No oil pressure!

evilmiata · 10-20-2008, 09:44 PM

I've checked the oil pressure with two sets of gauges and still can't get a signal. There is plenty of oil flow, just no pressure. The motor has run for ~20 minutes. I pulled the motor and removed the intake manifolds. The camshaft is still mirror smooth and the rocker arms still have assembly lube on them.

I suspect that I installed a main bearing incorrectly. Is there a way to quickly identify the culprit?
Is there a way to test oil pressure that doesn't require reinstalling the oil pan?
What else should I check to make sure that I'm not losing oil pressure?

Superdave · 10-20-2008, 10:28 PM

Drop the pan, don't run it anymore.

make sure the pickup didn't fall off the pump, also make sure you put the pump driveshaft in.

evilmiata · 10-20-2008, 11:05 PM

Quote:

Originally Posted by Superdave

Drop the pan, don't run it anymore.

make sure the pickup didn't fall off the pump, also make sure you put the pump driveshaft in.

The pump isn't the problem. There is plently of oil flow, just no pressure.

The_Raven · 10-21-2008, 09:00 AM

If you're sure that there is actually oil flowing (I'd test by removing the OPSU and priming the engine to see if any oil comes out of the OPSU port), then remove your front cover and your timing chain set, I bet there's a missing plug for one of the oil galleys.

I also bet you'll need to tear the engine down, running for 20 minutes with no oil has probably damaged some of the bearing surfaces. If it's a genI or II, then I'd pretty much guarantee that the main and rods bearings will be toast since you say there is no oil on the cam, and these two generations use "Cam priority oiling". If it's a genIII you may get away with not replacing the main and rod bearings because there's a chance that the oil may have been able to get to the crank, due to the "Crank priority oiling" that is used by the genIII. Either way I'd be very surprised if the cam bearings haven't spun, which will require a new block, or at very least lots of machine work and oversized cam bearings. 20 minutes is about 19 minutes longer than needed to cause damage on a fresh rebuild. Assembly lube can only prtect so much.

evilmiata · 10-22-2008, 12:03 AM

Thanks for the heads up, Raven. I did confirm that there is oil flow by spinning the pump with a drill and removing one of the lines to my remote oil filter. I'll start the teardown soon and keep you guys updated.

evilmiata · 10-23-2008, 12:11 AM

I removed the oil pan and found a ton of thick, gloppy stuff at the bottom. I couldn't tell if it was filings or just 5-year-old sludge. I pulled the first main bearing and it looked ok. Then I removed the cam shaft and found this. Opinions?

evilmiata · 10-25-2008, 12:20 AM

No comments? Does this cam shaft look worn?

betterthanyou · 10-25-2008, 08:21 PM

Is that rust? How long was this engine sitting for? Do you have any clues as to the pressure problem.

Superdave · 10-25-2008, 09:57 PM

if that cam is new then i'd have the bearing surfaces checked and polished at a machine shop. If it's old then it's probably fine. the wear on the lobes looks like typical flat tappet wear to me... the rust is weird though (if that's what it is).

How do the cam bearings look? Lifters?

evilmiata · 10-26-2008, 07:35 PM

I did notice a small surface stain on the camshaft in the first picture. The orange bit in the following pictures is a bit of RTV sealant from the disassembly. I've had the motor for 5 years and bought it as a GM crate engine. It sat untouched for almost 2 years. I thought maybe I messed up reassembling the bottom end when I upgraded with gapless piston rings and ARP hardware. However, this is the first time I've removed the cam shaft.

I'll update you guys on the cam shaft bearings if/when I pull them next weekend.