[laynlo15]

So I recently installed a Lt4 short block and Lt1 heads with BTR cam, dod delete that uses press in plugs and no o ring under the valley cover, it has new oil pump, katech front cover, chain, tensioner, etc Just wanting to see if anyone else is seeing low oil pressures, I'm seeing 20 psi at idle and normal psi on the street. I've talked to one other Zl1 person that said their oil pressure was about the same and another said theirs as around 35 which is what my old motor was. Just checking.

[IneedAZ]

Curious, is the 20psi when hot or both hot and cold? Seems low to me.

[collinms]

That was what mine was hot before the oil pump let go. Another sign was when at WOT, the pressure would go to max on the Guage.

[laynlo15]

That was cold and hot. We may have gotten a bad pump, we had to wait over 2 weeks to get it as they were on back order because of the December Holidays. We are checking the pressure at the filter and at the valley cover today to see what the difference is between the two. GM has a max between the two places to check it on determining what might be failing. I'll post once we find out this morning.

[IneedAZ]

I assume the pump was the latest revision? That totally sucks...all that work and have to do it over again.

[laynlo15]

Pump appears to be ok according to the scan tool Matt uses and yes its the latest and greatest. We are loosing pressure between the oil filter and the valley cover sensor. He told me this morning its about 30 psi difference according to his GM scan tool

[IneedAZ]

Is the filter reading done before or after the filter? Wondering if just a bad/clogged filter?

[Grumpy1]

I see 33-35 at idle and 42-45 during normal driving on a stock motor.

[IneedAZ]

Originally Posted by Grumpy1

42-45 during normal driving on a stock motor.

that is pretty good...only 1 time have i seen mine go over 40.

[JasonSB]

Mine is 28psi at idle (hot) and around 40psi cruising, depending on RPM. Cold oil should show more pressure at idle.

[laynlo15]

I just got mine back from Matt at the dealership, he helps me at my shop but could not get here so took it to him. It tested 60 psi at the filter and 22.6 psi at the sensor at the valley cover. When you unplug the sensor in the front of the Katech front cover and that will make it go to the high side of the oil pump and pressure goes up to 36 psi. He was able to do that with the scan tool. I'm pulling the blower off this weekend and check the plugs in the valley cover then put the Livernois plate with the o rings back on so we are assured its not loosing it thru the plugs. If that does not work I'll have to pull the front cover and pan to check the bearings. Been there and last time it didn't turn out so good. But the oil pump is good and hopefully the wire that goes down to the pump is not pinched. Fingers crossed. GM guidelines has it within 1 psi on the low side.

[LT4Greg]

My LT4 runs about the same pressure as Grumpy1s ZL1! I have over 10,000 miles on mine now.

[laynlo15]

Thanks for all the responses. I'll have it off this weekend and hopefully back up and going by Monday so I'll let you know the outcome.

[nighttowl]

is there any metal in the oil?
if the pump was not aligned properly the gerotor pump will rub.
you will lose pressure and the oil will look like it has metal powder floating in it.

could be the pressure release as well.

https://gm-techlink.com/?p=12041