HELP!! M38A1 Timing
- Bugler
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- wesk
- Site Administrator

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Did you run the engine to determine it is 180 out?
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. ... _album.php
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. ... _album.php
- Bugler
- Member
- Posts: 14
- Joined: Sat Mar 01, 2014 6:00 pm
- Location: Paradise, CA
- Contact:
- wesk
- Site Administrator

- Posts: 16467
- Joined: Sun Apr 03, 2005 6:00 pm
- Location: Wisconsin
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The only problem with your conclusion is the distributor only fits one way so a 180 degree error is only possible if you have the wrong cylinder at top on compression IE have #1 at top on it's exhaust stroke.
Let's look at what we covered earlier.
1 - #1 TDC on compression. This done using your thumb over the spark plug hole. Don't rely on the two gear marks.They line up twice each cycle. Once on Compression and Once on Exhaust! If you err and set everything with #1 TDC exhaust then yes you will be 180 deg's off.
2 - The oil pump indexing then matches the illustration.

3 - Then the distributor rotor points to the correct lower

4 - The wires are arranged correctly per the illustration.

You must meet these four requirements in the order posted for the timing to end up correct.
Let's look at what we covered earlier.
1 - #1 TDC on compression. This done using your thumb over the spark plug hole. Don't rely on the two gear marks.They line up twice each cycle. Once on Compression and Once on Exhaust! If you err and set everything with #1 TDC exhaust then yes you will be 180 deg's off.
2 - The oil pump indexing then matches the illustration.

3 - Then the distributor rotor points to the correct lower

4 - The wires are arranged correctly per the illustration.

You must meet these four requirements in the order posted for the timing to end up correct.
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. ... _album.php
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. ... _album.php
- Bugler
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- Location: Paradise, CA
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- RICKG
- Jeep Legend

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- Bugler
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- 4x4M38
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Just wanted to thank Wes and the rest of the folks for again
providing quality information.
My son in laws CJ5 was out of time. He couldn't find the timing
marks and the distributor would not move far enough to set the
advance properly.
I found this post with timing info on the A1, found the three versions
of the timing marks, which we used to find the stamped info
on the cover.
Further reading explained the need for clocking the oil pump
correctly. He loosened the pump, turned the gear one tooth,
bolted everything up tight and now the distributor has equal
adjustment either side of TDC.
After I left he set the advance, connected everything back up
connected a timing light, reset the advance and the jeep is
running great !
Thanks again.
Brian
providing quality information.
My son in laws CJ5 was out of time. He couldn't find the timing
marks and the distributor would not move far enough to set the
advance properly.
I found this post with timing info on the A1, found the three versions
of the timing marks, which we used to find the stamped info
on the cover.
Further reading explained the need for clocking the oil pump
correctly. He loosened the pump, turned the gear one tooth,
bolted everything up tight and now the distributor has equal
adjustment either side of TDC.
After I left he set the advance, connected everything back up
connected a timing light, reset the advance and the jeep is
running great !
Thanks again.
Brian
