I took my recently alive M-38A1 out to see how it drove, backfiring thru carb (Minor) and no real power. So I took it home and decided I would run a timing light on it to see if that would improve things.
The Distributor is all the way Counter clockwise as far as I can get it (It is bumping against the Generator). So I pulled the distributor and looked at the orientation on the oil pump. It looks good as far as I can tell. I have plenty of adjustment clockwise (Toward the rear block), just none Counter.
I am thinking that the oil pump may be off one tooth. So I am thinking of pulling the pump and spinning it one tooth over. This theoretically should give me a bigger range of adjustment...
Thoughts please, supposed to rain tomorrow so got a few days to think this over...
_________________ Hal, KB1ZQ
TSGT, USAF (Ret)
1952 M-38 CDN CAR 52-31313
1952 M-100 Strick #104
1951 Willys Wagon (For Sale)
1954 Willys M38A1 201001205
Tornado Alley
Del City, OK
The index illustration for the top of the oil pump drive is based on a very precise placement of #1 cyl TDC with the two "0" marks on the cam gear and crank gear perfectly aligned. The only way to assure you are in the correct place with the pump gear shaft is with the timing cover removed to confirm the placement of the two "0" 's on the cam gear and crank gear. This is very clearly spelled out in TM 9-8015-1, page 115, para 101.
What you are trying to do is to assume someone set the cam gear to crank gear correctly and just got the oil pump clocked wrong during it's installation. You may get lucky and get your ignition timing adjustment closer to correct but your basic valve timing may still be in error. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Jul 10, 2018 Posts: 97 Location: Western Washington
Posted: Mon Apr 26, 2021 7:21 pm Post subject:
The oil pump could be off a tooth. My personal experience was when my engine was rebuilt and reassembled the pump was installed 180 degrees off. It had never ran. I finally figured that out when pulling my hair out trying to start it and properly clocked it. I then had the same issue you described with only being able to adjust distributor one way. I pulled the oil pump again and bumped it over one tooth and all is well now. I am able to advance or retard the timing now. _________________ Rick Eades
1951 M38 & 1967 M715
Joined: Oct 02, 2014 Posts: 2009 Location: South Carolina, Dorchester County
Posted: Mon Apr 26, 2021 9:29 pm Post subject:
Hi Hal,
Without comparing both M38 and M38A1 manuals that both tell how to correctly assemble the motor ----- isn't clocking the oil pump, distributor, and timing gears exactly the same for both the F134 and the L134 motors?
You have both motors? Assuming your M38 is up and running good ---- it ought to be fairly easy to get the F134 straightened out?
I could be mistaken, but isn't correctly clocking the oil pump, distributor, and timing gears exactly the same for both the F134 and the L134 motors?
That is correct!
Hal, Just for the heckuvit post a photo of the plug wire arrangement in your distributor cap. I ask because the M38A1 service manual has an incorrect wire arrangement that was corrected by two separate changes but these changes never seem to be in the manual copy on hand.
Joined: Feb 17, 2012 Posts: 530 Location: Del City, OK
Posted: Tue Apr 27, 2021 7:08 am Post subject:
I know #1 Plug is in the Lower left position, I will double check the rest just to be sure. (Edit - Just checked the rest, #2 and #3 were swapped it is now set to 1,2,4,3 going in a CCW direction).
The photo I posted is my current position of the oil pump.
As for the timing gears on the crank and cam, I set those long ago as I know how important they are.
I learned a lot on my M-38CDN, and this one went a lot better, but just cannot get any adjustment on the distributor...
Will continue later today have appointments this AM...[/b] _________________ Hal, KB1ZQ
TSGT, USAF (Ret)
1952 M-38 CDN CAR 52-31313
1952 M-100 Strick #104
1951 Willys Wagon (For Sale)
1954 Willys M38A1 201001205
Tornado Alley
Del City, OK
Joined: Feb 17, 2012 Posts: 530 Location: Del City, OK
Posted: Fri Apr 30, 2021 10:44 pm Post subject:
Sorry, been busy I have a reasonable adjustment range now, Power connector is about 1.5 inches from the generator and plenty of room to go the other way.
Was under the jeep today and reformed the ends of the fuel lines. Making sure the flares were straight and able to seal properly.
Ran out of time so will test run it tomorrow to see if it leaks... _________________ Hal, KB1ZQ
TSGT, USAF (Ret)
1952 M-38 CDN CAR 52-31313
1952 M-100 Strick #104
1951 Willys Wagon (For Sale)
1954 Willys M38A1 201001205
Tornado Alley
Del City, OK
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