Oil Pressure?

[BarbeeT]

Does anybody know the (average) probably not the right terminolgy, but...
Just completed a rebuild, started the car oil pressure 50, took it about 3 blocks to the gas station now its at 10... I guess I have to wonder, now what could be wrong? What type of pressure should I be expecting???

 

[Jerryl]

Does anybody know the (average) probably not the right terminolgy, but...
Just completed a rebuild, started the car oil pressure 50, took it about 3 blocks to the gas station now its at 10... I guess I have to wonder, now what could be wrong? What type of pressure should I be expecting???

On a fresh motor, i would expect (with 30 wieight oil);
65-70 cold
15-25 hot

What clearances were used?
Did you blueprint and verify clearances of the oil pump?
Maybe the gauge is inaccurate (??)

 

[BarbeeT]

Oil Pressure

What would be the easy way to see if the guage is bad? The clearance was done by Westtec a local performace shop around here. Its a high volume oil pump and it was shimmed it was done on a stock motor, now that the motor is not stock, would that all need to be changed? On one of the threads that I read, it stated that if using a high volume pump, you should use the stock spring? Does that make any sense?

 

[Jerryl]

What would be the easy way to see if the guage is bad? The clearance was done by Westtec a local performace shop around here. Its a high volume oil pump and it was shimmed it was done on a stock motor, now that the motor is not stock, would that all need to be changed? On one of the threads that I read, it stated that if using a high volume pump, you should use the stock spring? Does that make any sense?

The spring only releases pressure when oil pressure is higher than the spring rating. So, a 60 PSI spring, will release pressure at >60 PSI.
That does not explain the 10PSI hot pressure.

What does "Its a high volume oil pump and it was shimmed" mean?
Does this shop have experience with TB engines?

 

[cool 84]

One of the biggest things that affects oil pressure, especially hot pressure is the clearance between the ends of the gears and the cover plate. Usually the gasket kit will come with several gaskets of different thicknesses to adjust this clearance.

 

[BarbeeT]

OIl Pressure

Ok, let me try to get right..... When the performance shop put on the high volume oil pump it was put on the engine when it was stock. Over the winter I had engine work done on it. Could that be the problem. The performance shop did all the clearances. We dont know what the clearances are tho.

 

[Jerryl]

Ok, let me try to get right..... When the performance shop put on the high volume oil pump it was put on the engine when it was stock. Over the winter I had engine work done on it. Could that be the problem. The performance shop did all the clearances. We dont know what the clearances are tho.

Was the pressure higher before the rebuild?

 

[BarbeeT]

No, the oil pressure is the same as it now. When its cold the oil pressure is 50/60 and as soon as it gets warm, it goes down to 10 and stays there no matter what the RPM's.

 

[cool 84]

No, the oil pressure is the same as it now. When its cold the oil pressure is 50/60 and as soon as it gets warm, it goes down to 10 and stays there no matter what the RPM's.

No matter what the rpms? I assumed this was only at hot idle. Don't drive it like this or you will hurt it.

Just trying to clarify, once hot, it's at 10psi at idle and if you rev it, it stays at 10psi?

When cold, does the oil pressure change with rpm?

Even if the shop forgot an oil galley plug or the front cover had a porosity issue, I would think that oil pressure would change with rpms or be at 0 all the time.

I would start with a new guage and then check out the relief spring and valve.

Edit: This is probably not a hotair specific problem. You will get a bigger audience if you post in the general tech area.

 

[BarbeeT]

Yes, at hot idle its always ten.
Just trying to clarify, once hot, it's at 10psi at idle and if you rev it, it stays at 10psi?

Not really sure, but I will check it out.

 

[cool 84]

Yes, at hot idle its always ten.
Just trying to clarify, once hot, it's at 10psi at idle and if you rev it, it stays at 10psi?

Not really sure, but I will check it out.

That would make a huge difference in the diagnosis if the oil pressure rises with rpm like it should. 10psi isn't necessarly that bad (as long as it rises with rpm). I drove mine around for years with between 5 and 10 psi.

If it was the same with the old motor as it is with the new one I would look at the pump. Changing to a thinner gasket in the cover plate can make a huge difference.

Also, what weight oil are you running? 10-40 works well but whatever you run, make sure it has the much needed ZDDP that they recently took out of many oils.

 

[BarbeeT]

Oil pressure

Okay someone... Maybe have the problem figured.. What color is the stock oil pressure spring? In this kit we got from postons, we have a plain, white, yellow, orange.

 

[cool 84]

Okay someone... Maybe have the problem figured.. What color is the stock oil pressure spring? In this kit we got from postons, we have a plain, white, yellow, orange.

It's not the spring unless it's broken. It controls the relief pressure. For example, if the spring is set for 50psi, it's going to be bleeding off pressure after 50psi. There's no such thing as a 10psi spring.