in series to handle an overheating problem. He reported that it worked quite well.
Wayne V-42 C/C RESTLESS May 2005
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Subject: Using engine freshwater seacock as an emergency bilge pump
FYI, the Perkins 4-108 pumps 5 gallons/minute through the cooling system at idle. Probably triple or better at higher RPM's.
Wayne V-42 C/C RESTLESS May 2005
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Hi Wayne,
When it comes to cooling systems, it almost makes be believe in trolls, goblins, demons and hobbits. When we first bought Night Heron, it started to overheat during our first long trip, and we struggled with it for many months. The temperature would quickly rise to 200 degrees F., and with any substantial load it would hit 212 degrees F. and higher. We replaced the fresh water pump, the salt-water pump, thermostats, cleaned the heat exchanger, and even the exhaust lines. We replaced the electronic thermometer with a simple direct reading thermometer in the engine block. The simple fix that seemed to finally make all this effort work was putting on a petcock on the heat exchanger. The petcock was on a 2' long piece of heater hose. This allowed me to properly bleed the cooling system. My conclusion was that each of the things we replaced were in need of replacing or repair, but without properly and completely bleeding all air out of the system, I was getting airlock and the cooling system wasn't properly circulating the cooling fluid. (The mechanic who did all this work was not the one who finally asked me if I was properly bleeding the system. It was a local Perkins mechanic, who mentioned this almost as an aside "I assume you thoroughly bled the system, didn't you?" Huh? "Well, why don't you just put on a $2 petcock?") I subsequently also replaced the heat exchanger completely, as well as the waterlift and the exhaust elbow. By that time, I finally managed to get the system to sit down at about 175 degs. F. I then installed our hot water heater, and that didn't seem to have much effect on the system temperature. But when I added the Accuheat heater that resulted in a drop in temperature of about 8-10 degrees. F. This is surely due, in part, to the fact that the heater is several feet away from the engine, and there is probably heat loss in the hoses from engine to the heater and then back to the engine. There is also the obvious heat exchange occurring in the Accuheat heater itself.
But the most important thing is to
properly bleed all air out of the system, and to have a suitable way of doing
this at the highest point in the system. The bleed nut on the heat exchanger is
a disaster, and guarantees that you will scald your hand, and then drop the
bleed nut into the deepest part of the bilge!
Tracking down the overheating engine
problem ended up costing me well over $1,000, and I was ready to sink the boat.
Fortunately, since that time, (and at risk of inviting disaster), we have had
relatively few problems with the engine for the past 5 years. I hope it
continues that way. I did have the front engine oil seal and the transmission
rear seal replaced about a year ago, when they were found to be leaking. But by
that time I had become inured to the big bills and high cost of maintaining the
boat. I silently utter a prayer every time I start the engine.
But I suspect that some of the
problems that our group may be having is due to calcific deposits in the heat
exchanger, others due to airlock, some due to bad fresh water pump, poor status
of impeller, plugged cooling system, encrusted exhaust manifold. I think that
an encrusted thermostat does contribute to the problem, but that may be one of
the least likely sources of the problem.
Harvey T-37 May 2005
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I’ve wondered about the zinc, or lack
thereof, on my 4-108 although any research efforts always led me to the same
conclusion -- that there isn’t a zinc to replace and no easy way to add one.
How does one identify a “New” 4-108? Are there “Old” 4-108 with Bowman heat
exchanger? Why the design change from zinc to zinc-less?
Thanks, James May 2005
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James,
Look (above) at the Perkins spec sheet. It shows a Perkins with the Bowman heat exchanger. The tube stack is insulated by the rubber boots so it has no direct electrical connection to the block. Evidently, Perkins thought that no zinc was required. Some people buy the inline zinc holder that goes on an engine cooling hose. I had one but removed it. Don't know if it did any good... I also posted general pictures of Perkins 4-108 engine cooling configurations on the ftp site at www.tayanaowners.org under “Owners Posts”. There was no "old" Bowman setup. It came about around 1980 or 1981.
Wayne Strausbaugh May 2005
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Check out the thermostat in pan of boiling water on a stovetop.
Fill with water, throw in the thermostat, turn on the heat and watch the thermostat and a thermometer until the water starts to boil.
A long, rolling boil with vinegar usually clears most sticking thermostats.
Your temp problem 'may' only be that
the raw inlet water is still so damn cold that the 'bypass' orifice flow in the
thermostat is overwhelming the system. This assumes that your thermostat has an
orifice in it so that there is always some water passing through it.
Rich Hampel May 2005
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Subject: Thermostat replacement
Replacing the thermostat is quite straightforward.
