If these engines were in a lorry...I wonder?

Were the engines overpropped: i.e. could they reach 3900rpms, and were they driving a heavier, slower boat ?

Now your talking. did the engineer just change both head gaskets and Turbos etc "to be on the safe side" nice quick and easy job and would give him the oportunity to have a look for anything else, and the cash, of course.

you will find that Volvo (and other manufacturers) tend to take a smaller diesel engine and make it produce more power by tweaking the bits attached, so the base engine is say, 80 BHP and they make it produce say, 100 ( just used as an example so dont flame me yet) with more air and more fuel and greater compression? If this is the case the extras maybe won`t stand the "pressure"

With the replacement of the Turbos, ensure that the oil "cool" feed ( pipes) to the Turbo bearings and all associated oil ways are fully cleaned out! otherwise the Turbos will go again. Also (and Im sure you know this ) don`t rev your engine before you close it down, as you deprive the turbo bearing of its oil supply and wear occurs. Re the 200 hours use, that is the equivalent of and earth mover working flat out for 9 days pulling 30 tons of muck. Not many hours on an engine is it.

Work your diesels and they will thank you by acepting the challenge and running for "ever"

Now and old Gardiner is another story, lovely engines!
 
Highly stressed engines have a short life, low revving sloggers have a long life. Traditional marine engines last for years, sports boat engines don't. It's a trade off between performance and longevity.
Having said that, high revving car diesels seem to last OK!
Perhaps boat engines have weaknesses built in because boat owners can afford to replace them regularly. After all, if you've got a boat you must be rich!
 
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Thats what i was going to say! If you have a fast boat with a pair of 600hp s you may well be crusing at half power quite offten?

But if you have something like a bertram 28 with a pair of Volvo 130 Hp you might intend not to open the throtel fully on a passage but after just very short while most will (me) be at full throtle (sounds great) and skimming along with 3400rpm and 20+knots!!!

Cars cruise at about 3200/3400 rpm as well that gives between 120kph and 140kph! Unless the car has a 6 speed box!
 
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er don't think you are saying the same thing as tcm at all - regardless of throttle setting/cruise speed etc other than at tickover and maybe a tiny bit more a marine engine is generally used under load (due to drag) in a way that a car/lorry simply isn't exposed to.
 
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quite so, makes no difference whether you have 200 or 2000 hp, the boat will always drag it down that much. No clutch, massive drag=full load all the time. Apparently it is this that causes most probs for diesel engine, and completely different fomr oodles of other diesel applications from power generation to lorries and the like, and of course mikefs issu of infrequent usage also an issue.
 
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Difference is. If truck engines broke or bits to expencive. They would stop selling overnight. Where as with boats and specially before tinternet, no one knew, or could nt tell others very easy. So crap OK.
 
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And calories...it has a lot do do with calorific value the the dissipation of heat thereof.

Old (and venerable) rule of thumb for a marine engine: No more that 1HP for every cubic inch capacity. So eg mine at 262 cu in the max HP is 262. The actual output is 205Hp, so all is Ok on load and heat dissipation. I could uprate my engines to 400Hp without much ado - but how long would they last?
 
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"infrequent usage "...... thats the point it has not been your typical boat sitting there for 4-6 months at a time unused, it has been used. But failure after just 500 hrs is not acceptable. My stb Head gasket did'nt go until 2500hrs, and the turbos are fine.
 
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no one seems to be acknowledging that this cannot be normal........I know how about a question ....."has anyone else had head gaskets go on KAMD43's and if so after how many hours?"
 
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propload.jpg


It's not quite as bad as "full load all the time". The upper (solid) curve is full load against a dyno at various revs. The lower (dotted) curve is some sort of "typical" (i.e. matches no boats whatsoever) prop load curve.

What this shows, is that with this engine, up to 3000rpms, you're not actually pushing out more than about 1/2 power, until the last 15%, where the power ramps up and gets much closer to that "max power" curve. It's no concidence that fuel consumption increases dramatically in this zone too.

Why I was asking about overpropping, was that the effect of running a too big prop will be to "push" the dotted curve up to be closer to that max power curve. Couple that with a heavy boat, where you might be running in that top 15% zone just to keep planing (or worse, semi-displacement), and whammo, your poor engine could easily be chucking out DOUBLE the power compared to a lighter boat using the same engine, correctly propped, running maybe a bit lower down the curve. Guess which head gasket and turbo is going to blow first...

dv.
 
general consensus seems to be that volvo,s no good, perkins no good, mercruiser no good. what can we use? My perkins m135 has done 900hrs with no probs at all.doesnt use any oil,Still its flat out at 2300rpm and is naturally aspirated so it should last a bit longer.
 
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Hmm, looking at the Sealine site, the 43's are the smallest engine option, and flat out, will only get 25-27kts. An F37 is 8000kg+ loaded, so previous comments about running smaller engines at high loads in heavy boats might not have been too far off the mark.

I'm still a bit surprised that both failed so quickly. My worry would be that the replacement gaskets/turbos etc. might have the same problem in another 500hrs.

dv.
 
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Sorry….

Cannot possibly comment as “informed” in this particular instance, but it does sound quite strange that both engines should develop same problem, and that the turbo packs in at the same time.

We’ve had and have experience with boats that have had SABB, Perkins, Fords, Volvo’s, OMC’s and now Detroit’s and have had the impression that most of the stuff have quite good and reliable, without any major problems. (not counting the MD32’s on a 32 ft planning boat). Then again, we have always been careful keeping an eye on the mechanics and not overloading the engines. Also very careful not revving turbocharged engines at start-up (fast spinning turbo and no oil or oil pressure is not a good combination). We have always let the engines work up to 60 – 70 C under load, before pushing the engines above 50% …. And have equally allowed the engines to idle for 5 minutes after running on high load.

Loads of things can go wrong with most engines, and yes some engines are more sensitive to in respect of tolerances than others… and in my subjective experience, the higher revving engines are more sensitive than the low revving ones.

So without knowing and understanding the usage pattern, how the engine is loaded, and how the user treats the engine, it is very difficult indeed to comment objectively. What I do know is that on faster planning crafts, there is a tendency of the users to have a bit of “get up and go” attitude… That could be start up (including revving cold engine), move out and push up onto plane with a cold engine, which is not beneficial for any engine in any configuration.
 
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