THAT would be the ideal solution for sure.

 

How much are you willing to pay to make this happen? What is your budget for this upcoming event?

 

I'm VERY familiar with the 6.2/6.5 GM diesel. Designed by Detroit Diesel for General Motors as a light truck economy engine. The 6.2 was a pure mechanical injection diesel (6.5 used an electronically controlled pump PMD) Although hardly a power house it wasn't a "dog". The engines are plentiful and cheap compared to many diesels. It is the engine that has powered every military HMMWV made (AM General now owns the patterns and makes a slightly HD version themselves).

The addition of a turbo should be included for best all around performance (diesels love turbos). Nothing crazy, even a free-floating (no waste gate) of 10 PSI works wonders for power and economy. The weight of a 6.2 is comparable to a Chevy big block. Pennisular Diesel used to be THE 6.2/6.5 performance house during their heyday.

The Duramax, Powerstroke, and Cummins are medium truck engines and can be very powerful, but the extreme weight and other requirements do NOT make them a logical swap in a Corvette IMHO.

Here was my old Jimmy K5 (one ton axles 4.56 gears, TH700R4, 38x15 tires). I ran a 6.2, with 6.5 turbo prechambers, tweaked injection pump, PTC glowplugs, and an ATS turbo. The power felt like a good 350 gas engine and still got 20 MPG!

 

But that's not to great when you figure my 10,000 lb f250 crewcab 4wd makes 600hp and gets 20 to 22 mpg. So no thanks on the antique gm diesel attempts.

Plus like I mentioned if mpg is what he wants 50mpg from the 4bt cummins is the hands down way to go.

 

Packaging wise, you're far better off with a duramax.
The duramax is also metric hell loads lighter (by several hundred pounds) than the Cummins. A Duramax weighs comparable to a big block chevy.

A cummins weight is comparable to a mazda miata. Duramax is also about the size of a BBC in exterior dimensions.

Also the old 6.2 and 6.5 GM diesels can be made to work, and respond well to mods. My dad had a 6.2 van..the service interval for a full rebuild was something like 150,000..I know for a fact that engine had 250,000 when he got it..and he put another 150,000 on it easy.

That all aside...these suckers are going to alter the weight balance of the car, pretty heavily. I'm not even remotely sure what you could honestly do to offset the weight vs the SBC.

 

That, right there, tells us so much.

Unless you have a close friend with mechanical experience who is willing to help, you might be the wrong person to attempt to undertake a project like this.

20 mpg? In other words, just about what a good 350 gas engine gets...only you're paying $3 a gallon for diesel instead of $2 a gallon for gasoline? Same power, worse fuel costs; everyone should want this.

 

If he had a gas engine he'd be getting almost half of that...down hill.
Look at his gears, then there's the tire size, then throw in the poor aero of the vehicle (which yes indeed matters ALOT) then overall weight.

A duramax powered Gen 3 F body, can nail 35 mpg all day long, and make 500 horses, for example.

 

Maybe a DuraMax could "fit" in a C4 engine compartment and you might even get it to run once all the accesories and wiring are figured out and installed. But one thing that has not been mentioned is the rest of the drivetrain. A diesel would have to either bolt up to a Corvette 700R4 or some other auto trans where the tailshaft housing could be modified to attach the C-beam to it.

Don't forget that a C4 with a factory auto trans came with the weaker D36 differential. Depending on the diesel that finally got installed, it may be that the D44 from a standard-trans C4 may not be up to the power output.

While this project sounds interesting, I'll bet that it will be nearly impossible to do. Too many unknowns like weight, suspension issues including weight distribution, drivetrain strength and design, wiring and other components like fuel lines, pumps, filters, and even room under the car.

As far as operating costs, around here there is about a 45 to 60 cent difference in the cost of 92 octane gas and low-sulphur #2 diesel. Whether or not that's enough to make a difference (or even care), the cost of the conversion and the time it could take to do it would be the deciding factor.

