I was talking to my Diesel guy last night and he told me he has a 6.2 Diesel for me to play with from a Hummer, he said its the same block as a SBC just HD and to use it all Id have to do is swap the heads & intake. Is this true could it be used in a gas application, I know anything is possible and i have converted an older olds engine from diesel to gas with just an induction swap but I havent seen anything similar enough in the very few diesels I have played with to even consider the possibility in a chevy application. .

 

The biggest difference in a diesel I know of is they are not "electronic" in that they don't use spark plugs, instead they use a massive stroke to generate very high compression ratios and ignite the fuel under the universal gas laws dp/dt is proportional to dT which is change in pressure over change in time is proportional to change in temprature. In a diesal the change in pressure is enourmous (well pretty high lol) and the time, well you can figure that out by RPM but for example, at 650 RPM idle, you figure in one rpm each piston will go through 2 cycles, for example intake/compression. So 650RPM = 10.83 RPS makes for .09 Seconds per revolution. We are interested only in one of the cycles, compression, not one revolution, so we divide that in half, and get 0.045 seconds. Large change in pressure/small change in time=high temp=diesal fuel burning.

Now all that said, you ar saying its a 6.2L diesal. It sounds feasible that going from 5.7 to 6.2 and doing a few other CR increase things, could make for the kind of compression needed for a diesal. Best bet there would be to get measurements, see if a 350 or even a 383 crank will fit, check the bore of the motor, etc. Let us know what you find out.....my next block....after the LT1 could theoretically be a hummer diesal block lol

 

That doesn't answer the question at all, i would also like to know just to know. LOL

 

I very seriously doubt that it's the same. It just so happens that a 383 is 6.2L Now I'm fairly sure that 6.2 diesel has a smaller bore than stroke, which means that the stroke of the diesel is much bigger than the 383, which means the cam is going to have to be higher in the block and the crank case is going to have to be wider to accomodate that huge crank. The deck of the block is also going to have to be taller so the piston doesn't fall out on its way down and the pin isn't pushed up into the compression ring.

I'd be willing to wager that 6.2L diesel, which is the biggest POS of cast iron that ever rolled out of Detroit, has as much to do with a SBC as the hair on my butt!

 

I don't know about the current 6.2 diesel... but back in the early 80s, they first had a 5.7 diesel in cars, which was made on an Olds 350 block platform..... totally inadequate. And the Olds block is a great deal les unsuited than a SBC to that particular modification. Then in about 82 or so they came out with a 6.2 diesel that was almost a real diesel motor from the ground up, and it's completely different from a Chevy (or any other gasoline motor).

Long story short, I seriously doubt it resembles a SBC at all.

 

Lets put it this way. There's nothing on a SBC engine that will fit on the 6.2 diesel.

The 6.2 is a piece of junk. It's hard to find one that doesn't have cracked heads. The 6.5 isn't much better.

 

Kinda unrelated, but the best thing Chevy did was outsource their diesel program to a reputable manufactuer. The 6.2 or 6.5 were about the most underpower POS on the market. Alot of farmer (round here anyway) usually either offed the trucks or pulled the motor and fitted with a big block. The blocks themselves should bear no ressemblance at all to a SBC, except maybe motor mount location.

 

Well, He's going to bring it in tommorow so we'll see. Like I said I dont know squat about these engines but there was an older 80 somthing sitting in the corner of the shop before and it dident resemble a SBC at all.

 

this kind of question to me goes back to the boring a 305 to a 350. if it were really that easy, there would be a ton of 6.2's converted over, especially with the stronger parts they used. small block and 6.2, not a match.