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Balvar24 Member
Joined: Sep 05, 2009 Posts: 191
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Posted: Sat Jun 25, 2011 8:16 pm Post subject: Crankshaft Question |
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Did the L and F head use the same crankshaft? |
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16282 Location: Wisconsin
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Balvar24 Member
Joined: Sep 05, 2009 Posts: 191
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Posted: Sat Jun 25, 2011 8:24 pm Post subject: |
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Earlier L heads used a different Crank? Any way to visually tell the difference? I've got a line on a bargain, but need to be sure. |
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16282 Location: Wisconsin
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Posted: Sun Jun 26, 2011 7:46 am Post subject: |
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Earlier L134's had chain drive cams and the crank was different.
The MA/MB 638121 timing chain crank had counter weights that were very narrow when compared to later bolted counterweight cranks. .This crank is easy to spot.
The second timing chain crank 641128 had bolt on counter weights introduced on the CJ2A and was often a service spare for the MB/GPW.
Then came the 646316 gear drive cam crank with bolt on counterweights.. The bold underlined area was edited to correct crank data.
The obvious difference on the cranks will be at the front. Photograph and measure you crank snout area and use it to confirm compatibility.
Another thing to watch for is the use of two tapered dowel bolts or two straight shouldered dowel bolts at the rear flange. Your choice will depend on what you currently have in your flywheel. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php
Last edited by wesk on Mon Jun 27, 2011 11:30 pm; edited 2 times in total |
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AeroE Member
Joined: Aug 31, 2008 Posts: 49 Location: SE MN
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Posted: Mon Jun 27, 2011 8:12 pm Post subject: |
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Wes: your comment on crankshaft evolution intrigued me in that I have what I believe is an NOS M38 crankshaft, still in cosmoline. It looks right, the bearing dimensions are correct for standard bearings, the cam drive gear (NOS) seems to fit nicely, and it looks just like the crank in TM9-1804A page 53. Except it definitely has bolt on counterweights, with a single allen head bolt each. ORD 9 lists the part as ‘Crankshaft, with counterweights’ implying that are an added part. Page 53 also shows the bolts clearly.
If I understood you said only early MA/MB crankshafts have bolt-on counterweights, what do I have? |
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Balvar24 Member
Joined: Sep 05, 2009 Posts: 191
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Posted: Mon Jun 27, 2011 8:22 pm Post subject: |
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The later F heads had bolt on weights as well. Mine were bolted on and tack welded in place. I think that only the later chain drive cam engines had integral weights while later gear driven cam engines had bolt on.
Would you be interested in parting with your crank? If so, feel free to send me a PM. |
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AeroE Member
Joined: Aug 31, 2008 Posts: 49 Location: SE MN
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Posted: Mon Jun 27, 2011 8:48 pm Post subject: |
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I thought I may have misinterpreted what Wes said.
I still would like to confirm. Since the manuals only list the crankshaft bearing journal dimensions, it would help if someone posted the length x diameter of the cam gear portion of the shaft. A photo of the correct snout would be great! |
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wesk Site Administrator
Joined: Apr 04, 2005 Posts: 16282 Location: Wisconsin
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Balvar24 Member
Joined: Sep 05, 2009 Posts: 191
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Posted: Tue Jun 28, 2011 7:09 am Post subject: |
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Thanks. That's an immense help. |
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