Heat exchangers

[alibaba.e]

Is it necessary to have a heat exchanger for the engine oil as there can be a problem with sea water getting into oil. For Perkins 107 engine.

[SkiprJohn]

It is not necessary to have a heat exchanger. There are many engines that have intake water cooling. The problem with direct saltwater cooling is that salts and corrosion build up in the cooling passages in your engine and eventually will cause overheating problems.

I can't remember how the Perkins engine is designed but I'm certain it could be bypassed. I'm not certain why you would want to do that instead of repairing the exchanger if it is allowing water into the oil.

kind regards,

[alibaba.e]

Thank you for information. I actually don't have a problem but my brother has had it happen twice in Mexico. Have heat exchanger on engine coolant and transmission.

[forsailbyowner]

I read somewhere, probably on this forum, that the oil cooler had a hand in contributing to engine sludging and plugging of oil passages.

[alibaba.e]

I believe I was not to clear originally. The heat exchanger I was considering removing is just the one for engine oil cooling. The engine coolant and transmission heat exchangers will remain on. The engine is fresh water cooled and raw water only cools the heat exchangers and exhaust system.

[onestepcsy37]

i have wonderful news for you. you don't need the oil cooler (heat exchanger). and this according to the perkins 4-108 shop manual.

the 4-108, as you probably know, was not specifically built for marine service; most of them went into farm tractors like your massey ferguson and other industrial/agricultural applications, where heavy loads are more common and more continuous - like pulling a five shoe plow through 640 acres of canadian loam.

perkins workshop manual, 4.108m series, page m-8;

" where engines are operated under light loads or at low speeds, which can result in sludging of the lubricating oil, the oil cooler can be removed or bypassed on 4.108 low line engines providing the raw water temperature does not exceed 100 degrees F and that the engine speed does not exceed 3000 rpm. later 4.108m lowline engines are not fitted with lubricating oil coolers, as tests have shown they are not needed. "

by the way, raw water temperature refers to the sea water around the boat, so unless you're sailing through a volcanic eruption with ash falling all around you, or maybe through a hot spring, it's probably ok to bypass the oil cooler...

[perchance]

I wouldn't be in too big a hurry to ditch the oil cooler. Pushing a big boat at hull speed doesn't qualify as a light load or low speed. Besides lubricating the engine the oil also extracts heat from the engine.
A tractor's oil pan is exposed to air flow whereas an engine down in the bilge is not so the oil in the pan can get quite hot.
If you toss the heat exchanger and see your oil pressure dropping at operating speed you will see why the exchanger is necessary.

[onestepcsy37]

fwiw, i push my 10 ton cutter with a 4-108 at hull speed at 2000 rpm. if you need to push a 4-108 to 3000 rpm you almost certainly have either the wrong prop or too small an engine. and never a sign of overheating.

since i normally run at 1700 rpm, i think i should be more concerned with the lube oil being too cold rather than too hot.

i tend to believe the engine manufacturers' recommendation, in the absence of any real proof to the contrary....

[David M]

Call the manufacturer and find out why it originally came with an oil cooler. Oil coolers do make Diesels last longer, for two reasons, the engine parts run cooler and the oil does not break down as soon. You can run a Diesel without a cooler if you dont care about those things. Good oil is critical for a Diesels longevity.

[perchance]

Boat and engine manufacturers do not add extra bits and bobs to an engine out of the kindness of their hearts,they are there for a reason

[onestepcsy37]

i'm not in the mind of perkins, but from their statement it's pretty obvious.

they start out by making one engine and try to sell it across the whole range of users. they eventually discover that in certain applications the engine could be 'tweaked' to better suit that particular use. so they make those changes to keep up with the market. for the 'm' series they find they can save a few bucks by deleting the oil cooler (but probably don't drop the price).

having worked in manufacturing most of my adulthood i can see life from their viewpoint. i started out programming cnc machines to make 750lb bombs for the air force during vietnam, eventually turned my life around doing programming and systems design for companies that made medical instruments - automated lab analyzers, kidney dialysis machines, heart pacemakers.

in any case, i have no intention of removing my oil cooler, mainly because i can't see any great need to. however, if one day it springs a leak i would have no reservations about plumbing around it, thanks to that little blurb in the perkins workshop manual.

ok, now i'm unsubscribing from this thread. i've said my piece, you've said yours, and we'll just have to agree to disagree....