Is it the Carbon Muffler HKS exhaust?

 

its not a carbon muffler

 

well got the car buttoned up, the front half of it at least, dash forward and took it for a few rounds around the block, getting the driveability sorted, etc...well after the first drive or 2 after pulling back into the lot, i saw the oil light flicker. So i decided to put an OPG on it and the car has low pressure, 20psi on a cold start and about 10psi hot idle.

I just put some fresh 20w50 vr1 in it, the old oil had just idle time didn't see anything concerning and the car isn't making any sort of noise but something def isn't right. Maybe a bad pump, loose pickup or bad clearances...so the next step will be to pull the pan and take a look to see if something obvious is going on or not.

 

Old head here as well. Still have my original car but did get nostalgic and got back into a 1g as a daily and resto project.

Was it something obvious or did it end up being the pump?

 

Been busy with other projects, haven't had a chance to yank the pan yet.

After changing oil to 20w50, comp test and doing maintenance, it had no pcv setup and no catchcan so i hooked pcv back up, verified with 2 diff gauges but it seems like oil press even on a cold start doesn't get above 20+ psi according to my aem oil press gauge, mounted off my oil pump. Motor sounds fine, old oil looked fine, no obvious shavings or glitter.. hot idle is like 10-11ish psi. I"m thinking the best course of action would be to drop pan, check rods? faulty pump(unlikely im guessing) stuffed pickup? i drove the car probably like 10 miles in the process of making it in a driveable car. Once i verified with my OPG that pressure was too low i parked it.

 

anyway you can try a different senser or like a manual gauge to verify that that sensor is correct?

 

i did replace the oil pressure switch, the fact that its new and still makes the light come on at idle makes it clear that there is an issue. I did try a mechanical gauge as well previously. Also i mentioned i did a compression test after buying the car, it was a solid 165+ across the board. Just interesting that despite potential oiling issues, compression/oil rings seems to be fine.

 

So I did a few things, unfortunately still seeing the same issue.

Pulled the filter, cut it open. Looked fine. Keep in mind fresh oil and filter had only 12 miles on it.
Oil looked fine as well, some metallic shimmer but the engine looks brand new, i think its mostly from new break-in. Somoene mentioned balance shaft delete and bearings could be the culprit but they are still in place.
Dropped the pan, didn't see any bearing material. However it did look like the pickup at some point was touching the bottom of the pan. This seemed like the smoking gun, I could see the outline of the pickup on the pan. Straigntned the pan out, put some grease on the pickup to ensure it wasnt touching the bottom of the pan and it passed the test.

put it all back together, on a cold start with 15w40 it still showing me 20ish PSI of pressure. After it warmed up i gave it a few revs, 2k rpms gave me ~18 psi but 3k rpm holding the revs gave me like 23psi of pressure.

Leaving me with 2 places to go to next. Either a faulty aem oil pressure sensor or a bad potential pump? I guess the next time I yank the pan, ill check the rods and plastigage them to see what clearances are like. Open to ideas and suggestions.

 

If you haven't tried another gauge yet, that would be my next step. What you are seeing is pretty odd, the hot oil pressure isn't that different from what I'd expect but your cold pressure is far lower that I would expect.
To me, this doesn't point to a mechanical failure like a bearing, it points to some kind of either pickup or sensor issue. When you had the pan off, did you check the pickup o-ring?

 

Oh yeah it looked fine. The gasket was present. Didn't look like any fishy business. Even the oil that came out of the cooler looked clean. I had a mechanical gauge on it prior to switching to the aem but no harm in trying the mechanical gauge again.

 

Man that's pretty weird. I am really struggling to figure out how the cold pressure can show low like that without the hot pressure dropping off a lot more than it is. I mean the hot pressure is maybe a bit lower than normal but it doesn't seem to track with the cold pressure.

 

Not that this matters but where are you testing the pressure at?

 

I have the aem brass fitting mounted to where the oil pressure switch threads into at the rear of the block. I'm going to screw a mechanical gauge on the oil pressure housing, which is where I had it before when i previously tested with the mechanical gauge.

 

Yea use the oil filter housing instead of the oil pressure switch. They moved the oil pressure switch to the oil filter housing on the 9.

 

Cold start pressure shows about 30psi with 15w40 oil with fitting at OFH. Strange thing is with the car warmed up, with a steady idle the pressure fluctuates between 12-20psi...at this point im just gonna yank the motor and send it to the machine shop to get it clearanced and see what the mains look like. I was going to do it myself, but id rather not screw around and just get it done proper, if thats whats needed. Have a new pump on hand ill throw on when its all back together.

With that being said, are there any restrictors or anything of the sort in the head/block that regulate oil flow? I know on 6g72's theres restrictors in the head, that help to regulate pressure, just want to make sure with the big items being addressed(bearings/pump/clerances) I dont miss anything in the details.