dreygata

Also, is it possible that the washer that buts up against the drive gear needs to be replaced? I don't know if that is considered a wear item. I really don't want to undo the timing/balance shaft belt install that I paid for, but unless it's the pickup tube, it seems to be where I'm headed.

Coloradoguy

Hey there, dreygata. I just recently solved my no oil pressure problem on my 1986 944 so I sympathize. Mine turned out to be a stuck open OPRV.

If you've got no oil gushing out of either the OPRV or oil pressure sensor mount then the problem must be upstream from there. Since you state that you had a complete engine rebuild you might be suffering from a loss of prime from the oil pump. There are a lot of threads on this. What some have done is apply 10lbs of air pressure down the dipstick tube while pinching off the hose that goes from the oil filler to the intake manifold. Have an assistant crank the engine while doing this. Some have reported that this provides pressure within a few seconds.

I have no personal experience with this but it sure beats dropping the oil pan.

dreygata

I didn't try priming it when I cranked it over for the OPRV hole, but I have poured oil down the filter hole, which supposedly primes it. I've gotten around 1-1.5 bar at idle, and up to 4 bar when revving, so you'd think it'd be primed.
I might reinstall the OPRV and try the other priming method to see if it helps. I'm not super hopeful, but I suppose it's worth a shot.
At this rate, despite rebuilding the thing myself, I'm beginning to question whether or not I put various seals in. Probably mostly self doubt and anxiety, but I can't help but think something more internal is wrong.
I'd be happy if I just needed a new oil pickup tube. I really don't want to need a new pump.

Coloradoguy

Which hole did you pour the oil into in the filter mount? It's not the center one, which feeds the bearings. You're also supposed to turn the engine crank counter-clockwise while priming the pump in this way (something I wasn't very comfortable with).

And just to be sure, you said your car is a 924, not a 944?

I know it can be frustrating when you're in the middle of these seemingly insurmountable problems but sooner or later you WILL figure it out.

dreygata

I may have messed that up then..... I never turned it counter clockwise and I think I did the center hole (can't remember).
And it's an 87 924S which is the 924 body with the 944 2.5L N/A engine

dreygata

Dumb question. Is it possible that my issues are from a missing dipstick tube o ring? My car didn't have one when I removed it during the build, and I never could figure out one that seated properly so I installed it how I found it, sans o ring (I think).
Thoughts?

Coloradoguy

I'm no expert but that seems like grasping at straws. I couldn't see how a missing o-ring on the dipstick tube could affect oil pressure; the system isn't pressurized -- it's not like the engine can't run with the dipstick removed entirely.

There's a washer that goes on the crank that by friction turns the oil pump. I've read that this can be installed backwards and then the pump will not work. I'll see if I can find the relevant discussion.

https://rennlist.com/forums/924-931-...r-rebuild.html

This owner's problem was a missing seal on the oil pickup tube, but there is a brief discussion regarding the washer that activates the oil pump. This would be something you might want to check.

dreygata

That's possible, and honestly everything is at this point. Tried the oil in filter galleys, cranked backwards, air pressure, etc, no pressure building when cranking with DME out, under a bar when running.
i managed to get out to shoot out of the oprv hole with air pressure, so, that's something. My oprv threaded in almost entirely by hand, and the oprv seems to be operating smoothly, so I think the oil cooler housing is definitely ruled out.
I read somewhere that the clear Victor reinz oil pickup o ring gasket can be troublesome. I have that installed, but am contemplating getting an oem one.
I'm not sure about that thrust washer being backwards, but it warrants a look I suppose

Coloradoguy

Did oil gush out of the OPRV while cranking?

Does the engine SOUND like it's got no oil pressure when running? What I mean is, are you going off the dash gauge saying that you have no oil pressure or do you KNOW you've got no oil pressure?

I swear, this sounds so much what I just went through over the past month trying to suss out my oil pressure problem.

What brand of oil filter do you have?

dreygata

I can hear the lifter tap, so it does sound like it.
and my filter is an STP one from AutoZone. Would that be causing issues?

Coloradoguy

In the world of percentages I'd say your filter being the cause would be very, very small; but then again, it's a far easier switch than tearing into the oil pump. Couldn't hurt to eliminate it from the list of possible causes.

I'm currently running a K&N. When I had my trouble after an oil change, I called K&N and discussed my problem with them. They suggested I reinstalled my old filter just to see if by chance their filter was faulty. I told them I couldn't do that as I'd put a nail in the head of the old filter in order to drain the oil more completely (don't ask). They went ahead and mailed me a brand new filter free of charge anyway. Great customer service, that.

I've heard bad things about the Fram, but nothing about the STP. The main thing is that the filter should have an anti-drainback rubber dohicky that keeps the oil inside the filter, given its back-asswards orientation. Both the Mahle and the K&N have this. Others may as well.

Are you sure you installed the oil pickup tube seal ring?

https://www.ebay.com/i/312044122652?chn=ps

Not having this or having a poor one will provide the symptoms you're describing.

And a very nice oil pathway diagram here:

https://rennlist.com/forums/944-turb...-symptoms.html

dreygata

Hm. I know the filter had a spring in there, but I didn't look as to how it functioned exactly. From what I understand, the anti drainback just prevents the pump from losing it's prime. I think I'm just going through denial about dropping my oil pan, given the terribly length process, and/or getting to the drive gear, and wasting the money spent on getting the belts professionally installed.
Sigh. I'm not going tobe able to get to that stuff this weekend, so I may go ahead and order a new OEM pickup tube o-ring anyways before I tear into it. I sadly live in an HOA neighborhood, and while they really aren't all that bad about me working on my car in my driveway, I do try to appease them by making it look presentable (under a cover) and not being mid-project for a week.

dreygata

I'm beginning to lean towards my oil pick up tube seal being incorrect. I found this post (https://rennlist.com/forums/924-931-...tube-seal.html) that talked about how there were black, red, and clear version of the tube, but they weren't interchangeable. I fully trusted my victor reinz rebuild kit, even though I did have to order some replacement seals here and there for being an incorrect one for my exact engine. Given that, the seal is likely my issue as I THINK it's clear, though it's been so long since I installed it, and I didn't take pictures of that gasket. Looks like I have to drop my oil pan to really know

Coloradoguy

I understand the desire of the HOA to prevent a neighborhood from looking like the Beverly Hillbillies, but like anything else, it can be taken too far.

The anti-drainback simply keeps the oil in the filter from draining back into the block, thus speeding oil to the bearings upon startup. There has to be pressure to begin with for this entire process to work.

I'm sorry to hear that you're looking at a bit of work in order to sort out this oil pressure problem. Sometimes the learning curve on these cars is very steep. A simple thing like a misplaced o-ring can keep the entire thing from springing to life.

Just think how good it will feel when you turn the key and the gauge pings to 5, as it eventually will. Keep us posted.

dreygata

Ok, finally tore into the engine and removed my oil pan and pulled out my oil pickup tube and the return tube.

The clear gasket that I installed on the pickup tube looked fine and like it was sealing. I'll be replacing that with the black seal I got in from 944online. The tube also looks like it is intact with no cracks. I'll do a test where I fill it with water and look for leaks before reinstalling though.

However, it looks like I forgot to install the oil return seal. Could this have been the source of my woes?
I have a replacement also from 944online that I'll be installing, but wanted to see what the community thinks before I button it up.
It seems like the pump should still be able to "push" the oil without that seal, but it just wouldn't return in a pretty manner, unless returning the oil directly into the pump is critical to maintaining pressure.

If it's not that, then the only thing left is my oil pump/drive.