Originally Posted By: OVERK1LL
As for GM, I cannot see how one could expect that putting diesel heads on a 400 small block was going to work out well in terms of reliability. And go figure, it didn't.
Well, it wasn't a 400 sbc that they sarted with- those couldn't keep their head gaskets in one piece even on gasoline! They at least had the sense to start with the Oldsmobile 5.7 (350), which was probably the most rugged GM-built v8 at the time, instead of the much more lightly-built smallblock Chevy. But even the Olds wasn't up to just slapping some 15:1 heads on it and expecting it to live. Truth be told lot of its problems were actually more fuel system related than directly engine-related, though. The cars that got the OldsmoDiesel back in the early 80s didn't have water separators and better/larger fuel filters that are needed for diesels, and then low-and-behold injectors and injection pumps started failing left and right. That would be OK if it just caused a cylinder to drop off line or the engine to quit- but with a diesel that's not the only failure mode. For example, it doesn't take long to wreck a diesel engine when one injector is always firing 30%-50% more fuel than all the others- kinda like beating that one piston with a sledgehammer every other turn of the crank, even at idle :-( But there were plenty of engine related problems, too- cracked heads, broken head bolts, etc.
The one I didn't understand was the 6.2. They *knew* the deal by then, had been burned by the OldsmoDiesel, had a chance to make a great engine, and made a mediocre one instead. Sure, it was far better than the 5.7, but it still couldn't hold a candle to the old normally-aspirated Navistar diesel that Ford was using. Then when Dodge put the Cummins B5.9 in the Ram, everybody else was playing catch-up for years.
As for GM, I cannot see how one could expect that putting diesel heads on a 400 small block was going to work out well in terms of reliability. And go figure, it didn't.
Well, it wasn't a 400 sbc that they sarted with- those couldn't keep their head gaskets in one piece even on gasoline! They at least had the sense to start with the Oldsmobile 5.7 (350), which was probably the most rugged GM-built v8 at the time, instead of the much more lightly-built smallblock Chevy. But even the Olds wasn't up to just slapping some 15:1 heads on it and expecting it to live. Truth be told lot of its problems were actually more fuel system related than directly engine-related, though. The cars that got the OldsmoDiesel back in the early 80s didn't have water separators and better/larger fuel filters that are needed for diesels, and then low-and-behold injectors and injection pumps started failing left and right. That would be OK if it just caused a cylinder to drop off line or the engine to quit- but with a diesel that's not the only failure mode. For example, it doesn't take long to wreck a diesel engine when one injector is always firing 30%-50% more fuel than all the others- kinda like beating that one piston with a sledgehammer every other turn of the crank, even at idle :-( But there were plenty of engine related problems, too- cracked heads, broken head bolts, etc.
The one I didn't understand was the 6.2. They *knew* the deal by then, had been burned by the OldsmoDiesel, had a chance to make a great engine, and made a mediocre one instead. Sure, it was far better than the 5.7, but it still couldn't hold a candle to the old normally-aspirated Navistar diesel that Ford was using. Then when Dodge put the Cummins B5.9 in the Ram, everybody else was playing catch-up for years.