Low oil pressure after engine reseal 964

[smokintr6]

So, I just completed my first 911 engine reseal and I have an oil pressure issue. Not what I was hoping for obviously. Before we start I don't have much history on this engine. I bought it off of a guy on ebay about 4 years ago, it was supposed to be a drop in and go situation, but I foundon't a brokenew head stud and some other small issues, so down she came. Everything inside was outstandingly clean, and the main bearings were perfect so they stayed. Decided to put OEM porsche rod bearings in it and ARP rod bolts + head studs. New IMS bearings, and the heads were rebuilt, but everything else was reused.

Oil pressure came up on the starter, but only 1 bar which I thought was strange. I figured it would be much higher when started, but it only came up to 2.5 bar cold idle. It has no trouble getting 2.5 bar at a warm fast idle, but that's about all it will build. Im not driving the car while the issue persists, and I probably haven't revved it over 3000 on a quick blip. No change in pressure. I'm leaning towards one of the relief valves sticking or being installer wrong. I also have not yet checked with a mechanical gauge to verify.. . Any ideas?

Good news is, it runs nice and smooth, and doesn't seem to leak! Basically the opposite results of what I was expecting

[fanaudical]

Did you split the case on your reseal? (Am assuming so from the description above but not certain...)

Did you inspect the oil pump? Oil pump seals in place correctly? Piston squirters stuck open? Wrong restrictors in the oil lines to the cams?

Definitely start with a mechanical gauge. Also, make sure the pressure sending unit output matches what your gauge expects (there were a few changes over the years).

[smokintr6]

I did split the cases, and I did "look at" the oil pump, but I didn't tear it down. It spun freely, and there was no apparent damage to the gears when looking through the ports. I did install all new seals between the case halves... I believe there are three for the pump and one more between the case halves. It is a mid year car with a 3.6 swap, but the car has 964 gauges, and I reused the sending unit that came with this 964 engine, but you're right I need to double check

[smokintr6]

I didn't notice anything out of the ordinary with the squirters, and the 964 has those plastic bridges for the cam oiling... I'm not sure if there are restrictiors, or where they should have been

[boyt911sc]

Try to install a mechanical pressure gauge to eliminate any problem with the oil pressure sender and the dash pressure gauge. Second, test the oil pressure switch with a timing light. The TL should turn off when you crank the engine. Do you have oil restrictor at the cam tower oil line?

Tony

[fred cook]

I would bet that you cut one of the oil pump seals while reassembling the case. Been there, done that!

[smokintr6]

Alright, I get to close this one out, thankfully.... It turned out to be a gauge problem, or more accurately I don't think the sender is right for my dash. Hooked up a mechanical gauge and everything is as it should be!

As a side note a couple other things I learned in this process:

1. It doesnt seem like there are cam restrictors for the 964 engine. The oiling pipes from the chain box are already smaller than the earlier engines.

2. after looking at PET on Porsche's website I concluded that the late 944 and the 964 both use the same 928 sender. That means that the trouble shooting information from clarks garage can be used to check the sending unit.

[smokintr6]

Fred, how did you not push the car off a cliff after that discovery?

[fred cook]

Originally Posted by smokintr6

Fred, how did you not push the car off a cliff after that discovery?

Actually, it wasn't that bad. At that point, everything was clean and all the fasteners were new so they were not stripped or broken or whatever. However, when I put the case back together, I used my engine hoist to carefully and slowly lower the engine half into place rather than relying on arm and back muscles! I guess everything went ok the 3rd time (I had completely assembled the engine one time as a mock up to make sure I had everything the way I wanted it.). Now, 4 years later, the engine is just as clean as the day it was built!

[Catorce]

The starter alone is incapable of building significant oil pressure on a fresh motor. If you get a bar, you start the car. There, I trademarked that.

The spec is 1 bar per 1000 rpm. Sounds like you got that, and its fine.