I have 2 GM diesels, a 93 K3500 with a crapped-out 6.5 (a rod knock and a blown head gasket), and an 85 Suburban 3/4 ton with what I thought was a 6.2. I just bought a 6.2/700R4/NP208 from a strong running blazer (for $375) that I was going to use to replace the 6.5 in my 93. I was looking over both engines to come up with a game plan for the swap. I noticed that the 6.2 off the Blazer didn't have the oil port for the turbo supply. No problem, I thought, I'll simply have to get a longer hose made at EVCO. Then, out of curiosity, I took a look at the front of my Suburban's "6.2" and lo and behold, it does have the oil port for a turbo.

Now, I have turned up the IP on my "6.2" in my Sub twice and I still never get any black smoke on acceleration or hills. Also, I bought this motor out of a junked 1.5 ton tow truck, so I dont think that it would be too much of a stretch that it could be a 6.5.

How can I verify definitively what engine I have in my Sub?

If it is a 6.5, I would rather take that engine and install it into my 93, with the turbo, and throw the 6.2/700R4/208 into the Sub as a single unit.

.

How can I verify definitively what engine I have in my Sub?



Post the engine casting numbers, and date code from the rear of the engine, behind the heads. Cast number on driver side, date code on pass. side. Someone will be able to decipher them.

Edit:IIRC, Cast # ending in 660 is a 6.2, 599 could be either late 6.2 or early 6.5, anything else should be a 6.5. Someone will correct me if I am wrong..

I THINK IT IS A 6.5!! I just compared the injectors on the Blazer 6.2 and my Suburban's engine. The blazer's injectors are about 3/4" longer! Also, there is a casting on the front of the engine right under the passenger side head. On the blazer's 6.2 it says "6.2 LD". On my 93's 6.5 AND my Suburbans 6.5(?) it says "GM LD"!

WHOOOOOOHOOOO! I HAVE A 6.5 FOR SUPER CHEAP FOR MY 93!

IIRC, 599 block didnt say 6.2 or 6.5 up front, just the GM LD? I'd look at the casting number at the rear. Sounds like a 599 block.
Edit, I'm willing to bet the 6.5 in your '93 is a 599 block also. Remember, 599 block can go either way, only way to be sure, I'm told is to pop the head, and measure the bore.

If it was a 6.5L it would be stalling. :)

Post the engine casting numbers, and date code from the rear of the engine, behind the heads.

What's the best way to do that? I just spent 15 rolling around under the suburban with my wife's make-up mirror and a flashlight. I still wasn't able to read the code.

(Dont tell my sweetheart that I had her mirror crammed unserimoniously into the oily crevises of my suburban!)

How did your makeup come out? Uhh. never mind I don't want to know.

If it was a 6.5L it would be stalling. :)
Even if it was naturally aspirated originally? Remember, even though it has a 6.2 IP on it, it has been turned up twice.

OK, I just spent another 15 minutes with the makeup mirror. I think the cast number is 10148599.

So, do the 599 6.2's have the port on the front for the turbo oiler?

And, assuming that it is a 6.2, which one would be a better candidate for turboing in my 93?

One more question: Do the 599 6.2s have the short injectors like a 6.5?

And, assuming that it is a 6.2, which one would be a better candidate for turboing in my 93?

I think it is a widely accepted fact that the late 6.2 599 block was generally superior to the earlier 660's so would be your better candidate for turbo use, of course that depends on other factors like wear, checking for cracked webs, etc. The 599 was also the only 6.2 that had a one piece rear main seal, and had more beef(iron) in the block around the cylinders, because the same casting was being used to bore for the larger 6.5.
If it is indeed a 6.2 when you measure the bore, it could easily be bored to 6.5 specs.
I think the injector issue can be misleading, as long and short injectors are generally interchangeable. I can speculate, that by the time the 599 block was being used, (production of 6.2 and 6.5 going on side by side) the injectors, and injector lines, and perhaps other parts, like the oil port were probably being used on both. This is where the date code could give some clues also.
Was the sticker in the glovebox of the donor Blazer? That would give you the engine code, and may be the best clue as to it's true displacement.(short of measuring the bore)

Gm used "short" injectors in vans to begin with back in 88 I think. They did it for clearance problems. Then a few years later they put "short" injectors in all applications.

Ahh. I see.

One piece of info that I forgot to mention, I ran with an IP from a NA6.5 on my Suburban for a few months last year with absolutely no smoke. The power was nice! I killed that IP with a slug of cold veggie oil when I ran out of diesel on my warmup. That is why I am back to a 6.2 IP on it.

Not producing smoke with a 6.5 IP would be indicitive that it was, indeed a 6.5 would it not? (Not definitive, but indicitave)

[Not producing smoke with a 6.5 IP would be indicitive that it was, indeed a 6.5 would it not? (Not definitive, but indicitave)[/quote]

I am not sure why that would indicate it would be a 6.5.

Like somebody else said, measure the bore

One other thing that might be of help is the sound, my 599 6.2 has the 6.2 precups and runs just like the older 6.2

I always thought they sound different when running, even the N/A 6.5 had a different sound than the 6.2

(Not definitive, but indicitave)

The 599 block is "indicative" that it MAY BE a 6.5......
Measuring the bore is the ONLY WAY to be "definitive";):)

My understanding is that the 6.2 with the one piece main seal is much stronger, and that the amount of displacement difference is negligible, considering the advantages of more iron, stronger block,etc. I would NOT bore it out, but would simply turbo the 6.2. What do you guys think?

Rob ;)

OK, folks. I took Saturday and pulled the 599 6.2(?)/TH400/208 out of the burban and dropped in the 660 6.2/700R4/208. When I got the 599 engine out, I was able to read the casting code and date code clearly. This is what I found:

Cast #: 10149599
Date code: CO94

Can anyone help me out with the date code? As I understand, it must have been cast in 94. Did they even make any 6.2s after 93?

A motor that old coming from a tow truck may have been put together using a multitude of parts,.measuring the bore is the exact way to know,.
nick

A motor that old coming from a tow truck may have been put together using a multitude of parts,.measuring the bore is the exact way to know,.
nick
Yeah, that's not going to happen. I'm not going to open up a perfectly healthy engine just to measure the bore, just to satisfy my curiosity. That is why I posted the casting number and date number, so that if someone out there had any useful, pertinent info, regarding those numbers, they could post it.