M38 motors |
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jpet
Moderator Group Sponsor Member x 5 Joined: 30 Apr. 2008 Location: Ramsey, IL Status: Offline Points: 11173 |
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Posted: 12 Jan. 2010 at 2:51pm |
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Why would some M38 motors be stamped MCXX.... and some be stamped RMCXX....?
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CJ2A #29110 "General Willys"
MB #204827 "BAM BAM" "We do what we can, and we try what we can't" |
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jpet
Moderator Group Sponsor Member x 5 Joined: 30 Apr. 2008 Location: Ramsey, IL Status: Offline Points: 11173 |
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I found this thread where Gale says that the "R" probably stands for rebuild.
Can anyone confirm this?
The MB that I have has an MC motor. "RMC15268" I am trying to determine if it would be possible that the motor was put in by military personnel while the vehicle was still in service or was it definitely replaced by a civilian after service. Edited by jpet - 12 Jan. 2010 at 3:12pm |
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CJ2A #29110 "General Willys"
MB #204827 "BAM BAM" "We do what we can, and we try what we can't" |
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bkreutz
Member Sponsor Member Joined: 17 Oct. 2006 Location: Fruitland Idaho Status: Offline Points: 7037 |
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MC would be the prefix for an original engine, the "R" would indicate a replacement. MC being the designation for a M38 (following the military model designation sequence, MB being the WWII version, and MA the model before that)
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jpet
Moderator Group Sponsor Member x 5 Joined: 30 Apr. 2008 Location: Ramsey, IL Status: Offline Points: 11173 |
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Edited by jpet - 12 Jan. 2010 at 4:34pm |
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CJ2A #29110 "General Willys"
MB #204827 "BAM BAM" "We do what we can, and we try what we can't" |
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bkreutz
Member Sponsor Member Joined: 17 Oct. 2006 Location: Fruitland Idaho Status: Offline Points: 7037 |
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I've always thought the "R" prefix was a replacement not a rebuild, so to answer your question (at least as far as I know) The "R" would be a new motor. I'm remembering motor pool rebuilds had a separate rebuild tag attached somewhere else.
Edited by bkreutz - 12 Jan. 2010 at 5:36pm |
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jeepfreek
Member Joined: 23 Feb. 2009 Location: arnprior ontario Status: Offline Points: 191 |
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hi.i believe gale is right.r is for replacement.when new jeeps were ordered a supply of parts was also ordered along with replacement engines.regards jim.
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cj2a-6,mb-7,cj5-1,m38-3,m38a1-5
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jpet
Moderator Group Sponsor Member x 5 Joined: 30 Apr. 2008 Location: Ramsey, IL Status: Offline Points: 11173 |
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What can you tell me about the 15268 number after RMC?
I guess what I am trying to do is decide whether or not to keep the motor. If I could determine that there is a reasonable chance that the motor was put in by a military mechanic while the vehicle was in service, I would want to keep it. If the motor was most likely put in after service by a civilian, I would certainly replace it with one that was more "numbers matching".
Maybe it is impossible to do. I can't seem to find M38 motor data like what we have here on 2A motors. Edited by jpet - 12 Jan. 2010 at 6:17pm |
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CJ2A #29110 "General Willys"
MB #204827 "BAM BAM" "We do what we can, and we try what we can't" |
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Viking
Member Joined: 29 Oct. 2009 Location: Frogner/Norway Status: Offline Points: 173 |
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Hi Jpet.
As earlier said in this tread:
Willys MA = Military modell A. Engine block casting number: 638632
Willys MB = Military modell B. Engine block casting number: 638632
Willys MC = Military modell C. Engine block casting number: 641087 up to s/n 74419 then 804380.
What is the casting number on your block?
I have no info/proof about RMC, but it would be interesting to see if the stamping was done at the "same" time.
If the R was stamped in later than the MC I would say Rebuild, but if the RMC was stamped at the same time I would guess "R" was placed there to indicate a replacement engine.
again....NO PROOF, just my thoughts.
You will find a couple of photos here: http://ww2jeeps.com/htm/willysmc.htm
The serial number on your block (15268) puts it in the "early" period. There is supposed to be a change in the aft part of the block to improve sealing when fording on the late blocks.
Edited by Viking - 14 Jan. 2010 at 9:10am |
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Frank..
CJ2A s/n 18526 41-45 Willys MB`s 42-45 Ford GPW`s Bantam T3 and Willys MBT CJ-7 x 2 YJ, TJ and JK |
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jeepfreek
Member Joined: 23 Feb. 2009 Location: arnprior ontario Status: Offline Points: 191 |
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hi jpet.i talked to the guru on m38 jeeps around here in ontario today.he says the r stands for replacement.the serial no is just a seq. no that he says did not have a lot of meaning.regards jim.
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cj2a-6,mb-7,cj5-1,m38-3,m38a1-5
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leomartin6
Member Joined: 28 Apr. 2010 Status: Offline Points: 1 |
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I have found a lot of useful stuff from here. I mean it is helpful from the technical point of view to use practically.
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BillF
Member Joined: 02 Oct. 2005 Location: Hillsborough NH Status: Offline Points: 1133 |
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Yes the R stands for replacement. I have an RMC engine in my m38. The numbers after the RMC are the engines serial numbers.
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1952 m38
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mazeem1234
Member Joined: 04 July 2011 Status: Offline Points: 1 |
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Hi,
it's very great informative stuff shared here useful one for many others who needs this kind of stuff,… i appreciate this effort,.. best regards,.. ---------------------------------------------- hairstyles Edited by sean - 10 Nov. 2011 at 1:35pm |
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m38mike
Member Joined: 23 Apr. 2007 Location: Colorado High Country Status: Offline Points: 3796 |
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Jpet, the info you're getting here is spot on, R is replacement, and was put in after the vehicle entered service. The problem with your quest to know if it was put in during service or after service is that many replacement blocks were sold as surplus when the military phased out the M38 in the 60's. There is no definitive way of telling when the block was installed, but it very well could be military replacement. One thought for investigating it is to look at all the connections to see if they are all done "text-book" or if they've been "modified". If all the plumbing is text book, then it's either a meticulous mechanic, or a military one following the maintenance guide. If not, it could be a "fix" by a shade-tree mechanic, or an install by a less exacting weekend mechanic.
BTW if you decide to sell, there is a demand for MC blocks in the M38 crowd. There simply were not many made.
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M38Mike
46 CJ2A SAMCJ2A 4?-5? CJ2A/3A/M38 Jigsaw 51 M38 Green Jeanne 52 M38 Blue Mule, 51 M100 Blue Mule Tale 52 XM38EV1 Electro-Willys, 52 M100 Juice Box |
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jpet
Moderator Group Sponsor Member x 5 Joined: 30 Apr. 2008 Location: Ramsey, IL Status: Offline Points: 11173 |
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Well here is the engine stamp:
I can't tell if the "R" was stamped in later or not. Interesting enough, today I found that the motor also has a rebuild tag: Now what have we learned if anything? |
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CJ2A #29110 "General Willys"
MB #204827 "BAM BAM" "We do what we can, and we try what we can't" |
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52 M38
Member Joined: 26 Nov. 2012 Location: New England Status: Offline Points: 1286 |
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JPET, this is only other tag like mine i have ever seen. Mine said Aberdeen on it instead, and it was hemi orange, just like the rest of the engine. I have no idea why it would be orange. |
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