The first thing to do is read the Perkins manual so you will know where the
thermostat is located. (on our 4-108, the coolant tank is across the middle of
the top front end of the engine. The thermostat is located under the port
corner of the coolant tank.) You access the thermostat by draining enough fluid
so that the reservoir coolant tank is about dry. You drain the fluid by removing one of the
coolant hoses that are below the level of the coolant tank.
Lay out your tools and plan of action.
Take digital photos at each step of the way, so that you will be able to re-assemble it later.
Drain the coolant tank.
Disconnect any hoses running to or from the coolant tank. Label them clearly.
Remove the 2 or 3 bolts that hold the tank in place. Be very careful, as they may be frozen in place. If you break one, it is a big PITA, but can be repaired with a stud remover. You will have to go to a local Perkins dealer to find a replacement stud.
Lift off the coolant tank. You will now find the thermostat. (If there is one there. If the engine had chronic overheating problems that were unsolved, the previous owner may have completely removed it.) Do NOT remove it. Stare at it, and take a picture so that you will remind yourself which is the top and which the bottom.
Carefully lift it off and save the paper gasket. You will not use the gasket again, but you will need it to purchase the correct replacement at NAPA. Buy several spares. They are cheap. Examine the thermostat. If it is encrusted, I suggest that you boil it for 30 minutes in a concentrated solution of vinegar. If it was installed using "Liquid Gasket" (the blue goo), make sure that it didn't spread onto the thermostat itself. That alone can cause a thermostat to malfunction).
Once the thermometer is clean, you should be able to read a set of numbers
inscribed on it. The original factory Perkins thermostat says "156
degrees" - that is when the thermostat STARTS to open. It will fully open
at about 180 degrees.
Now test the Opening/Closing temperatures of the thermostat. Put it in a pot of
water, insert a "Candy thermometer", and turn on the heat. As the
temperature rises to 156, the thermostat should start to open. Let it go on all
the way to boiling at 212 degrees. See when it appears to be fully open. Remove
the thermostat from the boiling water with a pair of tongs and set it down to
cool. Did it open smoothly. If not, you will need a replacement. Even if it is
in good shape, it's wise to have a spare thermostat on hand. Under any
circumstance you will need to replace the original paper gasket. You also need a
tube of that Blue Goopy Liquid Gasket material. A small 3 oz tube will cost
about $6. All those things can be purchased at NAPA or any auto supply store
such as Pep Boys or Kragen.
If the thermostat is bad, you need to get a replacement from your local auto
parts supplier. They are cheap, but not as good a quality as the original
Perkins made of nice brass colored metal. They may not have the units with the
correct temperature. Remember that gasoline engines often are designed to
operate at higher temperatures than are diesels. You want one that starts to
open at 156 to 160.
In reassembling the system, just reverse all procedures. But replace the paper
gasket with a new one. Put on only a thin film of the Blue Gasket goo. Excess
amounts will jam the thermostat. The
actual process of disassembly and reassembly will take an hour the first time
you do it, assuming you don't break any bolts. By the third time you do it, it
will take less than 10-15 minutes.
The critical things are:
1) Have a big jug to collect the antifreeze. It is a violation of environmental regulations to pump it overboard due to the toxicity of ethylene glycol. (Forget the fact that anybody with a car dumps it into the street, where it then flows into a storm gutter, and then into the ocean!) If you do collect it carefully, you can reuse it, so work with a clean jug.
2) Line up all your tools. Socket wrench to remove studs holding coolant tank in place.
3) Digital camera to help you figure out why it doesn't go back together as readily as it came apart.
Good luck, Harvey May 2005
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Getting back to basics, for my money, plot out on paper the actual engine cooling flow, ALL hoses. Check that against the engine/boat manual.
As
If it's a new problem 1st look at something that you have changed (e.g. new
water tank, new hose etc.
If you haven't changed anything look for something that has broken/worn out.
Start at the most obvious problem areas, thermostat, impeller.
It's all logical :-)
It took me days to identify that when
I took the plate off the water pump to check the impeller and that putting the
plate back on with a gasket (1/16" thick gasket - it looked like it should
have been on there to begin with since the plate was scored by the impeller)
that this 1/16" would let enough water by-pass the impeller action and
kill the engine cooling efficiency. By this time, I had ripped every wretched
heating hose off (they are still not re-connected but who wants hot showers
anyway), taken out the thermostat (it's still not in but who wants a hot engine
anyway) plus had every marine "engineer" in the yacht club in for a
beer, consolation and advice.
Bill & Sue, T37 Wellantanzerin, TYA3725707 Port Hope, Canada May 2005
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Harvey, I had to grin reading your description of changing out a thermostat.
