Ah, I remember those things! The WERE a redesign of an existing
gasoline engine (not a converted one, but based on existing designs),
and on top of the problems you describe they had a distressing
tendency, at least in the early ones, to spin a rear main bearing every
25,000 miles or so. I remember considerable problems with head cracks
too, but that's not exclusive to the Olds design by any stretch -- most
manufacturers of pre-chamber diesels have head problems until they work
out how to keep the stresses controlled. Benz had horrible problems in
the 60's when they took over the design from their original supplier.
They also suffered from catastrophic IP failure due to inadequate fuel
filtering (in those days, most diesel equipment had twin filters AND a
settling bowl) and owner ignorance of the need for constant fuel filter
inspection. Doesn't take much water to bash the IP, and you are
correct, the quality of diesel fuel in those days was deplorable.
Interestingly, they DO last almost forever when you get a good one -- a
friend of my old boss had one with 200,000 miles on it -- basically a
Oldsmobile Cutlass "replica" made of rust and pop-riveted sheetmetal
with a decent diesel in it. I've also heard the do very well in
constant speed applications (irrigation pumps, for example), running
for decades of use.
GM had mountains of engineering problems during that era, mostly due to
non-engineers monkeying with the design work (as in substituting head
bolts to suit equiment that wasn't ever going to work -- Roger Smith
had decided to use robots instead of human workers). The aluminum
block in the Vega was a perfect example -- Benz still uses the
technology, and it works wonderfully. GM botched the actual production
design by "cheaping" it to death -- to say nothing of the horrendous
quality of the body.
The Olds diesel had a couple of problems that became insurmountable --
bearings too small and very low power for the displacement -- it should
have produced around 300 hp and 500 ft/lbs of torque (with a turbo, of
course) -- unfortunately, I don't believe the engine as it was built
would hold up with a turbo.
Otherwise, not a bad design -- timed injection (a rarity in US
manufacture, even today) and a wide enough rpm band to put in a car
with a normal tranny. Too bad GM didn't bother to finish the work on
it....
Peter
