Burning oil

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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Shug4
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Burning oil

Post by Shug4 » Sun Apr 11, 2021 6:47 am

I noticed last year after I had the head rebuilt that after a month I was burning oil. I replaced the pcv on it and it looked like it might have stopped. When I got it out this year it ran like a dog. I took out the plugs and noticed the third cylinder was burning oil. Going to take a compression check next week. Can anyone tell me all the problems that would cause this to burn oil on the third cylinder. The 1952 m38a1 has only about 35000 on the engine. Would appreciate any answers. Thanks


captaincarrier
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Re: Burning oil

Post by captaincarrier » Sun Apr 11, 2021 9:10 am

Your new head job is sucking oil past the rings....

ndnile
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Re: Burning oil

Post by ndnile » Mon Apr 12, 2021 7:10 am

Some one more knowledgeable then me will step in, but until then .....

I'm not sure that 35,000 miles would be considered low-time.
Due to gearing, these engines do a lot more revolutions per mile than anything short of a tractor would.
Due to the long piston stroke, the rings have to travel more distance up and down the cylinder walls on each stroke which increases wear.
Due to low HP, we often run these much closer to their max rated power than we would a modern car.

WRT reasons why the 3rd cyl is using oil. Your upcoming compression test will be a useful thing here.
* If compression is good then I would suspect the intake valve stem not sealing.
* If compression is low then I would suspect rings. You can also look for signs of blow by as another sign of this.
Doug
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1943 GPW-125334 (Sold)
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Shug4
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Re: Burning oil

Post by Shug4 » Fri Apr 16, 2021 11:42 am

Going to take a compression test this weekend along with a leak down test. If they show good then I will take the head off and check the head gasket.

Joe Gopan
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Re: Burning oil

Post by Joe Gopan » Fri Apr 16, 2021 2:18 pm

The average well cared for Jeep Engine starts consuming oil around 30,000 miles. Your excess Oil consumption may be due to uninstalled or improperly installed 800986 Intake Valve Oil Stem Oil Seals (AKA Packings). I doubt it tho. There is only one correct order to install these 4 seals on the intake valves.
Consult your "F"-134 Manual on how to install these.
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Shug4
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Re: Burning oil

Post by Shug4 » Thu Jun 10, 2021 3:55 am

That's what I was thinking. I took head off last week and just last night took valve springs off. Found out that the company that did the valve job didn't put the little round stem seals on. Will put them on and put back together to see if that works.


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