which block to use!

[brian wafer]

hi just got a 6.2 out off 1992 k2500, truck had 110,000miles the block is a 2 piece crank seal with casting number 680 or 630 hard to tell if 8 or 3. more likely 680. motor is very clean looks almost like a rebuilt. how many series off block were made, is it worth keeping ! didn,t 1992 come with 599 block if so motor must off been replaced, can,t seem too find a good 599. thanks for any comments! ps it will have a turbo charger!

[Robyn]

If the engine you have is sound and there are no cracks in the bottom end I would say use it.

The 599 6.2's came along in that time frame 91-93 and there is no real way to tell exactly when they started using it.
Take the date code off the block and you can see when it was made.

Depending on where the truck was made and the supply of engines that was available you could have gotten either 1 or 2 piece RMS.

There is no real advantage to the one piece. If you use the neoprene seal instead of the rope one all is well.

Just coat the ends of the seal (where the butt) with something like "High Tack" they are fine.

Some folks will offset the seal so it does not part right at the split line but I usually just goo the ends and butt them at the part.
Never had one leak.

If the CDR system is working properly they will be as good as the one piece.

Robyn

[More Power]

According to PROSIS - AERA Technical Services, the block casting numbers 10149599 & 14109599 were produced in the 1992-93 model years, and were the first to offer a one-piece rear main seal.

The block casting number 14022660 was produced in the 1991 model year. I couldn't find a 630 or 680 casting number in the list....

The advantage of the one-piece rear main seal is that you don't need to drop the oil pan, oil pump, and rear main cap to replace the seal. The GM service manuals indicate that the ends of two-piece lip seal should be offset from the main cap parting lines, to help with sealing. It's easy to install them in an offset position - once you get everything apart. ;)

Jim

[4xjunkie]

The block casting number 14022660 was produced in the 1991 model year.
Jim


Are you sure about that??

I just picked up a 6.2 with the 14022660 number but below number is cast 10-29-81. I don't know it is just something I noticed.

[diaric]

660 was the casting from 82-91 until the one piece seal casting in 92-93 that was in anticipation of the 6.5

[convert2diesel]

Reviveing this thread as I was just checking the engine that came out of the 89 GMC 6.2 and it is also a "680" block. Numbers are clearly marked. Could this be a block specifically made for the military? The rest of the truck is military spec but re-routed during production to the civi side. Had a hell of a time crossing the parts until we discovered it's military heritage. If so wonder if there is any differences?

Bill

[Robyn]

As far as the block goes there wont be any issues with parts fitting.

The accessories and other bolt on stuff will be different on some military engines but the basic block will accept all the standard civi goodies that bolt to any 6.2/6.5

Hope this helps

Robyn

[convert2diesel]

Yes, all the bits should be interchangeable. My question revolves around structural integrity. Also have a 599 in pieces that also checks out that I can use for my next project but the 680 has been such a good engine so far, I'm leaning toward re-building it. Will have to be bored out and new pistons, etc. as it has over 500K on it, but just wondering if it would be worth the effort. It's rare to find an engine that literally wore out the rest of the truck and is still running with 400 PSI compression (after 12 puffs).

Just wondering is all.

Bill

[Robyn]

Life as seen from Missy Robyn's Garage :)

My rule is simple, a high mile block that is structurally sound is a great foundation.

A well seasoned block that is crack free or that has some small main web cracks that can be inserted is the best piece to use.

The crack free high mile block is likely going to remain so unless a crank breaks or a dampener fails and is allowed to run that way.

The original RED blocks were said to be the best iron in the series BUTTTTTTTTTT I have seen these with cracks too.

The early 599 6.2 blocks are a fine piece to build on.
I had a 599 6.2 that was made in 94 (Military)


Have fun

Robyn