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decoding help please on a 6.2

T

toolinarnd

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Hi everyone I just found this site, and am hoping some one can help, we purchased a 6.2 military surplus engine and are not sure about the year the casting# are 125506 and what we believe is the date code is C422L any help with this would be greatly appreciated.
Thanks in advance Shawn
 
Welcome to the Forum! :welcome2:

Do you have a year for the motor? Please take a few minutes to fill out your signature with more descriptive information on your specific vehicle or engine as it helps fellow members diagnose the issues that you may have.
 
Are you sure the first digit is a "c" and not a "0"?

04 -22 - L

Apr - 22 - 2004

That would be how the GEP optimizer blocks are date coded. The casting date is on the RH rear corner of the block just below the head.

The "506" is consistent with an Optimizer.

The dead give away is the Navistar "endless roads" logo cast in the lifter valley floor. It looks like two triangles back to back, you can see it here:

69655d1217253922-gep-6500-optimizer-reply-factory-imgp2391.jpg


GEP took over 6.5 production in 2000/2001 for the H1 with a redesigned assembly (Optimizer 6500) and started a new numbering code:

H=2001
J=2002
K=2003
L=2004 and on in the series

The first two digits are month
The second digits are the day
The last digit is the year

GEP doesn't have a foundry, so they contracted the block and head castings out to Navistar (they have/had two very good foundries) who slipped their own logo on the parts. Kind of like Ford slipping a scripted "F" on all the Jeeps they made in WWII....
 
great white said:
Date casting code on a GEP Optimizer should look like so:

IMG_0368_2.JPG


That's 03-17-L

Mar 17 2004

The older GM cast block codes look like so:

blockdatecode.jpg
Click to expand...
thank you for all the help you are correct it was 04 22 L.

Does anyone Know if this has the oil sprayers that lubricate the cylinder walls straight from the oil cooler?

Thanks again for the help
 
ak diesel driver said:
all the new blocks are at least machined for oil squirters AFAIK
Click to expand...

In this military engine, it is machined with the oil squirters. Only cyl 7 and 8 are actually squirting as it sits now. You will need different crank bearings to turn on the squirt on the other cylinders. I might be wrong but I think this is correct.

Can someone confirm this? It's been a couple of years since I rebuilt my military GEP and things are foggy.
 
Correct, the 6.2 mil should have the low volume oil pump also. Pick up a high volume oil pump and new bearings with the holes for the squirters and enjoy a happy longer engine life. Don't worry about brand of oil pump, as Melling is the only mfr. they just rebrand for all the other companies.
 
Ahh yes! The high volume oil pump is a critical part of this equation. I would add that the high volume oil pump won't fit the humvee oil pan without some modification, but that's okay because I don't think the humvee pan will work in your civi truck anyway.

What is this engine going in to anyway?

I went down this road a couple of years ago. Actually I am still on that road. I bought a surplus GEP and rebuilt it. It is still sitting in the crate at the moment but hope to drop it in to a '95 C2500 before the end of the month.

We had a great time firing the engine in the crate. You got the crate, right?
 
I'm a bit foggy about it, but something was not working out somewhere between the different oil pans and the different oil pumps. Might have been trying to use humvee oil pump and a civi pan. Can't remember the deal. I wound up with a pump and pan from a '98 C2500 and everything was fine in the end.
 
Ok, because only low volume and high volume oil pumps that I know of. Nothing special about hmmwv/hummer oil pumps. I know pan from hummer 6.5 n/a or Td is same pan from savana van w/ 6.5 Td.

Toolinard your engine should be of the more desirable castings, crank etc. I would suggest new bearings if at all feasible before the install. Keep us updated.
 
The pumps were the same but if I recall correctly the pick up tubes were different. I dunno. It all worked out. If anyone wants a humvee oil pump, I have one in the shop somewhere.

I want to encourage the original poster to assess the engine before dropping it in to a truck. The gov likely didn't ditch it for no reason. Something is likely wrong with it. The trick is finding out what is wrong with it.

Mine had a spun rod bearing, most notably number 7, although everything from 5 back was damaged. A compression check indicated something hinky with number 7. I pulled the heads and found this this.

Before http://www.youtube.com/watch?v=NpvmQImAwjs

After http://www.youtube.com/watch?v=7c6FIcEE2GI


Good times!
 
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