Volvo : when to overhaull

[Ottawacruiser]

I'looking at a 1998 boat powered by a Volvo TAMD-41P which has 3700 hours. I do not know much about diesels. Should I expect to have any major maintenance in the near future? If so what kind of maintenance? How to determine that it is time for overhaul or rebuild?

Thank your for your help.

[a64pilot]

You overhaul usually when oil pressure gets excessively low, (unusual) or when it uses an excessive amount of oil, or when it takes starting fluid to get it going cause compression is so low. (More likely)
I'm not being sarcastic here, but that usually between 2,000 and 10,000 hours, depending on how well it was treated and how good the engines design is, some are better than others and I'm not familiar with these.

People are going to pop up here and tell you to get an oil sample, but I do not believe you can tell anything from one oil sample. You can tell if an engine is on its last legs bottom end wise from inspection the oil filter though.

Generally if it has good oil pressure when the oil is hot and it starts like your car and has no blue smoke that doesn't dissipate, it's usually a healthy engine.
You may need an oil pressure gauge to tell oil pressure of course.
Often a well maintained engine looks well maintained, if it's clean, not dirty and has no oil leaks, unless a Perkins it's usually good.
Dirty and rusty? Unlikely to have been maintained well.

[model 10]

Yeah, what he said. Oil samples are a joke if you just do one. The oil filter and compression are the things to check. However I would not let anyone check my compression. The chance of breaking a fuel line and needing all new gaskets are not worth it me. And I don't think an engine that looks like **** could be thought of as a good engine. It might be, but only by luck, not good maintenance

[Ottawacruiser]

Then what would be a normal low and high oil pressure?

[model 10]

Would not worry about high oil psi but low can be pretty low. I've had warranty problems with very expensive engines with low oil pressure. The dealers would say you can have like 20psi and it's all good (BS!). You do need a a good oil pressure at idle, not like 5psi or something. I would say at least 25 at hot idle would be OK. It really should hit the relief valve at max rpm cold, so that would be spec oil PSI.

[Ottawacruiser]

Is there such a think as an engine survey?

[DumnMad]

Deisel injectors/fuel pumps overhaul are a much more likely requirement at those hours.

[belizesailor]

Originally Posted by Ottawacruiser

Is there such a think as an engine survey?

Yes. General inspection by a pro mechanic. Compresion check. Oil analysis (though better when done regularly to spot trends, but a one shot analysis can give you some indicators of internal health).

[belizesailor]

Originally Posted by Guy

Yeah, what he said. Oil samples are a joke if you just do one. The oil filter and compression are the things to check. However I would not let anyone check my compression. The chance of breaking a fuel line and needing all new gaskets are not worth it me. And I don't think an engine that looks like **** could be thought of as a good engine. It might be, but only by luck, not good maintenance

Yeah, could break something doing a comp check. An engine that looks like s...t probably has not been well maintained. Personally, Im more comcerned about cleanlyness of my engine rooms than the galley.

[belizesailor]

Originally Posted by Ottawacruiser

I'looking at a 1998 boat powered by a Volvo TAMD-41P which has 3700 hours. I do not know much about diesels. Should I expect to have any major maintenance in the near future? If so what kind of maintenance? How to determine that it is time for overhaul or rebuild?

Thank your for your help.

3,700 hrs is just broke in good. Do you know if the hour meters are accurate?

[a64pilot]

Originally Posted by Ottawacruiser

Then what would be a normal low and high oil pressure?

That should be in the engine manual, but what I look for is say an engine that the oil PSI is 50 at idle when cold, and when hot it may drop to 25 or so but jump back up to 50 or so with cruise RPM when hot. High idle when cold should tell you oil pressure relief valve setting and I want it to run close to that when hot under cruise RPM.

Don't put anything into those numbers as absolutes, it could be 60 or 35 depending on engine.

But what I do not want to see is 50 when cold and 10 when hot and won't get past 25 when hot at cruise RPM, that indicates excessive clearances in the bearings.
However usually it's the top end that trips an overhaul as in low compression and excessive oil consumption. Usually only see bottom end problems if someone just never really changed the oil and or ran regular gas engine oil or something.

Maybe I put too much in cleanliness and neatness, but I've never seen a well kept engine that wasn't clean and orderly with no jury rigs.
Now real boat engine guys are the big powerboats, and you have to see those engine rooms to believe them, cleanest, most well lit room in the boat. That is the standard to strive for.

[Lepke]

It would be worth your effort to find out how the boat was operated. That engine is rated light duty commercial. Full power (3800 rpm) is only supposed to be used 2 hours out of 12. The other 10 hours should be at least 10% lower rpm.
Also, it's a turbo equipped engine meaning high Exhaust Gas Temperatures. High EGTs eat away at all the cylinder components. Especially rings, valves and cylinder walls/sleeves. In engines run too often flat out, overhauls usually start at 2500 hours. Engines run at 80% of hp or lower usually make 7000 hours. A non turbo version of the same block can usually make 10,000 hours if cared for. Clean oil also makes a big difference.
a64pilot covered what to look for. If you don't know engines, you need a good mechanic with Volvo experience to survey it.

[model 10]

Originally Posted by a64pilot

Now real boat engine guys are the big powerboats, and you have to see those engine rooms to believe them, cleanest, most well lit room in the boat. That is the standard to strive for.

I think they are much better designed engines. I overhauled our Perkins using good glue and I see oil leaks after 200 hrs.

[jimbunyard]

The TAMD41 is a good engine, made in-house by Volvo, though parts tend to be very expensive.

Well maintained, a very rough estimate would put the engine at 1/3 to 1/2 its life at 3700 hrs, providing the engine was propped correctly and run within the parameters specified by Volvo for the engines duty cycle rating...

200 hrs per year would be a low normal for a primary propulsion engine in a pleasure boat, ideally the hours would be spread out over the year, but a boating season/layup yearly schedule wouldn't affect the life of the engine very much.

Idle periods of 2 years or longer, without proper mothballing could, however, substantially shorten engine life...

The best tools for determining the condition of the engine are your eyes, ears and nose.

While I'm not quite as concerned about appearance as many, it is more likely that an engine that appears well maintained is well maintained (and that doesn't mean just a fresh coat of paint). Ain't necessarily so though...

If the engine starts quickly (with this engine, with ambient temps above 70F, from cold, without glowplugs, about three-four seconds), runs smoothly, accelerates (fairly) linearly (on my 41B there is a distinct surge at about 2600-2800 when the turbo kicks in), doesn't smoke (a small amount of light gray on start-up, especially when cold, is normal), doesn't knock from the lower end (crankshaft area), and has good oil pressure at idle and operating speed (mine is 30-35 lbs idle, depending on temp, and 55 at speed) and doesn't overheat (with ocean temp at 85F, on a hot day, normal for me is 190F at speed [3400RPM]), you shouldn't have to worry.

If any of those things change, then you start troubleshooting...

One problem that is common for Volvo engines of this era are issues with the electrical systems. At almost 20 years old you may experience problems related to the gauge panel, multi-pin connectors on the engine or in the wiring harness between the engine and the panel. In my opinion this is because Volvo used undersized wiring in the harnesses, which lead to heating within the connectors, which lead to shorts within those connectors.

I just made a new panel with Teleflex gauges and my own engine wiring harness to circumvent the problem. Changed the alternator to a Delco and the starter to an aftermarket gear-reduction unit instead of the old direct drive one from Volvo (Prestolite I believe).

[Ottawacruiser]

Apparently ok. The boat is 1998.