M38A1 - setting proper timing.

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pduske
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Posts: 30
Joined: Tue Jan 31, 2006 6:00 pm

M38A1 - setting proper timing.

Post by pduske »

Hi fellows,

I am facing the following problem:
- I installed a rebuild distributor built from nos parts.
- using a stroboscope lamp, running with approx 800rpm, I turned the distributor clockwise. But even when reached the maximum possible angle (the distributor housing then is horizontal) I do not reach the 5° marking on the housing.

- Interestingly the wires are not positioned as they should:

https://drive.google.com/uc?export=down ... iKDNF9bhwi

Would it help to switch wire "1" to wire "3" counterclockwise and simultanelously turn the distributor counterclockwise also? I should be able to reach the 5° tdc marking then, correct?

Or what is the best way to reach 5° befor tdc?

I appreciate your help!

Philipp
´57 M38A1
Ramsey 50R setup
USMC spec. PowrLok front & rear
Meyer ST 84 plow
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wesk
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Post by wesk »

Philipp,

First the oil pump must be indexed correctly with #1 piston TDC on compression since the oil pump is driven by the cam and the oil pump drives the distributor. This is the most overlooked step in final engine assembly on this planet. It is not that critical on civilian jeeps because they use a distributor with a small round housing. The much larger oval housing of the military distributor will contact the block before it can be rotated far enough to set timing correctly if the oil pump is not first indexed correctly.

Image

Second the cap wire sequence is incorrectly illustrated in TM 9-8014 Fig 79.

Image


Please go to my photo album: http://www.willysmjeeps.com/v2/modules. ... php&page=2
and review my ignition timing album: http://www.willysmjeeps.com/v2/modules. ... _album.php The two photos above are from this album. Review this album carefully.
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
Eades
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Posts: 97
Joined: Mon Jul 09, 2018 6:00 pm
Location: Western Washington

Post by Eades »

I attempted to set it close before I ever started mine. My engine had been rebuilt and never ran. I could not get close to the proper setting. I realized the oil pump shaft was set 180 degrees opposite of correct. Off came the pump, turned the shaft 180, and good to go.

Yours is probably indexed incorrectly. Follow the TDC instructions to find out.
Rick Eades
1951 M38 & 1967 M715
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