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Seeking info on engine block numbers on CJ2-A

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csparks View Drop Down
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    Posted: 20 Jan. 2022 at 11:22am
Hi again. Recently got some good info on here for a neighbor that is restoring a CJ2-A. 

The block was cracked on his original motor, and we located a parts CJ2 A on this site. He is now curious about the numbers stamped on the side of the motor.

I typed a long message, posted photos, then ended up losing the whole thing. So, I'm not trying photos again. The parts motor looks a bit "beefier" than the old motor, heavier bell housing, etc.

The number on the first, cracked block is:
641087-L-W10A NI-ch N2

The new parts cj motor:
641087-W-12_D-P5-CU-CH

I guess he's mostly interested in year, but not sure if other info can be discerned from these numbers.
Lastly, if anyone knows an experienced Willys motor rebuilder in Oklahoma, that would be a plus.

Thanks for patience.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Joe Friday Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan. 2022 at 11:36am
Those are casting numbers.

The engine serial is stamped on a flat spot above the water pump.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csparks Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan. 2022 at 11:44am
Ah, thanks. 

I guess those were more for old internal record keeping or something. 

From the serial, would you be able to know the year, etc?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mbullism Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan. 2022 at 12:52pm
I'm no expert, but the casting did undergo updates throughout it's production... your problem is that the 641087 block had a pretty good run and by itself won't narrow it down to the decade let alone the year.  I'm pretty sure the "W##" was the bay in the foundry, W for Wilson Foundry... I always thought the rest had to do with the chemical makeup of the cast iron, ie Ni ch = nickel chromium, etc... but either way it won't tell you a year.

The serial number will (should) have a prefix that will help identify which model vehicle it started life out in, and the digits that follow can be plugged into serial number ranges by year for each model.  Any letters at the end of the ESN have to do with machining that was done to the block, again not much help with the year.

On earlier blocks you'll find a machining date stamped into the oil pan rail back by the rear main bearing cap/seal, but I can't recall if that practice carried up into the 641087 block-

So, yes the ESN is your best starting point... 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csparks Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan. 2022 at 1:37pm
With that info about 641087, I've google and found multiple threads about the engine blocks. Both here and other forums.

There's an old service bulletin here that sheds some light. 

I'll look over those serial numbers next visit down to the Willy's Restoration Project.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan. 2022 at 1:41pm
Originally posted by Joe Friday Joe Friday wrote:

Those are casting numbers.

The engine serial is stamped on a flat spot above the water pump.


This is assuming that it hasn't been removed by "decking" the block.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bruce W Quote  Post ReplyReply Direct Link To This Post Posted: 20 Jan. 2022 at 4:41pm
Originally posted by SE Kansas 46 CJ-2A SE Kansas 46 CJ-2A wrote:

Originally posted by Joe Friday Joe Friday wrote:

Those are casting numbers.

The engine serial is stamped on a flat spot above the water pump.


This is assuming that it hasn't been removed by "decking" the block.

  I’ve got or have seen a few with no sign of any decking or any other machine work with no stamped number. I’ve also never found a machining/assembly date stamped on the pan rail of a 641087 block. 
BW 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TMRoper Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jan. 2022 at 6:27am
Where in Oklahoma are you?

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Post Options Post Options   Thanks (0) Thanks(0)   Quote csparks Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jan. 2022 at 7:32am
Near Stroud, right smack in the middle of the state.

That first motor block had evidently been bored out, and over time the cylinder wall cracked. So, he got the parts Willys mostly on the hope the block was OK on it. So far, there are no red flags.

He's a pretty great mechanic type, but says he needs the block examined, and the valves done by a shop. Guess it needs to be scoped, etc.

He's got a shop in Tulsa that seems competent, but it would always be good to run across some Willys guy that really knows the Go Devil.

The days are gone when there were motor rebuilders in every good sized town. Shoot, good sized towns are getting hard to come by outside Metro areas.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Vintage Don Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jan. 2022 at 8:04am
Originally posted by csparks csparks wrote:


Near Stroud, right smack in the middle of the state.


