Diesel engine success in our G cars..

[KrisW]

On a swapping note, the GM 6.5 turbo diesel found in light and medium duty trucks will bolt to SBC mounts and has the same transmission flange. It may be a viable alternative to the typical gas swaps into a dead diesel G or B body car. The only drawback I can think of is weight as diesels weigh more than gas engines do. This engine also has a reputation for bad injector pumps, and I have heard that GM did sort of a silent recall on them. The new pumps are supposed to be better. A friend of mine has a Chevy 1 ton crew cab with this engine and GM did the repairs for free because of this.

I have worked on these alot as well. They only need head studs, a good injector pump, and an electric lift pump to run really well and get good mileage.

The injector pump is the same unit used on everything from old CASE farm tractors to new John Deere engines of today. It is configured for 8 cylinders but the internals are the same. The rebuild kit is less than 50 bucks.

 

[Jim Rockford]

yea but the 6.5's get horride mileage compaird to most other engines
I think i seen 19mpg thrown around somewhere

 

[KrisW]

19 miles per gallon is exceptional in the exact same truck that gets 13 with a 350 or 10(or even less) with a 454. All of these were usually 3.73 or 4.10 geared.

It really is comparing apples and oranges no matter what you compare the 6.5 turbo to anything else. I have no reason to believe that you would get anything less than 25 mpg in a monte carlo with this engine and overdrive. A 3/4 ton or 1 ton truck is a different animal.

And compared to the dodge 5.9L that it used to compete against, again it is very different other than using the same fuel.

 

[85 Cutlass Brougham]

My friend's 1 ton gets 19.5 city on summer diesel, despite weighing the better part of 3-4 tons. That's pretty good for a heavy, 4x4 truck if you ask me. I only get 20-24 in my 4 cylinder 3200lb Nissan Frontier.

While I do not want to do this to my car, I would be interested to see someone try it. Then again, If I could find a broken diesel G body and a wrecked 6.5 turbo truck for cheap...

 

[Regal_Nut_84]

Since you guys are talking about diesels... (and a couple of you seem to be enjoying success with them) I have a few questions. BTW, HI, I'm the new guy on the block! LOL

With gas possibly hitting $5.00 a gallon this summer (dumb-@$$ speculators), I am eyeing the 6.2L diesel in a derelict motorhome I own with dubious intentions.... it's getting nervous.... MUAHAHAHAHAHAH!!!

What little I have read about G-bodies and diesels is limited to the 4.3L V6 and 5.7L V8 Oldsmobile diesels being available in the Buick and Olds G-cars through 1985, and were coupled to either 200-C 3 speed or 200-4R 4-speed automatics. The Oldsmodiesel is a strange beast. Some people love it, some people hate it. From my reading, I have to agree that most people are simply uninformed about these engines, and that their problems are not difficult to overcome. It seems to me that most of the problem was uninformed owners driving and maintaining them like a gasoline engine, which no diesel will tolerate for very long. They require different oils and different service intervals, and I believe most people simply ignored this. I have heard of Oldsmodiesels achieving 30 mpg highway, in LARGE cars like a Delta 88, which is awesome!

That said... This is what I have, a complete 82 Chevy motorhome with a rotted roof and a 6.2L diesel. Ran and drove great with no smoke last time it was fired. My car is an 84 Regal coupe with a factory 4.1L 4-bbl Buick V-6 (rare?) 200-4R 4-speed auto and what I believe are 3.42 or 3.73 gears.

It runs fine... I plan a GNX clone, but I want to DRIVE this car, even as fuel prices surge. Yes, a diesel rattling happily away under the hood will be a dead giveaway it's not real. Don't care, want to drive it. Search YouTube for a Duramax Grand National.... NOT KIDDING! I've also read that turning up the fuel on a 6.2 with upgraded injectors and a turbo will make it run with a stock 350. Not looking to build a speed demon, but I don't like cars that say "What?" and laugh when I open the throttle.

My car came with a 200-4R 4-speed automatic, which if I've read right, has both bolt patterns and will bolt to the 6.2L. I know that later 3/4 ton trucks used the 700-R4 with later models of the 6.2 and 6.5. I have also read a small bit of others who have used a 200-4R with a 6.2. Apparently, it can be done, but my questions are...

(1) Are factory brackets for such accessories as TV cable/cruise control possibly already in place on the 6.2?
(2) If not, will adapting them be difficult?
(3) I have read of 2.5-ton pickups getting 33 mpg with this combo. What can I expect with it in a 1.5-ton sedan?
(4) Will the torque of the diesel require modifying the 200-4R transmission?
(5) Will the stock coil springs my V-6 car came with be sufficient?
(6) Should any other suspension components be reworked?
(7) What, if any, cooling system upgrades should I make?

Flame away......

 

[custom442]

welcome to the forum! to start I don't have any personal experience with olds diesels. But for some of your questions, the tv cable brackets on your old 4.1 should be able to bolt somewhere around the 6.2 throttle body with a little modification. The early 6.2's are very rugged and I like the idea you're going with.

The problem with this idea is the cost issue. To save gas or pay less at the pump, its obviously a terrible idea.

The v6 2004r will not last long at all unless babying the new engine at all times. The stock 700r4s behind those, (or nv4500 but thats even more $$ and time and work) with rebuild should last well. I say use the trans from the motor home and rebuild it (what trans is in there?) The nv4500s are just as rugged as the 6.2. The rear will be trash, might as well throw it out now.

Think also about suspension and mounting the engine, I'm sure mounting won't be a problem since sbc to duramax swaps are very common and your car has provisions for sbc engine mounts. Stiffer front springs and some suspension mods will be needed, the 6.2 is a LOT heavier than whats in the car now. You won't get 33 mpg and should be happy with 20mpg. 33mpg is bullshit btw. I have some friends with duramaxes and they're incredibly efficient but not anywhere near 30mpg. 25 is realistic and about the most that can be sucked out of the newer duramax with high rear gear and a very lightweight truck.


If its gas mileage or power, there's better ways to go, spending that much $$ and effort to get a car that does 18mpg with this idea isn't worth it. A well built 4cyl turbo would make as much power and save $$ without making so much torque to eat a house and adding extreme excess weight

 

[MR442]

I ran V6 diesel for year as a beater car . Could beat about any MPG in a gas car of same size today big time . Also Had V8 in the 98's . Hey 10 MPG more in a car is a big thing . 403 got 20 PLus the same in fuel form almost 30 mpg on trips

Loved the V6 by the way . Wish got more than 200000 miles out of it tho.

The newer diesels r so restricted . Used to get 20 plus all time now luck to break it in a truck .

Its reliable but not hot rod . I go for reliable .

I got a V8 diesel cutlass in the weeds who knows, Veggie oil here I come .

 

[megaladon6]

Somethings to keep in mind about diesels
1) they drive like dogs more because of the gearing than the engine. MUCH more
2) the newer ones dont have the greatest MPG, due to emissions. All of that is in the computer programming---its easily changed. The only other limits are injector nozzle and turbo size.
3) diesles dont care about weight

 

[upandaway84]

Anybody have an idea as to which Gbodies had the RWD V6 diesels in them?

 

[Blake442]

The ones that were ordered with them...

The diesel V6 was only available in '83-'84 I believe, and I think by '85 they were both gone.