twistedbowtie

i have a 95 z28 6 speed. rebuilt motor less than 10 miles. i have the cc306 cam. when at idel (750ish rpm)the car has only around 5 psi , but at 1200 rpm it has 16-22 psi. does this sound right ? i feel like its realy low. ive replaced the oil pressure sensor or whatever the correct name for it is. not sure if im missing something. oh almost forgot it has 10-30 oil. thanks guys
Dustyn

green.Z

There is a ball that is force fit in the oil passageway where the oil pressure sending unit goes in. It can be removed from the top and installs from the bottom. Is it possible this was left out? I've heard this can cause low oil pressure.

twistedbowtie

yea man thats a good possibility, i dont remember any kind of force ball. do you have a idea where i can find a diagram of that? ima check shbox but i dont think i saw it before thanks , dustyn

raroz28

There are a few reasons.

The main cause of low oil pressure is a spun rod bearing.

I have heard of some guys' oil pickup tube coming loose from the oil pump resulting in a drop in pressure. Sometimes it falls all the way out. If it has come all the way out, a few taps on the oil pan with a rubber mallet may result in a bouncing sound (pan has to be empty obviously).

The nylon shaft seal that goes on the oil pump around the shaft that goes up into the intake is very weak and can snap, which can result in low oil pressure. I have no experience of this, but I was told that it can result in a loss in oil pressure.

It's probably not a sensor, but to rule that out you can just install a mechanical oil pressure gauge.

You said the motor has 10 miles on it... If it was just rebuilt, did you make sure the bearing clearances were in spec.?

That oil pressure is way too low.

twistedbowtie

i agree way to low. i realy dont feel that it would be a spun rod all that was done by the book. the oil pump drive and all is brand new. have you ever heard of the ball in the oil pressure sending unit? i might have forgot that. i just am not to sure where it goes or where to find a new lol ? thanks

raroz28

No I have no experience with that. I have seen many guys who rebuild and have low oil pressure shortly after because their bearing clearances weren't correct or something was overlooked and not done properly.

I would hope that whatever your problem is it does not require another overhaul. Install a mechanical gauge to rule out any sensor issues and go from there. If the pressure is normal on a mech. gauge, then you can start looking into sensors.

If it's low on the mech. gauge, there is a problem with the oil pump, oil level or the bearing clearances.

SC/TA

Yes there is a ball that goes under the rear main cap. Some people use a small freeze plug instead of the ball. Check this post https://www.camaroz28.com/forums/sho...d.php?t=525743

raroz28

Either way I would not drive the car with oil pressure that low. Find the problem before you drive it too much.

twistedbowtie

thanks man thats what ive been looking for. i dont think its that but is possible.

i know i really want to fry my bearings. im gonna install a new gauge and see what it reads.

twistedbowtie

i just thought about something my windage tray was not instaled on the motor. could that be my problem?

raroz28

I would have left it in, it helps keep the oil in the pan and not slinging all over your rods and crank.

As far as losing oil pressure, I doubt it. I know a lot of guys who run without windage trays and they do not have oil pressure issues.

twistedbowtie

yea it was a thought. i didnt mean to leave it out i was having it cleaned and put the motor together then realized i left it out. thanks

raroz28

You should be ok without it. Lots of guys run without it, some claim there is a HP gain from running without it, but I don't know if that's true or just an internet rumor.

SC/TA

If anything the lack of a windage tray will cause low oil pressure at high rpms because the crank whips the oil into a froth. I dont think it would cause low pressure at idle.

twistedbowtie

yea i agree