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Oil filter question
Posted: Sat Jul 07, 2012 12:23 pm
by Herrmann_Sherman
In the next days I will change the oil of my M38/CJ-3A mixture. I also will change the oil filter.
My question is as follows:
Is the M38 oil filter the same as on the CJ-3A or are they different?
Thank you for an answer
Herrmann_Sherman
Posted: Sat Jul 07, 2012 1:12 pm
by wesk
From the Willys factory the M38 used a CUNO style oil filter and the CJ3A used a Fram cannister oil filter. The military eventually swapped most of the Cuno's for the old Military Junior cannister filters made by Fram, Puralator & AC. These were used on the WWII MB/GPW and the M38A1's from mid 1953 and on. The civilian Fram is a different creature and uses a different element.
M38 with original correct Cuno oil filter.
M38A1 with Cuno oil filter.
M38A1 engine with Military Junior oil filter.
Here's the assortment of civvy oil filters used on the CJ2A & 3A.
Here's a civvy Fram on an early CJ3B.
The Military Junior filter is on the left and the CJ civvy filter on the right.
Posted: Sun Jul 08, 2012 8:43 am
by Herrmann_Sherman
So I hope that I can tell my dealer that I have an Military M38 filter?
The top is stamped
"MILITARY STANDARD FILTER"
"COVER ASSEMBLY 25791"
"PUROLATOR PRODUCTS INC."
Posted: Sun Jul 08, 2012 9:08 am
by Oldsalt
If you have the military size filter it is a Fram C-4 or equivalent. The local parts places won't usually have a listing for a military jeep. If it is the civilian size they will have a listing for a CJ3A.
Posted: Sun Jul 08, 2012 9:51 am
by wesk
Several manufacturers produced the military junior for the military. Most common are:
Fram used C-21
Puralator used PD-51
AC used C-26
There are a couple dozen replacement numbers that will work. Caution with the gasket size. Some of the elements that will fit have a wrong size gasket with them.
Here's a good thread on these:
http://g503.com/forums///viewtopic.php? ... highlight=
The best list in that thread is:
Jeep Oil Filters (Confirmed)
AC P115
Allcar AC21
Apollo P70
Atlas P70
Bowser Briggs BC4
Cam2 P70
Car Care Parts C21
Champ P70
Deutsch P70
Facet Automotive LC21
Ford-New Holland C7NN6N605A
Fram C21
Fram C21P
Fram C4
Fram C4P
Hyster 57041
Kendall LC21
Knecht EN1100
Knecht ENC305
Luber-Finer P70
Minit-Lube P70
NAPA Gold 1100
Onan 12224
Phillips 66 P34
Pronto LC21
Purolator P34
Purolator P3400
Purolator P34W
Quaker State QSC4P
STP P70
Valvoline LC21
Wix 51006
Wix 51100 (same as 51006, but bigger/thinner gasket)
Wix PC1F
Jeep Oil Filters (Unconfirmed)
Baldwin C41F
Baldwin C53MJ
Clark 89749
Crosland 481
Facet 148244
Fram CP3
Hastings C4P101
Hastings F101C
Lee 151
Purolator PD34
I have not verified the accuracy of this list!
Posted: Mon Jul 09, 2012 3:38 am
by Herrmann_Sherman
ok, guys. I´ll try it out.
Many thanks!!
Herrmann_Sherman
Dealer was sending me:
Standard Military Junior Filter
ACP-115
...and oil pressure..
Posted: Tue Jul 10, 2012 5:08 am
by Herrmann_Sherman
But I don´t understand how the circulation of the filter is working. I´ve found the inflow-line but how is the oil leaving the case???
I just can find the hose but no hole to suck the oil....
It seems that the oil pressure changed from 4 to 3,6...
and I´ve taken out some snippets of old gaskets in the housing....
Oil is Castrol Classic XL SAE 20W/50...
Posted: Tue Jul 10, 2012 8:31 am
by wesk
in thru the outer circumference of the filter element and out thru the center and then thru the center filter tube and down to the timing gear cover on the engine.
Posted: Tue Jul 10, 2012 8:37 am
by skyjeep50
Oil flows up to the filter from the oil gallery along the left side of the engine, outlet is just under the fuel pump, and then leaves the filter and goes down to the timing gear cover. There it lubes the timing gear and flows back to the oil pan.
Pic 1 is of my M38 motor with the Cuno oil filter - return line can be seen routed to the timing gear cover. Pic 2 is M38A1's motor (with shiny new motor mounts installed - had to pull the motor to get them on), the return line can just be seen routed from base of the filter housing to the timing cover.
