"Oldsmobile Diesel" Conversion to gas

[fredocrox]

I've just taken over my grandfather's '79 Chevy SB with the 350 "Olds diesel" engine. It ran when it was parked 20 years ago, but hard to guess what all would need to be done now. I'm considering whether to work on the stock motor or just find a 350 / 403 / 455 gas motor and move on, hopefully sourced from an Oldsmobile.
Welcome thoughts on the question, as well as sourcing ideas for the "Replace" option.
Thanks in advance.

 

[Sad Sack]

Reading the Wikipedia about that engine gave me the heebie jeebies. I'd go with an Olds gas engine.

Oldsmobile Diesel engine - Wikipedia

en.wikipedia.org

Or throw a Chevy in it with a trans adapter if tranny is an Olds.

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[Ricko1966]

My first choice would be a 455 Olds,I have no idea where to find one anymore,used to be you'd just find a rusted out Delta etc and pull the engine.

 

[Turbo4whl]

350 "Olds diesel" engine

Best use for that engine is a boat anchor in the lake.

 

[Sad Sack]

My first choice would be a 455 Olds,I have no idea where to find one anymore,used to be you'd just find a rusted out Delta etc and pull the engine.

@Ricko1966 I assume these trucks used Olds transmissions, yay or nay?

 

[Ricko1966]

@Ricko1966 I assume these trucks used Olds transmissions, yay or nay?

BOP transmissions,he can bolt a Buick Olds or Pontiac engine to that transmissions. I'd be tempted to use a 455 Buick,but you are on your own there,not a job for a novice. The Olds is a simple bolt in deal,and the 455 Olds has tons of torque.

 

[Sad Sack]

BOP transmissions,he can bolt a Buick Olds or Pontiac engine to that transmissions. I'd be tempted to use a 455 Buick,but you are on your own there,not a job for a novice. The Olds is a simple bolt in deal,and the 455 Olds has tons of torque.

That's what I thought. I had a 1980 T/A with a 301 "TURDO" and did the Chevy /adapter - worked great

 

[Ricko1966]

Best use for that engine is a boat anchor in the lake.

Or sell it to someone wanting to build a high HP Olds Small block. The diesel block is more stout than the gas block. But no one is building Hp Olds Small Blocks

 

[backwoodsman]

I did a lot of research on the 350 diesel before buying one. Its reputation is a lot worse than the reality. Its biggest problem is caused by GM's decision not to use a water separator, because they didn't want drivers to have to think about the fact that it's a diesel any more than necessary. Unfortunately that lets bits of water get into the engine occasionally. Water expands a lot when it turns to steam, creating very high cylinder pressures. If that happens at full throttle, it can result in stretched head bolts and blown head gaskets. So if you get an engine that hasn't happened to, and put a water separator on it, you won't have that problem. And without that problem, it's actually a pretty good engine.

My 350 diesel is in an '81 Cadillac Sedan Deville. I bought it because it's a diesel. It's not going to win any drag races, but it'll cruise just fine at 65, and it gets 30 MPG on the highway even with the overdrive not working, and 20-22 MPG in town. Hard to argue with that in a 5000 lb. car that rides like you're sitting in your living room.

So I'm going to disagree with most here, and say keep that 350 diesel. You have a classic truck there, there never were very many with the 350 diesel, there are a whole lot less of them now, and it would be a real pity to lose one. If you really want one with a gas engine, maybe consider selling it and buying a gas truck.

 

[edgephoto]

I am with @backwoodsman. Add a good water separator and drive it. Back in those days diesel was real dirty too. It was dark colored and cloudy. Now diesel is much cleaner. No worse than the 6.2

 

[Ricko1966]

It hasn't run in 20 years,I seriously doubt someone's going to change fluids add a water separator and drive this. My guess, if the engine still turns over it's going to need injectors and an injector pump minimum and I'd guess a lot more. Maybe I'm a pessimist but I don't see reviving g a 5.7 diesel for less than the cost of a gas engine swap.

 

[ali_c20]

If everything is original I would fix the diesel and run it. Bring grandpas truck back on the road as it was when he owned it.
Having an all original truck is great imo.
Add a good water separator like mentioned before.

 

[AuroraGirl]

if it helps to hear from GM what their attitude was:

We continue to hear about diesel cylinder heads being replaced because of cracks between the intake and exhaust valve seats. Cracks in the seat area are normal for both the 5.7L and 4.3L diesel as well as some other diesel engines produced by other manufacturers. Many cylinder heads that have been returned have been examined and the cracks are superficial. The coolant is approximately five-eights of an inch away from the crack and therefore will not result in a loss of coolant or compression. Refer to Dealer Technical Bulletin 81-T-40 for additional information.

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Two (2) new cylinder heads have been released for service for the GM Goodwrench 350 diesel engine. The new cylinder heads, P/N 22523637 and 22523638, have different dowel pin locations than cylinder heads previously released. Previously released cylinder heads may be used on the GM Good- wrench diesel engine by changing the dowel pin locations in the block to agree with the holes in the head. DO NOT install heads without the dowel pins.

there is a lot more TSBs from GM regarding them, some about lifter design change, fuel line heater kits, fuel shutoff solenoid, and proper gasketing techniques for the water pump and etc. They CAN Be made proper, but as they came out.... they were problems

 

[TotalyHucked]

I'd also agree with trying to get it running as-is and go from there. Junkyard Digs on YouTube has revived several Olds diesels with pretty decent success. If it's still a healthy engine, like others have said, add a water separator and roll on. You'd have a cool, unique pickup that'll get fantastic mileage even if it's slow.

If the motor turns out to be junk, no harm no foul at that point. I'd try to find a big Delta-88 or something and pluck the 455 out of it

 

[Turbo4whl]

@backwoodsman

Well as a collector item you are right. Not many still have the 350 oil burner, they have been swapped out.

We had them back in the day in the fleet. Nothing but trouble. Carol posted real info from GM, they were covering their a$$. Cold start, make sure the block heater is plugged in and both batteries are up to the task. Have you ever unbolted a head then removed it in two pieces?

Make sure you have a good place to take the injection pump to, for overhaul. Dan I see you have the 6.2 oil burner in your truck. Much better engine.