New engine, no oil pressure

I bought a reman'd '74 304 for my CJ5. I installed my old instake, carb,ect. While the engine was still on the engine stand and prior to installing the valve covers and distributor I borrowed a oil pressure guage and oil pressure priming tool. I pre pressurized the engine until I saw oil coming out of all the push rods and the guage read over 90psi. I used a 1/2 in drill and it made it grown. After installing the engine and adjusting the timming, it started right up, but I noticed my oil pressure guage wasn't moving. Today I dropped the oil pan to make sure the pick-up tube was ok, and everything looked good. I pulled the distributor and tried to manually prime the engine again, but It didnt help. It was like their was no resistance. I used a 1/2 in cordless drill and their was no resistane on the drill this time. Am I missing somthing simple. Sorry this is so long I just wanted to let you know what I have done so far.

 

WoW ! I'm thinking change the oil pump ,,. It is a reman'd and something let go of the ghost
!

 

This engine was rebuild by a very reputable company. Thing is it had oil pressure on the engine stand, now it doesn't. From the manual I have their isn't much to the oil pump, just a couple of gears driven by the distributor. What can really go bad there? The manual says to fill the pump with petroleum jelly prior to installing the cover. I can try that next, but like I said it did have pressure on the stand. Help!

 

Considering the design, it's hard to imagine the oil pump gears not spinning if you are turning the distributor drive. The distributor shaft sits down in the shaft connected to the oil pump gears ... not much to come loose or break.

Here's the oil pump gears (courtesy of BullTear):



Your drill should be turning the slot in the top of the shaft. Not much to go wrong between there and the oil pump.

It's possible that the oil pressure relief valve in the oil pump cover is stuck open, and you are dumping the pumped oil back into the pan... or maybe there's air getting in somewhere between the pan and the gears, like a crack in the pickup tube. Pretty sure the pickup tube goes right into a passage in the block, which feeds to a passage in the timing cover and into the pump gears. Again, not much to go wrong.

 

What oil filter are you using?
There were a few people on bulltear with the same problem. Has something to do with the anti-drainback valve, some oilfilters don't have them, and the oil can drain back to the pan or something like that. I would go to bulltear.com and search

 

The Fram Tough Gaurd has the valve. Don't use them on a Ford or AMC. Maybe it lost prime. Or pick up cracked like Tim said. Was it packed with Vaseline? Oil pump on AMC v8 should be for first startup. Nothing to the pump, 2 gears, a spring and a plunger. Take the oil filter off, remove the 6 bolts and the pump comes off and the gears will slide out of the timing cover. Spring and plunger are behind what looks like a 3/4 inch hex plug. You took it to 90 psi it might have broken or stuck the spring (bypass valve). make sure it is not stuck/broke, repack gears (and I mean pack) put it back together and spin it again, just not as high psi.
Were you using the same gauge when you ran it as you did to prime?

 

When I was reading this thread, I was thinking, maybe something is wrong with your dash oil gauge. Maybe a crimped line or if it is electric going to an sending unit, maybe just a bad ground or something. No I am not an expert on oil pressure issues. However, I have had my share of problems with gauges going south on me. You might consider rigging up another external oil gauge directly on your motor, and see what it does when you turn it over.

 

He said he tried the drill again and there was no resistance, so I would rule out the gauge.
I would not use a fram filter on any engine myself, but an amc filter needs to have the anti-drainback valve. I have found that the wix or Napa gold work very well.

 

I'm going to pack the pump with Vaseline tonight and give that a try. I did use a NAPA filter, but not a GOLD. I have to pick up some more oil today, I will ask them if my filter has a anti-drian back valve. That may be the trouble. It is a different guage then the one I used on the engine stand, but it is good. I can tell their is no oil pressure because their is no resistance on the drill when trying to prime the pump. I did pull the pump apart and the gears are turning, also I cleaned the pressure relief valve, it seems to be ok. Thanks for all your help Guys.

 

I have used Fram for 2 years with no problem, When I start a newly rebuilt motor I use a mechanical gage attached at the sending unit port. I do this so I can confirm oil pressure right away and I can see it when the engine fires.

 

Thats what I did when it was on the engine stand and it worked well. The guage on the dash has always worked good prior to the new engine. I think it's just a priming issue (I hope) from the info I got here. I let you all know how I make out.

 

Is it not possible to cut and paste photos? I was going to post some pics of my progress, but I can't seem to paste anything.

 

The older oil filter adapters had a bypass valve built in, as the newer ones do not. If you have the old adapter and the valve is missing or damaged/stuck, it would let the oil drain back into the engine and the pump will not pick it up. I would pack the gears to get the oil back up, run it to break it in (watching oil pressure carefully), then shut it down for a day. If there is no oil pressure after it sits for a day, then you have some problems with the bypass valves.

 

Why? Filter attaches to bottom of the pump on a v8 almost verticle, where is the oil going to go. With or without a valve, it will always stay nearly full. The valves stick on occasion and usually do more damage than good. Valves in oil filters is something that has just recently occured. They didn't have them when AMC started making/selling v8's, let alone GM Ford or Chrysler.

Not trying to be a smart*@@, but just wondered why an "AMC needs" a valve in the filter.

 

Amc filters are not vertical. It has something to do with the syphon affect, and the pump being so far away from the pickup. If it loses the oil in the pump cavity, it can't pick it up again. The old filter adapter had a valve built in, the newer ones do not, so the filter must have it. These are things I have learned from reading threads at bulltear.com. If I was going to trust anything anybody says about an Amc V8, it would be those guys.

 

The Vaseoline in the oil pump was the fix and the oil filter does have the valve. I stuck the distributor back in and it fired right up. I watched the guage as it went to 60 then 70 then 80 and before I could shut in down it was at 100psi and then I heard it. It blew the rubber seal on the oil filter and oil was everywhere. So here we go again, off with the pump cover and check out the relief valve. I guess thats all it could be, right? Can I post pics by "cut and paste", I don't want to do the photobucket thing.

 

No help with the oil pressure problem, but when you select new reply and type in your message you have to opportunity at the bottom to add/upload images. Keep in mind they have to be a certain size though. Do a search and you will find many a question on pics come up. Try it out in the test forum first if you need to. Good luck!

 

I had a similar problem on my 232. When I first got it home, after I cleaned it up, I went to fire it up for the first time, and BAM, blew the seal on the Filter and immediately dumped all the oil on the ground.
It was a stuck bypass valve in my oil pump. I replaced the pump (integrated valve) and that fixed the problem.
I realize they are different engines, but maybe that helps.
Good Luck.

http://www.earlycj5.com/forums/showthread.php?t=30285

 

I think I may have found the problem. I don't remember seeing this hole in the new gasket I got from NAPA yesterday. I think this would restrict the oil flow.
http://i725.photobucket.com/albums/ww259/79jeep_bucket/jeep2.jpg
http://i725.photobucket.com/albums/ww259/79jeep_bucket/jeep3.jpg

Oil everywhere. Thanks God for speedy dry.
http://i725.photobucket.com/albums/ww259/79jeep_bucket/jeep1.jpg

My Plum Jeep.
http://i725.photobucket.com/albums/ww259/79jeep_bucket/jeep4.jpg

 

The pressure of a positive displacement pump is determined by the head it needs to overcome. In a combustion engine adjustment of discharge pressure is accomplished by spring tension on a check ball. Sounds like you got a stuck check ball. Before I went any further I would pull the spring and ball and make sure it is working properly. It is usually a hex head cap just above the filter on the pump housing.:v6: