Originally Posted By: SLCraig
Im sure the fact the big truck Diesels are 10x the mass of a gasoline engine alone, that has something to do with it. Pistons the size of a small dinner plate..
Ive worked on some bigass engines (I have training as a truck mechanic) and the sheer size and materials used are definitely a factor in the longevity of the big diesels.
I learned to do a top end set for example on a CAT 3406. The engine is something like 3,000 lbs. Engine hoist and heavy chains to remove the cyl. head.
I really just assume that this is a factor in why they last for so many miles...
That is a small diesel engine. Locomotive engines are medium sized. Ships' engines (100,000+ hp) are big diesels. I can get my head & shoulders in the crankcase access ports on a medium diesel. I get into the cylinder with a ladder in a big diesel and get into the crankcase with a crew of men. We use chain hoists to lift bearing shells and gantry hoists to lift 7-ton individual cylinder heads.
The loads inside diesel engines are higher than inside gasoline engines. Thus the need for stouter engine construction and more robust oils, plus the contamination from soot, acid, and the need for longer drain intervals.