High Oil Pressure
 

I am working on a zz4 engine. It has sat most of a year as I get it modified for the electronic injectors. Now that I have started it the oil pressure is going up to about 60 psi. The only thing I can think of is that there is dirt or something with the relief valve making it stick. The specifications for a zz4 is 40 psi.

I am getting a second oil gauge to verify that its not the gauge. I have an oil leak around the connector for the oil sending unit and maybe the distributor. Thinking its the high oil pressure.

Anyone have sen anything like this or what are your thoughts?

Using the second oil pressure gauge for a double-check is a good idea. If the pressure still reads high (~60 psi), please answer the following questions:

1. Does the oil pressure read high just at start up or even when the engine has reached operating temperature?

2. Do you have an oil temperature gauge? If so, at what temperatures does the oil pressure stay around 60 psi?

3. What weight oil are you using for this engine, e.g., 10W-30 or 15W-50?

4. When you ran the engine previously, what oil did you use, and what was the oil pressure at operating temperatures?

5. Is this the stock ZZ4 oil pump or an aftermarket? (If aftermarket, which model?)

In my experience, the oil pump's by-pass valve tends to stick open, not closed, thereby reducing your oil pressure considerably. However, YMMV.

Good luck! :cheers:

Thanks for getting back.
1. Oil pressure seems to stay around 60, but not too much data yet.
2. No oil temp, but water temp gauge has been to 190
3. Just put in 5W-30, don't know what the owner had before
4. Owner claims oil pressure was around 40 before, but not to reliable.
5. Believe to be original ZZ4 oil pump, no sign that pan has been off car.

Second Oil pressure gauge will be here tomorrow. I will post the results.
I am putting the Crower 8 port injectors on this engine from the previous racing engine. Have had several difficulities, like 2 bad injectors and a bad MAP sensor. Had to run new battery cables to keep the volts up for the FAST computer. Its been a good learning experience, but wanting to see it run soon.

Dale

This was interesting. At First the second oil gauge was lower than the original one in the car. After running a bit, they both leveled out about the same. I had changed oil and put a bottle of Rislone engine conditioner in the engine the niht before. I ran it for a bit that night. Just wondered if something was in the oil pump relief valve.

I have not yet fixed the oil leak in the back of the block where the oil pressure line connects to the block. A friend tooled up a new fitting to standard NPT 1/8 pipe. It seems the one in the stores is a few thousands smaller that NPT standards.

Just a heads up, the relief valve usually sticks open. If it sticks in the open position you would have low oil pressure. How is your oil filter?