Very strange oil issue

[79cj7duner]

First off, engine is a fresh 304 that I built 6 years ago. It sat in the garage for 4 years after I wrecked my first CJ. I wound up putting the whole Jeep back together last year and it ran perfectly and always carried good oil pressure. Then, in march of this year I went to get it out of storage and it wouldnt start. Come to find out I bought a cheapo timing set and it wasnt oiling things correctly. Got the good double roller set with correct oiling (cant remember name of it right now) New dist. gears from MSD (bronze one on dizzy) and she fired right up and has been running like a champ. Now last week I start it cold it has 65 psi oil pressure. Soon as I pull out into traffic it goes to 20 psi and stays there. Doesnt matter if you are at 600 rpm or 2500, or whatever, just stays there. Never used to do that, would hold 50 psi at cruise. Sometimes it seems like if you let off the throttle and coast it will gain maybe 2-3 psi, but falls right back when under power. When I put the new timing set and gears on I also put a new timing cover on and the later style oil pump cover with no bypass spring/cavity. So this weekend I pulled the pump back out of it, and the gears are showing some pitting on the edges of the teeth but nothing too serious. Pulled the oil pan off thinking maybe the pickup was clogged, but didnt see anything there either. Before I go putting rod and main bearings in it, is there anything else I should check as to why it wont hold oil pressure?

[tufcj]

My guess would be the relief valve is gummed up from sitting or you have a bad oil filter. The relief valve is under the large nut on the side of the oil filter housing. There's a spring and a plunger. The plunger should slide right out. Pull it and clean it and the passage with brake cleaner of something similar. It goes in point first. Use a good filter, I prefer WIX or Napa Gold. Fram has caused problems for a lot of people.

Bob
tufcj

[jeepsr4ever]

I think Bob is right you should take the 7/8 nut off the side of the oil filter adaptor and remove the spring and plunger. If the plunger is stuck you will need to push it back from the filter side. Clean the assembly and re-install.

[79cj7duner]

I did pull the plunger out before I pulled the pan. If it was stuck anywhere, it was stuck in the closed position, which I would assume would drive the pressure to the high side. It has a few scratches in it, but like the pump gears, nothing serious. I cleaned it up and it does slide freely in the bore now, just like when I put it in new, but had to tap it on the bench pretty good to get it out. I just assumed that was from the oil that was left in there holding suction. I always use wix or napa gold on everything I own. Now I guess I need to decide wether to look at some bearings or not before I put it back together and see if cleaning the plunger helped. If memory serves I would see damage on rear most mains first, correct?

[jeepsr4ever]

The rear 4 rod bearings is where you will se the first damage.

[79cj7duner]

Havent had a chance to pull the bearing caps off yet to look but had another thought. I have been running valvoline 20w50 conventional oil. Is that too heavy and possibly damaged the spring that holds the plunger in place?
I can get my hands on some John Deere plus 50 in 10w30 if that would be a better choice.

[Rich H]

Hi 79CJ, I am new to BuLLtear and I just wanted to say that I had the same symtoms that you are having and while I was ed with it all I changed the oil pressure gauge and to my surprise that was the problem.I hop it is as simple as that for you.

[tufcj]

20W50 shouldn't be a problem. I ran it in my 360 CJ for years. I have seen the relief springs weaken with age, they're easy to replace, and are included with the better pump kits on the market. Have you tried a temporary mechanical gauge, like said above? The senders and gauges do fail. Last thing I can think of is there should be a plastic "button" about 1/4" thick on the bottom of the oil pickup in the pan. It keeps the pickup from being sucked against the bottom of the pan. I usually braze a 1/4" nut to the pickup, since the plastic part isn't available anymore.

Bob
tufcj

[79cj7duner]

Gauge is a mechanical auto meter. I have complete faith in it, but I did check it with another gauge and got the same readings.

Bob, I think you are onto something with the plastic missing, because it is definitely not there!! There also looks to be something inside the oil pickup but I can't figure out what it is. Can you take the lower part of the pickup apart by prying the outer "lip" open? If not I'll start with a new pickup and put a nut on the bottom of it like you suggested.

[tufcj]

It's probably easier to just replace. Last time I looked, they were available aftermarket and weren't too expensive. I've also seen the pickup tube stress crack up near the threads. Once they crack, they suck air and can give some strange oil pressure readings.

Bob
tifcj