Oldsmobile 5.7L and 4.3L V8 Diesel Engines

[S2500Dog]

Hey everyone,

I would like some history and infomration concerning the Oldsmobile Diesel Engines built during the laste 1970s into the the early 1980s. I heard Caterpillar came in 1984 and 1985 to help GM make their engiens reliable but unfortunately the devastating effects was already done in the society and in the market altogether.

 

[gmchevroletruck]

Was Detroit Diesel involved at all in those diesels you mentioned above, in the initial design? The reason I wonder about that, is that supposedly Detroit Diesel (used to be) an affiliation / spin-off company of GM years ago and is no longer now. Wonder if they were involved in the production of those, or design? If so, it would seem that the influence was much more from GM itself than from an outside source, as evidenced by the fact that they chose to use an existing block (although strengthened) as a starting point, rather than a total redesign, but that may have been more of a cost saving measure than a sign of ignorance, if you will. I'm not even sure they were bad engines, I've never had one or operated one of those. Seems I've heard that part of the reliability issue with them was lack of consumer understanding of the diesel product and procedures, and lack of proper dealer servicing, but that's old gossip, may not be true.

I do know that many a 350 diesel block has been salvaged and used as a great starting point for a high-compression, high-stress racing motor, due to their added strength

 

[S2500Dog]

Detroit Diesel did not have any involvement with these engines. It actually was Oldsmobile and Cadillac who designed these engines from the basis of the 350 Gas V8 engine through their engineering department.

 

[Fazzone]

I used to be really big into olds stuff, and looked into the 350 diesel. From what I can remeber, and I could be wrong, it looked like they bascally took a gas 455, and made the bore smaller, and upped the compression. I know they used the same size rod and main bearings as a 455, just don't remember what else was the same. I wanna say they had issues with the heads not holding up to the extra pressure. One of our neighbors had one and never had any issues, but the design wasn't cut out for a car of the time. They were noisy and smoked like a semi-not too appealing for a "nice car."

 

[Chris142]

I think much of the problems with these engines were driver error and lack of proper oils.

And that they were a very light duty engine didn't help any.

How many owners never read the owners manual and ran 10w40 in these instead of what was recomended? How often did they get a huge shot of either on a cold morning instead of waiting for the glow plugs to heat up?

IMO these engines would last much longer today with todays diesel oils and more educated diesel owners.

 

[Kruse]

Originally Posted By: Chris142
I think much of the problems with these engines were driver error and lack of proper oils.

And that they were a very light duty engine didn't help any.



Most of the repairs were head gaskets and the repairs involved a stronger head bolt.

 

[fdcg27]

The irony is that Mecedes showed the way, and GM ignored their lead.
The MB passenger car diesels of the same era were among the most durable powerplants ever put in a car.
They were also, of course, among the most underpowered, although Mercedes later fixed that with a turbo.
Had GM invested enough to design and develop real diesel engines, we might all be driving turbodiesels today.
GM didn't, and took the cheap way out, giving diesels a lingering bad reputation in the US.
The roots of GM's decline run long and deep.

 

[-Clayton-]

From what I understand some issues came from not having a water separator. They can be made reliable with the right stuff.

 

[SecondMonkey]

Problem is they're rated at what, 120hp? And don't even think about a turbo. I didn't know they made a 4.3 version, that must really suck. I have a '79 truck that could have had that engine as an option, I think 79 and 80 was the only years they ever put it in trucks. Then they came out with the 6.2, which doesn't have a lot better reputation...

The problem is they took a standard 5.7L and 4.3L gas block and said "lets make it diesel". The block was never engineered for that kind of service, neither was the crank, and the CR was just way too high for it to handle.

 

[Fazzone]

Just looked it up, they were rated at 105-125 hp and 200-225 ftlb depending on the year. Even the 307 which was pretty gutless had more power.

 

[GMBoy]

I agree that these engines were a rather poor excuse and were rushed to production. A bad move on GM's part for certain. A bad reputation for reliability followed shortly afterwards. However, even though these were not the best designs it also was introduced to the American Public who knew nothing of diesels and their uniqueness and maintenance requirements. I think stupid owners made the issues worse than they had to be.

When I was young, our neighbor bought a brand new Olds Delta 88 Royale - 1978 model with the Diesel 5.7 - new that year. The guy paid attention to that car, maintained it and had NO trouble whatsoever. He added a 1981 Pontiac Bonnevile, also a Diesel and ran both these cars up to around 1996. He then bought a Mercedes diesel because that's really the only diesel available that met his needs - the Jetta and such were too small for his needs.

My father bought a new 1984 Cadillac Seville Diesel and he mainatined that car with SAE30 - I even remember the bottle - Castol GTX HD30. He also did regular maintenance. He kept that car until 1993 when he bought a Deville (gas of course). The neighbor (same guy above!) bought that seville and still has that car today...but sold othe others.


Oh that Seville may have only had 125hp - BUT THE TORQUE was awesome! Would light the front tires up at will and felt responsive. Not sure what the top speed was because the digital spedo would just flash past 85mph...LOL!

 

[carlprop]

My Dad had a 1980 Chevy truck with the diesel. 2 years later he converted it to a gas engine as many others did. I remember the Kelly Blue Book at the time listed "deduct $1000 if diesel equipped".

 

[SecondMonkey]

Originally Posted By: Fazzone
Just looked it up, they were rated at 105-125 hp and 200-225 ftlb depending on the year. Even the 307 which was pretty gutless had more power.


Yeah, and the 350 gasser from the 70s is around 175hp/300tq. That shows what a failure of an engine it was, same displacement, same block more or less, and the DIESEL had way less power than the emissions neutered gas engine. Probably not much better mileage either, since it would have to work so hard to get a heavy 70s Chevy up to speed...

 

[eljefino]

They put the 4.3 in cutlass ciera FWDs. That car would have been awesome in snow, with all the weight!

 

[OVERKILL]

Originally Posted By: eljefino
They put the 4.3 in cutlass ciera FWDs. That car would have been awesome in snow, with all the weight!


Yup, my BIL's parents had one. It was a good little car. Stunk though.

 

[AntiMatic]

Got anything you want to run against my 72 Cutlass Supreme Convertible, 350 (gas of course), 4 speeed Muncie, 3.23 rear? BTW, the 350 diesel block is NOT the same as the gas, and can be bored and stroked to the magical displacement of 442ci.

 

[SecondMonkey]

Originally Posted By: AntiMatic
BTW, the 350 diesel block is NOT the same as the gas, and can be bored and stroked to the magical displacement of 442ci.


Never said it was the same...but almost the same...that's why so many of them blew up.