Moisture in Oil

Post by **wesk** » Sat Jul 07, 2012 7:56 am

All depends on weather you are restoring the jeep with or without the fording valves and the associated vent system plumbing.

If you are restoring with the fording valves to match the 52 and early 53 M38A1's then all the items in the illustrations are required.

This is the driver's side with the fording valve and plumbing

If you are not restoring with the fording valves and plumbing then you can delete items "L" , "J", "K", & "R" in my bottom illustration and replace them with two pipe thread to smooth hose nipples and a short piece of 3/4" heater hose.

This is the driver's side without the fording valve.

jeeplvr247 · Post by **jeeplvr247** » Mon Jul 09, 2012 4:45 pm

I was out of town for the weekend and away from the internet so it gave me some time to get my nose in the TM's for a few hours. I finally have a grasp of what I have/dont have on my Jeep right now.
My goal is to get my jeep running well for now and in a way which will do no permanent damage to the engine. I will eventually get it back to stock and reinstall the water fording system but that will be as funds make themselves available.
I am missing everything for the vent system that is further forward than the throttle linkages on the side of the block: all of the vent lines, the PCV valve and the vacuum pump.
The jeep is running now and seems to be fine(may be a little rich). Am I doing any damage by running it with all of these parts missing?
Also, I do not have an oil filter but I am about to instal one. Currently it only has one oil line (which bypasses the filter) and runs from the vent in the side of the block (where the PCV valve normally is located) to the normal "oil in spot". The point in the block that the oil line is supposed to come out of is currently plugged. Would it be better to unplug that hole and run the oil line like it is supposed to go or is it fine to leave it how it is and just add the filter into the system just as it is?
Keep in mind that I am not going for original right now. I am just trying to get it out on the road without doing any damage in my haste to get it around town.
Thanks for all the help, I do not know how I would make it without this forum.

Post by **wesk** » Mon Jul 09, 2012 8:23 pm

How about giving us photos of both sides of your engine just like the photos I have provided here for your reference? Your non-technical description of your existing plumbing is very hard to follow.

The engineering that went into inserting the oil filter into the engine's oil pressure system was very precise. In fact any other arrangement can cause damage to your engine. Particularly those plumbing changes you described above. There is no relationship at all between the vent plumbing and the pressure oil system. To connect them together is not a wise choice.

The oil must be supplied to the filter under pressure provided by the oil pump. The only convenient access to that pressure is the threaded port behind the fuel pump which is where the engineers connected the filter. The oil from there was fed under pressure to the filter and when it had finished passing through the filter element it was returned to the engine oil pan via the fitting in the upper passenger (right) side of the engine's cam gear timing cover. The reason the engineers placed that oil return fitting on that timing cover was to provide extra splash oil where it could help with better lubrication of the cam/crank timing gears.

The plumbing change you suggested above can be likened to connecting the natural gas supply line in one's home to one of the sink water drains. Not a very good idea and in many ways can be harmful and damaging.

jeeplvr247 · Post by **jeeplvr247** » Tue Jul 10, 2012 3:48 am

I will try to get some good pictures today after work. It is hard to get the stuff on the front of the engine because I have a big camera and there is not too much room in that area under the hood.

jeeplvr247 · Post by **jeeplvr247** » Wed Jul 11, 2012 3:15 pm

Ok, I finally got some picture lined up. Here we go:

For the first picture draw an imaginary line from the middle of the carb straight down. I have everything vent line to the right of this "line" but nothing to the left. I also have a fuel pump but no vacuum pump.

The second picture shows the oil line hooked up to the adapter (part E from the earlier post).

The third picture shows that same oil line entering on the front right of the engine, right behind the fan:

This just shows the whole drivers side of the engine:

And this is the bottom of the fuel pump and you can see the oil line and adapter(partE) from the bottom as well:

I am not sure why my pictures are posting so small, they are fine when I upload them. Hopefully you can zoom in and see them alright.

Post by **wesk** » Thu Jul 12, 2012 3:11 am

Now I see. That oil line attached to the front timing gear cover is the return oil line that connects to the bottom of the oil filter. Right now there is no pressure oil in that hose. I am assuming the prior owner then plugged the oil pressure line port hidden behind the fuel pump with an 1/8" pipe plug.

This illustrates where the upper oil line for the filter originates from. To install an oil filter on your engine you'll have to remove the fuel pump. Install the brass 90 deg. fitting and the new hose then put your fuel pump back on. Then disconnect that hose you have connected to the side valve cover vent fitting and connect it to the bottom fitting on the oil filter. I would suggest using a new replacement hose for that one.

