PeachParts Mercedes-Benz Forum - a good engine,can't believe it.

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- - a good engine,can't believe it. (http://www.peachparts.com/shopforum/diesel-discussion/380997-good-engine-cant-believe.html)

Quote:

Originally Posted by BillGrissom (Post 3640894)

I read-up a bit on the 1970's GM diesels. They actually worked the bugs out after a few years, but by then their reputation killed sales. GM has always been innovative, but uses buyers as their guinea pigs, a problem of corporate decision-making not engineering.

There are many engines that have a long legacy and are very rugged. The small-block Chevy V-8 in the Corvette, Camaro, and trucks is a direct descendant of of the famous 1957 Chevy V-8 and still uses push-rods. The Chrysler small-block was hardly changed from 1964 thru the Magnum engines (~2002), so much so that some bolt Magnum heads to a 1964 block and/or swap transmissions. Their replacements are high-tech, but showing issues. I think Ford is similar. But, perhaps on the pedestal is the Jeep straight six (4.0 L) with a block from the 1950's. Jeepsters mourned its recent departure.

As far as rugged M-B diesels (OM617), there seem to be many small things that can take one out. One of the biggest is the loss of a few tiny bearings in the vacuum pump can cause parts to slide into the timing chain and cause mass destruction. My 1985 CA engine failed at 330K miles from unknown causes. I found 3 of the 5 pistons missing chunks. A mis-aligned injector can burn a hole thru the pre-chamber and piston. People have found the camshaft towers broken. But, the biggest downside is that they can't be rebuilt affordably, due to lack of parts. If you can find a new piston, they cost $550 ea vs $80 for a set of 8 for a small-block Chevy. Add that many other parts for the vehicles are "not avail" or exorbitant and there isn't a bright future for driving these cars. At his first job out of college, my son asked about a 1990's BMW 8 cyl on craigslist for $4000 that look nice (other than dented door). I told him that car probably had negative value, assuming just a few typical neglect issues like "no charging" and "no AC". I see people do absurd things to keep Euro cars on the road, due to over-priced parts, like one neighbor bought junkyard motor mounts for a Volvo. No sane Chevy owner would put used rubber on their car, since it all costs $5 and always on the shelf.

I got some used 85 pistons, ill take $295 each for them, customer must remove then from the block :D

panZZer, thanks for the offer. I have a set of used turbo pistons to rebuild my 85 engine, courtesy of Rollguy here, and an order of magnitude less than the new price. So far I just replaced the cylinder liners and have all the bearings and gaskets, but back-burnered since I got a whole engine off craigslist for $300 which turned out to be pristine (>400 psig all cylinders).

I see them for sale but havent got the nerve to deal in the 90s yet,still liven in the 80s and have no complaints.I have owned a few 190d 4 and 5 cylinder jobbers and they seemed needey as far as the unservicable lines and ,rubber orings?

I'm just going to through a OM602 + 5 speed in my wagon when my OM617A and 4 speed sing their final song. Not worth trying to rebuild a 617 with all the rare expensive components, and the lack of a cross flow head.

-Mike

Quote:

Originally Posted by vstech (Post 3639621)

Ugh..

Chevy did NOT turn a 350 block into a diesel...

GM sent the dimensions of the BOP big block to detroit diesel and had them design a diesel motor that fit in the chassis...

Unfortunately, the BOP big block uses 4 bolts per cylinder, and couldnt handle the pressures of the 22to1 compression diesel...

Mercedes never under designed their motors... tank production from day one...

Not quite.

Actually, GM started with the 350 Olds engine because it had a HUGE bottom end with gigantic crank pins and mains. They did add forged rods and cranks and for many years Olds racers looked for Diesels as a starting point for gas race engines (tough parts for not much $$).

Some confusion is understandable as GM made 4 separate and distinct 350 CID engines in this era. The Chevy, of course, is well known but the Pontiac was a de-bored and de-stroked Pontiac 389/421/455 - completely unique from the Chevy (no interchangable parts). The Olds 350 was essentially a downsized Olds 455 and the Buick 350 was a completely unique engine with NO shared parts from any of the above or with the big block 430/455 Buick engine. In that era one of the reasons you stepped up in the product line was that you were getting a Pontiac or Olds or Buick engine and the belief was that you were getting a better engine for your dollars.

It is true that Detroit Diesel "Dieselized" the Olds but there were untold compromises including a paltry 17:1 compression ratio, one of the reasons the darn things wouldn't start in cold weather. The Stanadyne pencil injectors proved unreliable in this application although they worked fine in other engines - I never did hear a reason for that but I suspect that the injection pump wasn't up to the task. And yes, the 4 bolts/cylinder was a HUGE issue.

So, (to quote Paul Harvey) "The rest of the story". At least, the part that I know. BTW - I owned one of those Diesels in a 1980 Chevy pickup which I drove from where I bought it to my shop and immediately replaced it with a 455 Buick.

Dan