Engine Cj2a10973-b |
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McG
Member Joined: 07 Jan. 2013 Location: White Hall, MD Status: Offline Points: 243 |
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Posted: 05 Apr. 2018 at 11:59pm |
mbullism
Member Sponsor Member x 4 Joined: 29 May 2015 Location: MA Status: Online Points: 4760 |
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The B means 0.002" oversized cylinder bores from the factory
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Those who do not learn from history are doomed to repeat it... Welcome to 1930's Germany
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lowenuf
Member Sponsor Member x 2 Joined: 29 Aug. 2006 Location: Ohio Status: Offline Points: 9119 |
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Actually, the factory never bored the cylinders. If the serial number was followed by an "A" or a "B", it designated that either the rods or the mains were over sized respectively.
And as an FYI, this engine is currently being held with a down payment, to soon be heading to my place... Edited by lowenuf - 07 Apr. 2018 at 5:59pm |
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45 #10012
45 #10033 ACM #47 45 #10163 ACM #188 57 CJ5 Dauntless V6, T-18 4-speed, D-44 rear/D-30 front, D-20 twin stick |
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McG
Member Joined: 07 Jan. 2013 Location: White Hall, MD Status: Offline Points: 243 |
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glad it is headed to another from the 2a page. Might this be a replacement for the v6?
Now if I could just find one around s/n 60000.......
Edited by McG - 08 Apr. 2018 at 11:52am |
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mbullism
Member Sponsor Member x 4 Joined: 29 May 2015 Location: MA Status: Online Points: 4760 |
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1948 mechanics manual...(ETA: fwiw, the 1955 MM says 0.010" over)
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Edited by mbullism - 08 Apr. 2018 at 12:35pm |
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Those who do not learn from history are doomed to repeat it... Welcome to 1930's Germany
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lowenuf
Member Sponsor Member x 2 Joined: 29 Aug. 2006 Location: Ohio Status: Offline Points: 9119 |
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hmmmmmm, never seen that before..... interesting..
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45 #10012
45 #10033 ACM #47 45 #10163 ACM #188 57 CJ5 Dauntless V6, T-18 4-speed, D-44 rear/D-30 front, D-20 twin stick |
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Joe Friday
Moderator Group Sponsor Member x 2 Joined: 26 Dec. 2010 Location: Jeep Central Status: Online Points: 3633 |
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The factory BOM for MB engines is about 25 pages of 'oddball' parts including very slight oversize pistons, rings, Wrist pins etc. Some were for field fixes, some were for factory salvage blocks.
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Ol' Unreliable
Member Joined: 25 Sep. 2016 Location: CO Springs CO Status: Offline Points: 4226 |
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It seems weird that they would overbore the cylinders by just two thousandths of an inch. Why not go ten thousandths?
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There's a reason it's called Ol' Unreliable
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mbullism
Member Sponsor Member x 4 Joined: 29 May 2015 Location: MA Status: Online Points: 4760 |
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My guess is at .002 they used a standard piston with over sized rings... the later mechanics manual and service manual both say .01" over, so maybe the moved away from that-
ETA: also guessing this wasn't anything other than a way to use otherwise out of tolerance parts (?)
Edited by mbullism - 08 Apr. 2018 at 11:55pm |
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Those who do not learn from history are doomed to repeat it... Welcome to 1930's Germany
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Ol' Unreliable
Member Joined: 25 Sep. 2016 Location: CO Springs CO Status: Offline Points: 4226 |
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Apparently Willys pinched their pennies more than I would have expected.
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There's a reason it's called Ol' Unreliable
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cpt logger
Member Joined: 23 Sep. 2012 Location: Western Colorad Status: Offline Points: 3022 |
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Good guess! That is exactly what they did. If you know where to look, you can still find oversized rings for many of the old engines. Most manufacturers of that era did some of this. The tractor & truck manufacturers used this quite a bit to use up parts that were out of specifications. Aircraft engine manufacturers also used this process to use parts that otherwise would be scrap. Keep in mind that we did not have the precision casting & machining capabilities that we have now. I have heard that the scrap rate was close to 25% of the total manufacturing. While that seem awful high, most of the engineers from that era that I spoke to in the past, confirmed the 25% number. All of them have passed on now. |
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