Until you install a PCV valve that red hose will always have a slight pressure on it and will vent an oily mist.

Just install your PCV valve like this illustration. Ignore the tube from the fuel/vac pump. Just plug that side of the square brass "T" and install the tube that wraps around the front of the engine adjacent to your existing fuel supply tube to the intake manifold port under the carb.

jeeplvr247 · Post by **jeeplvr247** » Thu Jul 12, 2012 5:41 am

I do not know where I would be without you Wes, you are a saint among men. It appears that the mystery line plugged into the hole for the vent line under the carb leads to the windshield wiper (which dont work anyway right now so no biggie). For that PCV set up you showed in the picture I should just need a little bit of hose, the valve itself, a pipe plug, and the vent line right?
If I have this setup, does it work as well as original (except for fording of course) or should I try to get it back to original to be as good as I can be to the engine?

Post by **wesk** » Fri Jul 13, 2012 1:58 am

Yes, running a simple PCV valve circuit as I outlined will allow the engine to operate normally with no harm.

jeeplvr247 · Post by **jeeplvr247** » Fri Jul 13, 2012 4:07 am

Great. That is exactly what I am looking to do for not. Eventually I will get it back to original but the almighty dollar will dictate how long that will be. I am going to put in my part order this weekend and get everything taken care of.

Post by **wesk** » Fri Jul 13, 2012 9:01 am

Buy the PCV valve first. The inlets of the PCV valve will determine the starting thread sizes you need. Then take it to the hardware store to select fittings and hoses.

jeeplvr247 · Post by **jeeplvr247** » Sat Jul 21, 2012 5:38 am

I can only find the PCV through the specialty online stores. Can I use one from a CJ or should I stick with the military one?

Post by **wesk** » Sat Jul 21, 2012 9:29 am

Tech info and NSN info.

NAME VALVE,VACUUM BREAKING
PART_NBR 5336400
FSC 4820
NIIN 003607930
NSN 4820-00-360-7930
NSN 4820003607930

4820-00-360-7930 ( A0006895, A6895, GPW6769, 003607930, 4820003607930 ) NSN Information
NSN FSC NIIN Item Name INC HMIC ESDC CANCELLED NSN
4820-00-360-7930 4820 00-360-7930 VALVE, VACUUM BREAKING 08101 N

4820-00-360-7930 ( A0006895, A6895, GPW6769, 003607930, 4820003607930 ) Master Cross Reference Data
Mfg. Part Number ISC RNVC RNCC HCC MSDS SADC DAC
5336400 5 2 5
A0006895 9 5
A6895 5 2 3
GPW6769 5 2 5
GPW6769 5 9 5

4820-00-360-7930 ( A0006895, A6895, GPW6769, 003607930, 4820003607930 ) Characteristics Data
MRC Criteria Characteristic
AAQL BODY STYLE A1 STRAIGHT THRU
AAFZ BODY MATERIAL STEEL
AAJP OUTSIDE SURFACE TREATMENT BLACK OXIDE
ACSH SEAT MATERIAL STEEL
ADQU FLOW CONTROL DEVICE POPPET
ADQZ END CONNECTION QUANTITY 2
ACKM FIRST END CONNECTION TYPE THREADED INTERNAL PIPE
ACKN FIRST END STYLE DESIGNATOR G11 PLAIN
ACLG FIRST END NOMINAL PIPE SIZE ACCOMMODATED 0.250 INCHES
ACLL FIRST END THREAD DIRECTION RIGHT-HAND
ACLR SECOND END RELATIONSHIP WITH FIRST END NOT IDENTICAL
ACLS SECOND END CONNECTION TYPE THREADED EXTERNAL PIPE
ACLT SECOND END STYLE DESIGNATOR J6 PLAIN
ACMN SECOND END NOMINAL PIPE SIZE ACCOMMODATED 0.250 INCHES
ACMS SECOND END THREAD DIRECTION RIGHT-HAND
AEVX TEMP ADJUSTABILITY NOT ADJUSTABLE
ABJH TEMP RATING NOT RATED
AFLG ABSOLUTE PRESSURE SETTING 6.5
AFLH ABSOLUTE PRESSURE RANGE NOT RATED

This site shows one 5336400 in stock. Ask for an RFQ from them.
http://4820.iso-group.com/NSN/4820-00-360-7930

The early CJ's used the same valve under PN A6895