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Is the military junior filter same for both mb gpw and m38 engine.
As I understand the mb has no Oiler fitting inside the timing chain cover and the oil pressure is regulated by a small hole inside the oil filter canister.
The M38 has a Oiler fitting inside the timing cam cover that regulates oil engine pressure.
My question is in regards to the hole size inside the filter canister for chain drive vs the gear drive engines.

The WWII Military junior filter is the same unchanged military junior used on the M38 pilot jeeps and the M38A1.

No real concern. The WWII chain drive engines had to have the filter installed so oil would return from the filter and coat the chain. Only purpose for the oil return hose from the filter on gear driven cam engines is to get the oil back to the sump. The gear driven cam engines care not how much oil flows back to the sump thru the oil return hose from the filter.

However the M38 blocks prefer the newer cam gear oil spray nozzle. Willys decided too many #1 rod bearing failures were being attributed to the 0.070 bore spray nozzle allowing a drop in oil pressure at the front of the crank. Willys brought a new nozzle into production with a 0.040 bore to sole the issue.

The change notice on the spray jet is at top Left of this page.

Thanks for the information