Oil Pressure Question on an SR20

[maxhopper]

Tonight I ran an oil pressure test on my 93 G20 (164k miles - driven all of 10 miles since purchased). The oil light was flickering on and off last week, I started the car saturday, and the oil light stayed on - I let it run for a few minutes, and turned the car off. I borrowed a gauge and hooked it up to the oil pressure switch inlet. According to the FSM, at idle the oil pressure should be 11psi, and 46 - 57psi at 3200rpm. After the car warmed up, the pressure was steady at 8psi. When revving the motor, the oil pressure would build to 10 - 11psi then drop to 5 - 6psi. When I let off the throttle, the oil pressure would drop to around 4psi then build back up to 8psi. I removed the oil fill cap, and saw that there was some oil getting to the cams. I have never had experience with a bad oil pump, does this sound like the problem? Would a compression test tell me anything that could be related to this? Is there anything else I can test/check?Thanks,Scott

Edit: Maybe this should be moved to Nissan Online Mechanic? I feel like Infiniti's bastard child.

[DAEDALUS]

Not good at all. Basics first--make sure the oil level is correct. Oil pump is one possibility, but so is worn bearings. Also, the pick-up in the pan could be blocked by something. None of these things will show up in a compression test. A worn bearing might show up in an oil analysis. No knocking in the engine?

[maxhopper]

No knocking, a little chatter in the top end - usually at start up.

[Q45tech]

Bearing wear, lots of bearings .........usual problem is the mains, cams and cam bearing bores.............lack of 90 day oil changes with a small sump capacity........highly stressed 4 cylinder..........usual last to 250k with excellant maintenance.........know one manual with 450,000 miles second engine/transmission. Perfect commuter car if you change all fluids regularly.

[Q45tech]

Change oil and filter after warm up should be 11-14 psi at hot idle with new oil.........you may need to go thicker 10w-40 with some BG oil additive, a splash of RD-7 to thicken the hot oil.

[Q451990]

Wasn't there a problem with the drain tubes that take oil back down from the cams and rockers to the oil pan sludging up? If I remember correctly there was a countermeasure part for this issue - but I don't know for sure.

Heath

[Q45tech]

Auxillary spray tubes to lubricate cam lobes ------plugged up and starved cam surfaces and rocker arms...............noise, sweeks, bad idle...........retrofit tubes with larger holes and change both cams and rockers was the fix.............temporary as damages were done easier to replace with newish JDM engine.

[maxhopper]

Thanks for all the great input.