Oil filter opertion

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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Hanselandgretel
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Oil filter opertion

Post by Hanselandgretel » Tue Jun 11, 2019 8:12 pm

I am working on a PE95 generator with a Jeep engine and Mil Standard Jr oil filter. My question is how does the oil get out of the filter? Oil enters the side and is supposed to leave by the bottom center hole, but I can see no way the oil can get to the center hole. The center "pipe" is closed at the top by the cover bolt. The bottom of the center "pipe" connects to the exit hose. When I fill the canister with oil and remove the bottom hose, nothing runs out??? When I plug one end of the center "pipe" and blow air in the other end, there is no air escaping the center "pipe". How does the oil exit the filter? Thanks

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Re: Oil filter opertion

Post by Ben Dover » Wed Jun 12, 2019 5:09 am

Leave the cover off, turn the empty filter upside down and blow high pressure air into the bottom fitting. Set it on a rag to catch any splatter.
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Hanselandgretel
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Re: Oil filter opertion

Post by Hanselandgretel » Wed Jun 12, 2019 6:18 am

Thanks Joel. Does that mean there should be a hole in the side of the center pipe and it is plugged? Center pipe itself is clear top bolt hole to bottom hose fitting, I can see through that.

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Re: Oil filter opertion

Post by Ben Dover » Wed Jun 12, 2019 7:50 am

There is a tin spacer at the bottom that the cartridge rests on, the hole is way down there in the side of the tube. The hole is calibrated and very small so that oil pressure is maintained and not gushing back thru the timing cover unrestricted.
I would be surprised if it were plugged.
I always take a rag or paper towel and wipe that bottom space dry after oil changes.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

Hanselandgretel
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Re: Oil filter opertion

Post by Hanselandgretel » Thu Jun 13, 2019 7:31 pm

Thanks for the help. When I blew air through the center pipe I unplugged the hole, small one, about 1/2 way up on the center pipe. I understand now how the oil circulates! I appreciate the help. Al Hansel


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Re: Oil filter opertion

Post by James L » Fri Jun 14, 2019 4:52 pm

I checked a motor at my shop today and found the very small hole in the center tube. My hole is about 2 inches from the top of tube down and yes it is very small, a small paper clip just barely fit.

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Re: Oil filter opertion

Post by artificer » Fri Jun 14, 2019 7:25 pm

John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Oil filter opertion

Post by Ben Dover » Fri Jun 14, 2019 10:04 pm

Nearly 600,000 Jeeps were made during WWII with Military Jr. Oil Filters by PurOlator and Fram, there were thousands of PE-95 engines and other misc WWII Jeep engines also using Mil Jr filter. Willys used a smaller Fram Oil Filter on CJ-2A thru CJ-5 Jeeps . All had same design with the hole designed to restrict oil flow in order to maintain oil pressure. It was simple and it worked.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
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