On Kamaloha, which has a Yanmar 4JH3E, it was more like this when I did it in
Bequia:
(My coolant reservoir is not in the way)
0) Read the Yanmar service manual to figure
out where the thermostat was located.
1) Removed two bolts holding thermostat bell in place. Noted they weren't the same.
2) Loosened the hose clamps holding hose to bell.
3) Pried bell off. A few ounces of coolant ran down to my oil-catching sponge
under the engine. No big deal.
4) Dug out thermostat. Boiled in pot on stove with candy thermometer purchased at small dry-goods store on island. Seemed to work fine.
5) Scraped old gasket off with razor blade.
6) Took paper and made tracing for new gasket.
7) Using razor blade, cut up Cheerios box in shape of new gasket. Smeared
liberally with silicone jelly (the stuff that stays liquid, not the stuff that
sets.)
8) Reassembled.
9) Tested engine. Engine still overheated.
10) Figured I must have installed thermostat upside-down.
11) Repeated steps 1 - 8. Getting pretty good at cutting up Cheerios boxes.
12) Tested engine. Engine still overheated.
13) Had a beer or two. Pondered.
14) Took off "radiator" cap and put candy thermometer in coolant.
15) Ran engine. Thermometer didn't match the engine panel. Engine not really
overheating after all.
16) Had another beer.
17) Ignored problem for one year.
18) At a hunch, disassembled and cleaned all electrical connections – sensor
and gauge.
19) Now engine gauge no longer indicates engine is overheating.
What I learned:
a) Corroded connections can make the gauge read HIGH. This is not at all intuitive for me, but that's what happened.
b) Cheerios boxes make pretty good coolant gaskets. (It's still there two years later).
Charlie May 2005
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Charlie makes a good point: In my experience a bad ground connection will make a gauge read high, and a lost ground will make a gauge peg high.
Frank Timmons V42 Magic Dragon Deltaville, VA May 2005
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Thanks for the responses. The noise actually sounds more like a metallic fan blade hitting something solid, i.e. ping noise. Boat would still go into gear, but didn't want further damage-sounded bad.
From what I gather, the engine and
transmission will have to be pulled together, and I will have my work cut out
for me, even if the marina does most of it.
Any other advice? (no, a new boat is
not an option) :o)
Mark s/v Querenca, T37 May 2005
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Don't know what engine you have. I have a Yanmar 4JHE on my T37 and there is (was) a "squirrel cage" fan mounted on the flywheel. The screws attaching this fan worked their way out and sent the fan crashing around that space in the bell housing, ultimately breaking up into pieces, jamming the flywheel, bringing the engine to a sudden stop (14 miles out of Acapulco, middle of the night, no wind). The description of your noise made me think of this and cause me to reply for the first time (long time lurker). Repairs were effected without removing the engine. The mechanic pulled the transmission back enough to remove metal pieces. Told me I really didn't need it (or stay there long enough to get one shipped in). I've been running without it since 1995. BTW, repair was effected with the boat in the water.
Ralph Gagliardi, T37 Brendan's
Watch, #526 May 2005
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Ralph,
I have a V-42 (1988) with a Yanmar
4JHE and had the same experience with the fan breaking apart inside the
flywheel housing jamming the flywheel and the engine stopping abruptly.
Fortunately for me I was only about a mile from my dock. My engine was repaired
the same way but a new fan was reinstalled (with the boat in the water).
Michael D. Lieberman May 2005
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About 2 years ago, I published a study on my Perkins overheating problem in my T-42. The solution I found to work the best was to add a second heat exchanger. I did some calculations from my Thermodynamics classes back in College and determined that the Bowman heat exchanger is 50% undersized. My Perkins developed an oil leak into the coolant system last summer, so I now have the FINAL solution to the overheating problem, a new Yanmar 4JH3-TE engine. I can now cruise at 7.0kts at 3/4 throttle too.
Best Regards, Salty Doug June 2005
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For all you 4-108 owners out there, here are some great overhaul pictures and accompanying details from Rod Lawson. Thanks Rod – excellent information! http://www.westsailor.com/
then
click on Articles.
James #451
From Rod:
James, I noticed your post on the Tayana
board. I couldn’t post a reply as I’m not a member and hope you don’t mind me
contacting you directly. I have a 4108 in a Westsail 32. I recently went
through the whole overhaul project (including replacing the rear main seal
which leaked badly) and posted a step by step pictorial on my website.
www.westsailor.com You will find the article in the section titled “Articles”.
Feel free to take a look and hopefully it might help you out. Feel free to post
the link to the site as well.
Fair winds....
Rod
Lawson
S.V.
El Viajero
Brisbane, Australia, web: www.westsailor.com June 2005
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