4a84a standard military engine no oil pressure Help

[Dwnorton1]

I have drained oil dropped pan and cleaned check valve
opened and cleaned oil pump and verified tolerances.
Cleaned oil pressure regulator
blew out hoses.
Used air to blow oil back into pump thinking it might help with prime
everything appears normal except it will to pump oil.

What at am I missing?

 

[glcaines]

I have no experience with this engine, but have the following general suggestions.
1. Are you sure the intake to the pump isn't leaking and pulling in air?
2. Have you verified that the oil pump is actually turning?
3. How do you know that there isn't any oil pressure? Are you relying on a pressure gauge on the engine? If so, I would test the oil pressure with an external test gauge. It's possible the pressure sensor and/or gauge itself is faulty.
Good luck.

 

[Dwnorton1]

After tearing one of these apart and lookng at is oil system and not finding anything visibly wrong I was indeed perplexed. Oil pump is at rear of engine with a gallery down into the block to a check valve in the pan. If camshaft is turn and keyway is not damage oil pump will turn. I cleaned everything up put back together, my thought was check valve was not holding. Left oil line off to filter so I could see immediately if was pumping. Even primed the pump by forcing oil down line with squeeze bottle. Confident that I had isolated problems, I tried to run it again. Other than oil I primed it still didn't pick up.

So so I gave up on the 1969 model ( like me ). Nostalgia is why I want this gen set to run. Hokey I know.
Bought a new in crate from guy down road, had to pull starter off of my old one as this one had been robbed.

Pulled off oil oil line so I could see as soon as it made pressure. Tried it. Same thing. &$@&)((($7(() string of obscenities started and lasted for about 3 days.
Starter had started dragging from the 300 or so starts I had attempted, so back down road I went. We took another off another crated engine. It still had initial depreservation book with it that recommended the following:

Remove plugs as spin motor for 45 seconds let starter cool repeat. First thing I noticed was pure speed of new starter. New engine made oil pressure after about 30sec. Ugh. Yeah I put new starter on 69 model. Bam. Oil pressure.
Wow I had spent 2 days tearing a motor down for naught. Was good experience (bright side).
Just hope to prevent anyone else from this is why I'm documenting it here.

 

[Dwnorton1]

Pictures:make context of thread much more efficient. See I'm learning.


No i no I didn't get it put back together. Had invested to much time in already. Pushed back down priorities list to #2374.
Just another project that I will come back to someday. I really am going to complete one someday.

 

[glcaines]

Just another project that I will come back to someday. I really am going to complete one someday.

I have a lot of projects on a similar schedule!

 

[combat32]

Who has new in the crate 4a084 motors in oklahoma?

 

[Dwnorton1]

Who has new in the crate 4a084 motors in oklahoma?

There was old man down street from me that had couple and misc parts. I about wiped him out. The forest service in Goldsby has quite a few sitting out in rain because they don't have inside place to store. GSA takes a year or more to auction off. Sad Really. Use to be guarded by a wall of Goats, but no more.

 

[Guyfang]

The starter was probably the biggest PITA for this type gen set, 5KW or 10KW. Bar none. We always had several in a box, hidden, to keep us looking honest. Then came the Carburetor, followed by the Magneto. I suspect the Carb problems were mostly because we ran bad fuel. The mag was because we could not get repair parts, so we "borrowed" old magnetos, and tried to "fix" them by "controlled substitution". Because the starters and Magnetos were "repaired" by a maintenance company near by, and we occasionally donated a case of Schlangala beer to the guys, so we always had extras, but QA/QC was NOT good. The early 70's was not a good time to request parts!

 

[tommys2patrick]

the parts supply system in the army, particularly Germany, of the early 70's, always perplexed me. Units that were tasked to be 100% "ready" on all equipment/vehicles were limited on how many parts they could have on hand. usually the ones that were make or break to getting something working right. I had to keep a stock of mission critical parts on a deuce driving around the base while the IG was in town. We had a pretty good midnight auto supply business going between Mannheim and K Town.

