Hey all,

I want to start some discussion on the olds 350 diesel GM 5.7 engine.

This engine has the dubious credit of giving diesel engines a bad name in the domestic market since their inception. I've heard that poor reliability was the culprit. I've also heard that GM made them better before the end (too late) and that there are things that can be done to make these good engines.

I like the fact that they are based on a BOP engine and will fit into almost ANY Rear Drive GM product you could think of. I presume they are of lighter weight than a 6.2/6.5.

The downside I see is finding BOP transmissions suitable for a Diesel...but you'd normally find them as a pair I guess.

The 4.6 also falls into this topic. Were they FWD only, or did they come RWD as well...or can the same engine be used in either configuration?

My biggest question, is: What does it take to make one of these engines reliable?

Thanks,
Clem

Clem:

I do agree with you in that this engine has been given a bad rap and as such effected the reputation of automotive diesels in general. For a large part the reputation was well deserved as the earlier versions were notorious.

On the plus side, the General did rise to the occasion and the ones subsequent to 1981 (DX block) had most of the bugs worked out. After 81 the only real problems were head related. Interestingly enough, the 6.2 suffered from some of the same problems ergo cracking between the valves, head bolt stretching, head gaskets, etc.

The pumps (now manufactured by Stanadyne)continued to have upgrades to the internals as the original was designed for a tractor engine and the extended use in an automotive engine resulted in some wear and function problems.

In answer to your questions the only difference in the trannys was in the torgue converter and the govenor, both easily rectified problems though it will be much easier to find the Chevy based bellhousings then the BOC patterns. As far as fit is concerned, the 5.7 is only about 150 lbs lighter then the 6.2, but the 6.2 has a much wider application base then the 5.7 as it is based upon the standard Chev small block configuration.

Can it be made to be reliable? In a word "yes". The big question is do you want to. I spent almost 20 years doing what you propose but try as I might, either you built it to be reliable or you built it to produce power. The two seem to be mutually exclusive.

In my final attempt I installed a 5.7 with all the reliablility mods into a 1986 Cadillac (straight bolt in conversion) Fleetwood. Alone the engine was capable of moderate acceptability from a drivability point of view and gave incredible fuel mileage (40 plus MPG (Imp)) but it had absolutely no power. Would cruise all day at 70 MPH giving great mileage but as soon as you got into the hills it didn't have enough power to blow itself to hell. Passing? not a chance. Got four miles and a good stiff tail wind?

Making them reliable consisted of making sure you had a good set of crack free heads (hard to find) the last variant of head bolts properly torqued and double coolant lines from the back of the heads. The pump had to be set up right and the timing mechanism working properly and set up for no more then 120 HP. Other then that the bottom ends were bullet proof after 81 and the timing chain should be replaced every 70K just on spec. (better safe then sorry). Change oil every 3k, good fuel and you'll be all right.

The 6.2 makes for a much better conversion, though there are stilll some issues with fit, but the result is a much more tractable engine and much better parts availablility.

Hope this helps

Bill

Thanks Bill for that info.

I wasn't aware that they were so gutless. I was figuring they would underpowered...but not by that much. I guess that tells me what I need to know about the 5.7 and that, unless I stumble across one some day...I don't need to go seeking them out.

Thanks again,
Clem

I have a small collection of the Olds diesels, parts and cars.

The smaller engine you reference is the 4.3L. It came in a couple forms as a V6 and there was also a 4.3 V8 in '79 and '80.

The 4.3 V8 was used only in the A/G body cars (rear drive Cutlass and the like). The 4.3 V6 was used in those same cars begining in 1982 with cast iron heads. In the front drive A bodies (Celebrity/Pontica6000/Olds Cutlass Ciera/Buick Century the V6 used aluminum heads and the water outlet was to the rear of the engine (meaning a diferent intake manifold). The V6 was the most upgraded of the Olds diesels, but by the time it came out, gasoline supply and price had stabilized from the 1979 shortages and the early Olds diesels had aquired a rather bad reputation, thus the market pretty much dried up for the American diesel cars.

All the V6 variants are very rare today as are the 4.3 V8's. Any 4.3 V8 that had a warantee problem was replaced with a 5.7. I have a 4.3 V6 Cutlass Cierra and 2 of the 4.3 V8 cars, one still has it's original engine. The other was replaced with a DX 5.7 sometime during it's early life.

Parts and cars still turn up, usually cheap. I've been collecting stuff for about 8 years now and have enough parts to last a lifetime, including a couple brand new engines.

BTW, as an experiment on one of my 5.7 cars, I reused a cracked pair of cylinder heads with no ill effects. They commonly crack between the intake and exhaust valves.

Overall, I consider them worthy, although it helps greatly if you can work on them yourself. To have to pay someone would make it to expensive to be worthwhile. (even if you can find someone knowlegable to do the work)

I have a 1981 Chev Caprice Classic, looks real nice and drives out well. Diesel engine runs great once you get it started! I drive it a couple times a week, but after 70K miles and all the expenses on keeping the engine running, I'm just proud as I can be that I can still get in it and hear that diesel engine clatter. It is cool to pull into a fuel station and have everyone look around and finally figure out it is the ole Caprice with a diesel that they hear.

Can an olds 350 diesel fit into a 1977 Chev Van? If so, does anyone have one for sale? Running or not. I make biodiesel and I want to convert my old van to run it.

Short answer is yes. There is plenty of room.

That being said, there will be some modifications to make it work. Try to aquire a complete engine, with all accessories included. This will give you the brackets you need to mount the power steering, alternator and A/C compressor. Make sure the engine has all it's pulleys too. They are a bit different from the Chevy to the Olds.

Olds and Chevy used a few different types of motor mounts too. You'll need the Olds engine mount and either the Olds or Chevy frame brackets. There were a few different variations over the years, but some time spent in a junkyard looking at various Olds powered and Chevy powered stuff should yield parts to do the job. Olds gas and diesel engines shared mounts, brackets and mounting and will completely interchange, so parts from a Olds gas powered vehicle will work.

Transmission bellhousing patterns are different between the two. A 77 Chevy van with an auto would have used the turbo hydramatic (TH)350 transmission. Some of them have both the Chevy pattern and the (Buick/Olds/Pontiac/Cadillac) patterns. There are also many of the BOPC versions still out there. An adapter can also be used and are available in the aftermarket for less than $100.

The easiest way to put a diesel in your van from an availability and interchangeability standpoint is to use the 6.2/6.5 Chevy/GM diesel. It is completely interchangeable with the V8 Chevy gas engine and if your van has a 6 cylinder, only the mounts may have to be changed. Those engines are far more common, more powerful and more reliable. If you buy one of those, try to get it complete as well.