Ouch to you too. I saw the pic of your turbo. Sorry to see that.

 

Speaking of which, it is also possible to put the timing gear on the crank backwards, which can also cause problems.

 

Update:
Claus has been super generous and lent me his mechanical oil pressure gauge. The original gauge is working properly. I see 20psi of oil pressure at idle. If I put in THINNER oil I see higher oil pressure. It is not the crank pulley or P/S pulley. Not the OPRV. Not the oil cooler housing. Not the crank bolt torque. I think we have narrowed it down to the oil pickup.

After starting the car a few times after doing work to see if I fixed the problem.... I am worried that I did some damage to the bearings possibly? They were all new and I pulled the engine to reseal the crank girdle. When I looked at the bearings they all looked good and dull but the last main bearing showed some signs of bright silver colored wear on it. Is that the bearing just getting through the break in coating on the bearing? Either way, that was then. I have been running it more times since then trying different things. Considering I only have about 10-20psi of oil pressure at idle should I replace the bearings when I go in there? I know that means pulling the engine again but at this point I don't mind. I would rather have it fixed and run forever then have it fixed and have bearing problems 30k down the road. Suggestions?

 

The bearings are getting oil first. You should be okay at this point, but you still don't know what's causing it. Are you running the engine or cranking it over to check oil pressure?

 

I don't build pressure, according to my old gauge, if I just turn it over without running it. Sure the bearings get oil first but that doesn't mean much when there is only 10-20psi.

 

Update: Pickup is out and is not cracked. It can suck oil throw it no problem. So I guess that leaves the oil pump huh? Still doesn't make sense to me, the oil pump was fine in the last motor, sat for 3 months and then I ran it. Whatever.

 

Possible suggestions:

1. If the bearing to crank journal clearance is excessive or even too tight, the engine will not be able to build oil pressure. Did you plastigauge your bearings? From your description, sounds like there is an issue with the bearings. Never trust a machine shop, always double check critical clearances (crank/rods/cylinders/etc).

2. Possible block in the oil passage. Did you clean the block well? Install proper gaskets that did not cover an oil passage? I will only use Porsche OE factory gaskets, all others are junk.

 

blockage before the area you are measuring? that would explain higher pressure with thinner oil?

 

I have lower oil pressure after the car warms up. But...if I put in thicker weight oil I have LESS oil pressure. I'm so confused.

 

Any air leak before the oil pump will cause this.
The locktite on the oil pump is critical – some parts of this are on the suction side (won’t leak oil out – just air in). The thicker vs thinner oil really points to an air leak as a problem.

While it is not your problem the idea of the wobbly PS pulley is a good idea – I have seen quite a few PS pulleys with the tell tale crescent marks!

Chris White

 

Consider this theory:

The oil system is designed to have specific clearances in which to travel. These clearances are so important that the designers take into account the oil viscosity (thickness). This is why the factorys all recomend specific oil viscosity.

Oil follows a specific path in the engine. Starts in the pan, into the oil pick up, to the pump, into the bearings, through the block, into the head, back down into the pan. The oil pressure sender is somewhere in that path, but I am pretty sure it is after the oil goes through the crank. Point being, the pressure gauge only sees the oil pressure after the crank and not what is going on before the crank.

Now lets say your bearing clearances are too loose. This is easy to understand. Try blowing through a straw (small clearance), then through a 4" pipe (large clearance). You will not be able to build the same pressure that you get in the straw, as with the 4" pipe. This senario would cause your confusion, since thicker oil would take up some of the slack and effectivly reduce the clearances. Which in turn should increase pressure.

Ok now to your specific issues:

Lets address bearing clearances that are "too tight". What a tight clearance creates, is basicly a blockage in the oil passage. So if oil flow is restricted at the bearings, you should see a higher pressure before the blockage (bearings), and lower pressure after the blockage (to the oil pressure sender). The key here, is to remember the oil gauge will not see the high pressure at the possille bearing blockage, only the lower pressure after the possilbe blockage.

The comment that "thicker oil, reduces pressure" makes sence in this situation. The thicker the oil, the less it will be able to flow through the blockage, and thus the lower the pressure after the blockage.

You also noticed the bearings were scuffed. Further indication that the bearing clearances are too small. With clearances that are "too tight" the crank would ride on the bearing surface, instead of on a film of oil and thus "skuff".

Well you asked for any theory, and this one came to mind.

In the trouble shooting of mechanical issues, you always check the easy stuff first. Bad gauge, sender, wiring, oil, filter, etc. Then move on to the more difficult stuff, oil pump, pick up, bearing clearances. To the most difficult, dissasembly of the engine to look for gasket blocks to internal passage blocks.

If you are lucky, you will solve the issue on an easy item. And not have to take apart the complete engine to find that a wrong gasket was used at some point.

Then again if you were lucky or perhaps better yet "skilled", you would have assembled the engine with no issues at all. Good hunting!

 

A nice try - but the pressure sender is immediately after the relief valve and long before any bearings.

It’s the classic air leak on the suction side.

Chris White

 

When you re-sealed the girdle, did you confirm it was exactly flush with the block where the oil pump mounts and/or use an oil stone to get it flat? If not, a lip/step can prevent the oil pump from sealing.

 

Derek,

I agree completely with Chris and Tom. Your problem is an inadequate seal of the girdle to the block where the oil flows from the pickup to the pump or the pump is not sealed perfectly to the block. If you have confidence that the block/girdle seal is good then remove the pump and check the block/girdle face alignment, stone it if necessare and reseal the pump.

 

Great info guys, I really appreciate it. The only thing is that when I had the engine out last time, everything looked perfect. I put a good amount of locktite to seal the girlde, the girlde to block surface was flush and everything seemed sealed. I looked through everything very closely when I assembled it and anywhere that was even questionable if I had to seal it, I did. Although, I didn't question too many spots because it is a pretty simple layout.