I have a couple of those gennies. when they run they seem to just keep plugging along. Kind of wish they had a kick starter like a motorcycle. Of course it would probably launch you higher than the first Sargents right boot.

I have a number of new engines in the crate. I think they are the smaller flat fours. will have to double check them when the snow melts a bit around here.

 

[Guyfang]

We kept the same type of "rolling stock" when the IG came to town. We could have been business partners!

The maint unit used a large impact gun to start gen sets with dead batters. Worked great. Just had to be careful with it.

In June 2010, I found several of the 20HP engines in an SSA in Schweinfurt. Crates looked new. The SSA Warrant told me he had a customer that requested one every so often. I would maybe guess a M10 DECON rig, or some sort of Tank and Pump Unit. He had carburetors and starters also. Surprised me all to death. The last time I worked on one was mabe 1974-75?

Where were you at? What unit? I was in C-3/7, ADA, Bamberg.

 

[tommys2patrick]

Pirmasens, Army Air Base, 1971-73. I got to be pretty good at finding back doors to military warehouses for those "Gotta Haves". Getting off topic but I can remember finding old german WWII parts in some of those warehouses. Some of the warehouses were run by german contractors that also supplied the local militia/police units. They were still using some really old stuff, from both sides of the big pond.

 

[Dwnorton1]

For posterity on lack of oil pressure. My professional opinion which is not professional but is indeed my opinion is as follows:
1. Remove spark plugs
2. Spin motor for 30-40 seconds. To blow out preservation. Let starter cool repeat(should be pumping oil on this try if not already.


That was in a nutshell what manual said. Here is my opinion part. The removal of plugs is two fold. I believe starters on these would have trouble ever spinning motor fast enough under compression to get oil pumping after motor has been sitting anywhere from 1-25 years. This is what I experienced anyway. The original starter I had just wouldn't spin it fast enough and without removing plugs even the new one might not have been able to get the oil flowing.
If you are reading this because you are having same problem try above steps. I believe in documenting troubleshooting items like these because the wealth of knowledge found within this forum from the gentlemen that actually had to make this equipment work needs to be captured so we don't have to re-learn that they they already experienced. That knowledge base won't be around forever.

 

[glcaines]

I'll throw my in as well. I would recommend adding some oil to each cylinder to provide some initial lubrication to the cylinder walls prior to spinning the engine sans the spark plugs. I always do this with any engine that has been sitting for an extended period of time without being run.

 

[Dwnorton1]

Very good point. I did that as well. I also used a squeeze bottle to force oil into top end of motor. Just freaks me out to think I am going to cause metal on metal contact for 45seconds until I can build oil pressure on something that hasn't seen oil since Carter was president. Lol. With their external filter you can remove line and force oil into motor not the case will all but with these doable.

 

[DieselAddict]

One of the things we would do on engines that hadn't started in a while was to pull the oil pump and about half pack it with light grease. That would get them to suck the oil up quickly. This was a pretty easy job on american engines where the oil pump was driven from the distributor.

Yea, Whats a distributor..

 

[Dwnorton1]

Thanks, I had not thought of that. The worst part of oil pump on these is that the flywheel has to be pulled to access oil pump. I have one that is still broken down that I am going to use this trick on.

Distributors kinda of went the way of the dodo. Were everywhere and now if you see one you do doubletake.

 

[Guyfang]

Very good point. I did that as well. I also used a squeeze bottle to force oil into top end of motor. Just freaks me out to think I am going to cause metal on metal contact for 45seconds until I can build oil pressure on something that hasn't seen oil since Carter was president. Lol. With their external filter you can remove line and force oil into motor not the case will all but with these doable.

I believe Mr Nixon or Ford was the prez, the last time I fooled with one of these engines.

 

[Dwnorton1]

Now you are showing your age. Not saying you are long in the tooth...... I just say very experienced.