My 95 z28 when I first start it has perfect oil pressure then When I warms up and I take it around the block all the sudden the oil pressure just Drop. I just changed the oil and oil sending unit. Also when I shut it off the car will not start again but after I let it cool down It starts right up. I think the alternator might be bad and charging to much. Could that be the problem?

 

My friend has almost the same problem in his formula. When it is cold, it runs 40-50lbs, when it warms up it run's 10 lbs constantly. We think it my be a spun crank bearing.

 

I spun a bearing not long ago and that's what mine did. The pressure would be alright until it warmed up and it would drop almost to nothing. I replaced the bearing and polished the crank and the pressure now sits at the midway point (higher than it ever was before) but once it gets warmed up it goes to the 1/4 mark like it was before I spun the bearing.

 

Why would the oil press drop because of a crank bearing though it doesnt make sense to me and would it run like garbage if i spun a bearing my car does run to bad

 

If the bearing has been spun the clearance between the crank journal and the bearing will be larger, allowing the oil to leak out and thereby decrease the pressure.
And yea, it will make the car run bad. If feels just like you would expect it to if there was more friction on all the moving parts. My car also doesn't want to start when it gets hot but starts fine when it's cold. Try pushing the pedal halfway down before you crank it, that's what I do and it always starts with that method.

 

My car doesnt even turn over when its hot. Its like my battery is dead or sumthin but its not. Also my car sounds good when i rev it would it be knocking or sumthin if i spun a bearing?

 

Heres something to think about:

If the starter doesn't spin when hot, it could be that. My starter wouldn't spin unless it was being jumped when it was hot. Cold it would spin fine. Turns out that the exhaust manifold was heating up the starter solenoid, and when my friend tapped it, it would start without having to be jumped.

About the oil pressure, I have no clue. Mines at 60 psi(3rd tick up from red) cold(idle) and 20-25(1st tick up from red) fully up to temp at idle, driving around(1500-2000 rpms) its about at the middle tick mark. WOT is 80 psi.