 

I'm sorry, and I know we're not suppose to discourage creative thinking, but has anyone addressed the engineering, mechanics, and logistics of such a swap? seems to me, some people think this is some sort of plug and play thing. all I'm hearing is what is the best diesel powerplant out there. aside from that, nobody's addressed the increased load on the front suspension, upsetting the weight and balance, and the steering and handling characteristics of the car. an 85 corvette is not a K5 jimmy! the whole thing sounds like a half baked idea. the next thing, we'll be adding in 4X4 and monster truck tires. a saturday night cruiser/show car - yeah, right!!! IMO, we shouldn't even be discussing a concept abortion like this on a C4 tech/performance forum. this thing may or may not ever get off the ground. if it does, I'd be willing to bet that it will end up as some crash and burn project, never getting finished. as I said before, the OP's car, and his money - hope he has fun! BTW, I think i'll register the web site, www-dot-dumbphuckin'idea-dot-com - - now there's a real brain fart! ( flame suit is on....)

 

The first step is picking the power plant and the power levels you want to achieve. Then you build the drivetrain accordingly. And the weight distribution, has already been mentioned.

http://www.dragzine.com/news/video-a...ered-chevelle/

http://www.dieselplace.com/forum/63-...diesel-28.html Diesel powered Gen 4 F body...who's engine bay is much tighter than a C4's
People have done it.


Actually in the Chevelle community it's kind of fairly well known at that. (not like it's going to ruin the handling of a chevelle..let's be honest)

 

Wow such hate. The old CF has gone to hell hasn't it. Some people get it some don't. The OP asked for technical input. I gave him what I believe would be his best option. Yes there are hurdles still but with a 6.2/6.5 they are surmountable without a mountain money or expertise.

The Duramax is the lighter of the big three (Powersmoke, Cummon, Dura) but still outweighs the 6.2 by almost a hundred pounds. It does have superior performance, but at a price and complexity. 6.2 was mated to a 700R in many applications, so there's a big piece of the puzzle solved right there. Yes it weighs more than a SBC, more in the order of a Big Block; heaven forbid someone swap in a BBC in a C4 As far as a 4Bt goes I honestly don't think you could fit one under the hood unless you included the hood scoop from hell.
http://www.dieselhub.com/tech/engine-dimensions.html

The new generation of diesels are nice until you have to repair one. The old indirect injection isn't bad if built right, lasts forever, and can be repaired for hundreds (thousands) less than the newer DI common rail systems.

If I had an old un-wanted '84 vette sitting in my backyard I'd be swapping in a 6.5 as we speak. Just to **** off the naysayers

 

 

I used to drive a diesel Blazer in my Army Reserve unit. That thing had some serious grunt. Later on during Desert Storm I got to drive a Hummer with the same engine. What a hoot in the sand/dirt!
Lots of luck with the project and more power to you if you can pull this off!
Ever think about going the other direction? A Forum member here used to drive a C4 with a turbo Grand National V6 engine. Seems like it would dip into the 9s in the quarter mile.
Found a clip of one here here:

 

If you can get a K5 running 38s to get 20 mpg running a 350, I'd be inclined to buy it from you. I've had several square body blazers and you aren't getting anywhere close to that, even in a stock one. Not a big diesel fan but the 6.2/6.5, were very good in light duty trucks. They weren't without their issues, but they were great for their time. Still run in Hummvees.

 

Kind of sad to see the lack of innovative spirit or even words of encouragement on here. I am supposing that most of you don't realize that hot rod innovation is what brought us the high performance cars of today. Even the early Corvette concept was an engineered spin off of hot rodders shoeing a bigger American mill in a sports car.

Live a little outside of your confines; it's not going to kill you.

 

do it just because they tell you that you cannot, thats how I role

 

I hate the 'why' comments, too, but they're on most forums.

Not being a diesel guy, a friend who is, suggested an Isuzu 4 with propane injection for TONS of torque.

You should see the notes I got when I playfully proposed putting a Nash flathead 6 in a Vette! I doubt many knew that one powered an Indy car for a couple years.

See, I have a Vette powered F100, a Rustang HO 5.0L in a Nash, so..... I toyed with using a turbo-jetski engine in the Nash!

 

Earliere I had a Dodge Ram 5.9 cummins, great engine but for a vette maybe a smallere lighter engine would be better. If you lived in Europe I would suggest something like a BMW 4.0-4.4 V8 diesel from a 740d...

http://en.m.wikipedia.org/wiki/BMW_M67

Weighs 423 lb and have 329 hp/552 lb ft in the most powerfull edition. But the electronics would probably be "interesting" :-)

 

A 6.5 in a C3 appears to have been done:
http://www.thedieselpage.com/readers/vet.htm

 

Do a small turbo diesel out of VW TDI, interesting/different/small enough to fit/lighter weight, etc etc. Getting an adapter to mount it to the transmission would be the only tricky part.