SWEET98SS

iTrader: (8)

I havent taken the bottom end apart, cam bearings dont look that bad, cant really see them in there either. Yeah, I was pretty stunned when I saw it. It ran great except for the low oil pressure at high rpm, like 6800. Good thing I pulled the motor.

lmt0705

iTrader: (7)

How were mains?

SWEET98SS

iTrader: (8)

I havent taken the bottom end apart, the motor is actually still sitting in the kmember. once I get a stand, I will pull the bottom apart. This is going to be a winter long project as it wasnt expected.

why87

very interesting, wasn't expecting you to find that.

OldCobraGuy

iTrader: (2)

And I'm still not convinced that is the issue with the high rpm oil pressure drop.

1999transamls1

iTrader: (5)

bumping an old thread, but sounds like its doing exactly what mine is doing. sometimes when going WOT it goes from ~60 psi at 4500 rpm to about 40 at 6000, doesnt always do this when going WOT. im really confused on what to do, also when driving around it will occasionally drop when giving it some gas, then return as soon as i let off. so am i fu*ked?

SWEET98SS

iTrader: (8)

Is it low on oil?

1999transamls1

iTrader: (5)

nope, its a little over the x's

01ssreda4

iTrader: (96)

Thrust bearing....

1999transamls1

iTrader: (5)

guess ill check that today, sounds like im f*&ked

1999transamls1

iTrader: (5)

drained the oil and didnt see any metal flakes anywhere in it, and looks soild black with just just a little hint of marbling. also noticed that my oil filter wasnt tight all the way, i was able to take it off with just my oilly hand. is it possible that the oil filter being loose was the problem all along?

ZeeOSix

Doubt it was the oil filter unless it was leaking like crazy to cause low oil pressure ... was there oil all over the place by the oil filter mount? If not, then it's not the oil filter.

1999transamls1

iTrader: (5)

just replaced it and still does it, at 5k rpm its at 65 psi, 6k rpm its at like 40 wtf....

its not low on oil, so i have no idea what to do, tear it apart? put manual gauge on it?

HoLLo

iTrader: (17)

I didn't read the 4 pages, BUT I do know that cheap non-GM oil PSI sensors act a little off.. I once broke my oil psi sensor when putting my intake manifold on, and used a cheap Autozone brand sensor, and my pressure was immediately off. I never had an issue with dropping oil pressure before, but after this cheap sensor, my gauge would drop at WOT. I replaced it with the same brand sensor, thinking it was bad, and the problem is still there. I've been TOLD that anything non GM reads funky. I have not since replaced it with a GM sensor, but i find it funny that I never had any pressure drops until that cheap sensor.

1999transamls1

iTrader: (5)

Mines a gm opsu, i just replaced it.but I didn't torque it down, I just snugged it down.

joecar

The other possibility is a cam bearing walking.

1999transamls1

iTrader: (5)

Would any of those make noise? My car doesn't make any really besides an exhaust leak

01ssreda4

iTrader: (96)

Measure crank endplay. Takes 5 minutes or less.

1999transamls1

iTrader: (5)

i dont have a feeler gauge, but when i just checked the endplay, you couldnt even hardly see it move at all, you could just barely see it moving a tad. gonna have a manual gauge put on monday because i just noticed that it jumps around alot all of the sudden also. kinda leaning towards gauge/opsu/opsu harness

s346k

iTrader: (4)

any way you can install a mechanical guage on it before doing anything else? that would tell you the whole truth and nothing but the truth.

my 99 car never has made great oil pressure (according to the factory guage), but it has never had a problem building/holding it. it has pretty much been the same over the past 7 years and 80 thousand miles i've put on it. it hasn't had a hard life persay, but i can def attest to it not being an easy one.