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Old 06-10-2019, 03:36 PM
jz78817 is online now
Join Date: Aug 2010
Location: Under Oveur & over Unger
Posts: 12,338
Originally Posted by WildaBeast View Post
Diesel cars had a brief period of popularity in the US in the early 1980s in response to the fuel spikes of the 1970s, and during this era Detroit made some diesels that were complete garbage. As I understand it Oldsmobile had one that was notoriously bad, precisely because GM failed to design it to handle a diesel's higher compression ratios (I think they might have simply modified one of their existing gas engines to burn diesel, but I might be wrong).
you are wrong. the Olds 5.7 diesel shared almost no parts with the gas engine. it was built in the same plant so certain aspects of it (bore spacing, deck height, cylinder head bolt layout) had to be the same, but apart from that the diesel 350 and gas 350 were almost entirely different engines. The two flaws it had were 1) weak head bolts causing blown head gaskets, and 2) the lack of a water trap in the fuel system which damaged injection pumps and could contribute to blowing head gaskets.

IMO the diesels from this era gave them a bad reputation in America. But most European car companies are more skilled at building reliable diesels since they've been doing it longer -- see the legendarily indestructible Mercedes 300D.

Yes, you do have a point about the emissions control devices, though.
the only thing the OM617 has in common with a modern diesel engine is they notionally burn the same type of fuel. those old engines were so durable because they made practically no power and were really understressed. The modern OM624 V6 is known to have several weak points, as does the VM Motori 3.0 V6 used in several FCA vehicles. High pressure fuel pumps are a weak point on a lot of engines.