How about that - 4 years ago, I drug my '48 pickup home a 1,000 miles from Stroud, OK! 

Then went back through there this past summer to visit with the Seller, who has become a friend.



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Post Options Post Options   Thanks (0) Thanks(0)   Quote csparks Quote  Post ReplyReply Direct Link To This Post Posted: 21 Jan. 2022 at 11:36am
Well that's crazy. I'm about 10 miles south. We're about halfway between Stroud, and Prague, OK. Basically, Sticksville.

But, we're also halfway between OKC and Tulsa, which is nice. One hour to either.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote TMRoper Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan. 2022 at 6:34am
We are in Banner,between Yukon and El Reno,if you are familiar with Guthrie there is a guy that has a machine shop and he was recommend buy a nice guy on the g503 page, I can't remember the name of it but its on the south side of the road just outside of town on the road to Kingfisher. I will see if I can find his card.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csparks Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan. 2022 at 6:43am
I'll try to run that down, thanks.

Funny you mention Banner. My wifes Grandma was born on a farm out there where Banner once was, and her parents still own the land, and always just refer to it as Banner. 

Wife's other Gradnma was from Kingfisher; other family around Okarche, and you know what that means. Fried Chicken.

Crazy world. I've actually mentioned Eishen's chicken to this neighbor before. He's never had it or heard of it. It really has grown in reputation/publicity. I kinda miss 35 years ago when we'd go out there to visit,  and be able to just walk in a carry a big sack of it out.

For others on the board, Eishen's was an old family bar/grill in the tiny town of Okarche that began frying chicken many years back. Its reputation grew, and has exploded among the Food Network types. It seems to be nationally recognized now.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote TMRoper Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan. 2022 at 6:51am
And its the oldest bar in Ok, that's saying alot ! My son and I go to the surplus store and on to Eishens, chicken so hot it will burn your mouth! Also don't forget Sids onionburgers top 5 burgers in the us! If your passing through, stop by great to visit with willys guys!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Joe Friday Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan. 2022 at 11:39am
Quote

  I’ve got or have seen a few with no sign of any decking or any other machine work with no stamped number. I’ve also never found a machining/assembly date stamped on the pan rail of a 641087 block. 
BW 

Bruce, I agree, there are some that were not stamped.

Willys tabulated a list (drawing 911911) that gave a specific part number to the engine and configuration for each engine assembly. Each part number had a 40+ page manufacturing and assembly list that included the instructions to stamp the block, and where to sign out the range of engine serial numbers and prefixes for each.

IF Willys followed their process, the undecked engines you have seen without engine numbers stamped were sold as bare blocks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csparks Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan. 2022 at 5:39pm
While I've got you guys. We've been looking at these motor blocks. On the front, along the bottom the block is oval/curved to accomodate the crankshaft or transmission or something. Just above that, sticking out of the block is some kind of a hexagonal bolt looking thing. Sticks out about 1-2 inches. It has what looks like a slot for a flathead screwdriver on face of it.

I obviously have no idea what this idea, but neither does my more mechanical neighbor. It looks like its designed to be able to put a wrench to it, but what for?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan. 2022 at 7:01pm
It is the oiler for the crank to cam drive gears. there should be a small hole on one of the flats that line up with the slot. It is supposed to align with the intersection of the gears. The hole should measure about .040" but it could measure .070".*** Willys put out a service bulletin sometime in the late 40's directing that the hole be smaller. Some were converted and others were not.

***This post has been edited to correct an error! I sincerely apologize for the misinformation that I posted earlier. Sharp eyes caught the error and called me on it. Call it old age brainfog.

Edited by SE Kansas 46 CJ-2A - 23 Jan. 2022 at 9:55am
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jan. 2022 at 8:41pm
WHOA WHOA THERE

The service bulletin to reduce the size of the Oiler orifice down to .040 so as to help improve oil flow to the #1 rod bearing. 
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