GM 4.3 V6 Diesel

mminerbi

While the problems of the GM V8 diesel used in cars is legendary, little has been written about the V6 diesel that GM offered as an option in the '82 - ~'85 model years. Does anyone have any history on this engine? Was it a gasoline conversion to diesel, like the V8? Was it as problematic as the V8?

andre1969

...but I think all the 4.3 was is an Olds 350 with two cylinders lopped off, in the same fashion that Chevy made V-6'es like the 200, 229, and 262...they were just corresponding 267's, 305's and 350's with 2 fewer cylinders.

There never was a gasoline version of the Olds 4.3 Diesel. I don't know about reliability, but I can't imagine that it would be any more reliable than the 350, but would have the added problems of less power and a rough idle.

mminerbi

I believe the Chevy 262 was a small displacement V8 that was untroduced as a response to the second oil shortage (of course, it wasn't a bona fide shortage).

badgerpaul

You're right there was a 262 V-8 in the mid 70's, it was an option in the Vega inspired Monza. But the current 4.3l V-6 in Chevy/GM trucks also has a displacement of 262 ci.

andre1969

I forgot all about that one! I think there's a lot of confusion because of not only that one, but then Chevy had the 4.3 (262) V-6, which they still use, but then for a few years they also had a 4.3 V-8, that was the base engine in the Caprice from 1994-1996. I don't know the CID displacement of that particular engine, though. The Chevy 267 of around 1978-83 vintage was actually a 4.4 liter, I think.

I always wondered why Olds didn't try making more V-6 variants of their V-8 engines, like how Chevy and Buick did. While Buick's 231 didn't have an exact bore/stroke matchup to any Buick V-8, I think it did have the same pistons as a Buick 350, but just had a shorter stroke. And then Buick had a 3.2 variant in the late '70's and 3.0 and 3.3 in the '80's/90's. Oh, and a 4.1 version too, that ran from '81-84, I think.

It would've been kinda neat if Olds had V-6 versions of the 260, 307, 350, and 403. The corresponding V-6'es would be 195, 230, 262 (which we did have, but only as the Diesel), and 302. Although I guess a 302 might've been a bit big for a V-6!

spokane

Hello Maury,
I had forgotten about the 262-V6 diesel but do recall a diesel that appears to have been even less popular. For '79, Olds "dieselized" their 260-V8 and offered it in the Cutlass. I drove one of these 90 HP cars and considered it to be badly underpowered. Even though the 350-V8 diesel was rather popular at that time, I had the impression that very few people wanted the 260 diesel. Since even the gasoline versions of this engine didn't measure up to the "Rocket V8" reliability reputation, I suppose the small diesel must have been an even worse failure - both technically and in sales - than the 262 and 350 diesels.

mminerbi

Thanks for the reminder about the smaller V8 diesel, Spokane. Correct me if I'm wrong, but the 260 c.i. V8 was optional on some GM rear-wheel-drive Intermediates, such as the Olds Cutlass Supreme, while the V6 was for use in certain front-wheel-drive models only. Examples of models where the V6 diesel could be specified included the Olds Cutlass Ciera and the newly downsized 1985 front-wheel-drive Olds 98.

Do any readers have information about the reliability of the V6, given that it was introduced after GM engineers had received feedback about the problems experienced by the owners of the V8 diesels? There doesn't seem to have been much written about the V6 diesel, but that may be because the number produced was low. It's also possible, though perhaps unlikely, that the owner experience was considerably better than that of the V8 diesel owners.

andre1969

...the 260 Diesel V-8 might've been a bit more reliable, since it was the same block with a smaller bore, so I'd imagine the cylinder walls were thicker. Unless, that is, GM found a way to cast them thinner in correlation to the smaller cylinders, which I wouldn't put past them ;-)

I'd forgotten they even made a 260 Diesel, although I've seen the gasoline version in a few different cars over the years. Awhile back, I test drove a used '78 or so Cutlass Supreme with the 260 V-8. I had an '82 at the time, with the 231 V-6, and wanted to see if the 260 felt any faster. It didn't. A good friend of mine used to have an '82 Cutlass Supreme sedan with the 260 V-8, and it actually felt pretty quick by comparison. I looked up the stats on it and found that it only had about 100 hp that year, although I don't know the torque. It didn't feel that much slower than the '86 Monte I was driving at the time, which had a 150 hp 305 and a 4-speed automatic. One thing I noticed though...I've never seen a 260 V-8 in anything other than an Olds product, while it seemed the other engines were often swapped across the board. Did the 260 ever find its way into other GM products?

As for the 4.3 V-6 Diesel, I haven't heard much about it either, except to avoid it. Still, it doesn't have the bad rap the 5.7 did, probably because they made a lot more of the 5.7, so there were more owners to complain! In addition to cars like the Ciera and FWD 98, I think the 4.3 V-6 diesel was used in the RWD intermediate lineup as well, in cars like the Cutlass Supreme, Bonneville, etc.

One thing I've always wondered, too...did the Olds Diesel engines ever improve in reliability over the years? I know in general they say to avoid them all, but I'd like to think that GM at least addressed some of their problems over the run of that engine!

mminerbi

Andre, I believe the 260 Rocket V8 (I'm not sure it was labeled "Rocket", but we seem to agree that it was a Rocket engine derivative) was used exclusively in Oldsmobiles.

The '78 Cutlass Supreme, with the 260 gasoline V8, that my family and I drove from Chicago to Ft. Lauderdale, was pleasant and adequately powered up to 60-65 mph, but beyond that speed acceleration was quite slow. That Cutlass was a new "drive-away-car"; that is, we got free transportation in return for delivering the car to its destination, for use in a rental fleet. Compared to the 305 (Chevy) V8 in my '78 Pontiac LeMans, the LeMans was faster, particularly at higher speeds, but the Olds 260 felt somewhat more refined (quieter and smoother), if that term is applicable to cars of that era.

andre1969

...I thought that Diesel engines usually put out an incredible amount of torque, compared to their gasoline counterparts. But I saw some stats on the Olds 350 Diesel, and it looks like it only put out 200 ft-lb of torque!

What's going on here? An Olds gas 350 was usually good for 160-170 hp or so in the late '70's, although I don't know the torque rating. The 307 had 255 ft-lb, so I'd guess the 350 was around 280 or so. In contrast, the Diesel only had about 120 hp in the earlier versions, and 105 in the later. Why are they so wimpy in the torque department, though?

And if the 350's torque rating is only 200 ft-lb, it makes me wonder how sad the 260 and 262's were!

mminerbi

Andre raises an interesting point concerning the relatively low torque of the 350 diesel. To that point, perhaps the high torque he attributes to diesels applies to turbo diesels, but not to naturally aspirated diesels. After checking a couple of European brand websites for European countries where auto diesels have significant market penetration, it's not clear to me that naturally aspirated diesels generally have more torque than naturally aspirated gasoline engines of the same displacement and confguration. The fact that turbos are more common among diesels than their gasoline counterparts from the same manufacturer suggests to me that, in addition to generally having less horsepower, this relative diesel deficiency is not offset by higher torque.

The recent adaptation of direct injection technology to many diesels, naturally aspirated and turbo, further complicates current diesel/gasoline comparisons since, in addition to a fuel economy advantage, direct injection can also offer a performance advantage over non direct injection diesels. Of course, direct injection doesn't apply to engines from the late '70s/early'80s.