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Hello everyone, recently installed a tsp bald eagle cam with all the fixings in my 98 c5. I replaced the oil pump (GM12710303, thought I had a melling high volume as originally posted) lifters, pushrods, cam plate, pretty much everything that would be recommended except cam bearings (they looked decent i thought) Now im running into an issue with oil pressure, it builds good until I get to about 4500 all the way up to 6000rpm where if im doing a pull it drops and stays flat at 40psi. Ive changed the oil and filter and just replaced my oil pressure sending unit as it just went bad. Not really sure why suddenly id be having low pressure issues, anybody have any insight? Haven't hooked a mechanical gauge up to it yet.
Hello everyone, recently installed a tsp bald eagle cam with all the fixings in my 98 c5. I replaced the oil pump (melling high volume and o ring) lifters, pushrods, cam plate, pretty much everything that would be recommended except cam bearings (they looked decent i thought) Now im running into an issue with oil pressure, it builds good until I get to about 4500 all the way up to 6000rpm where if im doing a pull it drops and stays flat at 40psi. Ive changed the oil and filter and just replaced my oil pressure sending unit as it just went bad. Not really sure why suddenly id be having low pressure issues, anybody have any insight? Haven't hooked a mechanical gauge up to it yet.
which o-ring did you use, and how did you select it?
and did you have to force the pick up tube back into the pump? or did it just go in easy?
Any particular reason you with with the HV oil pump? It is not doing you any favors on a stock engine.
Ok so I was misinformed. I ran with the GM12710303 pump which is apparently stock pressure and volume, which is a little silly its called "high performance" in my opinion. And the pickup tube went in just fine if I recall with a gm blue o ring. I'm going to hook up a mechanical gauge and verify pressure before the end of the day.
Did you check the cam bearing clearance? Out of spec bearings can cause oil pressure problems.
No I didn't, if it were cam bearings wouldnt it be a constantly low oil pressure concern? It builds great pressure until I get on it above 4500 thats when it drops.
What spring is in the pump? Could it be dumping pressure early?
How much pressure at idle?
Did you cut the filter open after you changed it?
Cold idle is 40-50psi, when hot its 20-25. The spring is whatever comes in the GM12710303 pump, i was mistaken in thinking it was high pressure or high volume, thats the one I installed. Do you know how pressure would act if you hit the regulated pressure? Like does it stay at that regulated pressure or does it drop off like that?
I would expect it to drop a little but mostly maintain. Unless the valve is sticking.
I havent really seen a OE pump go bad unless it had 300k+ miles on it. I would have probably left it alone.
Did you clean the lifters well before install? Did you do new lifter trays as well?
They were new LS7 lifters in sealed bags and weren't dirty or anything, and yes did lifter trays. And i figured it wouldnt hurt to throw an oil pump in while it was out, oh well
Lifters typically have a sticky rust preventative coating on them that needs to be washed off in solvent before being used. Its possible there is a plugged up one or a few.
Lifters typically have a sticky rust preventative coating on them that needs to be washed off in solvent before being used. Its possible there is a plugged up one or a few.
You are suggesting that a plugged lifter would not impact oil pressure from idle to 4500 rpm, and only impact oil pressure from 4500-6000 rpm keeping the oil pressure at 40psi ?
Lifters typically have a sticky rust preventative coating on them that needs to be washed off in solvent before being used. Its possible there is a plugged up one or a few.
Huh, well, guess I should've paid attention to that then, didnt know that. You think I would notice a plugged lifter? Nothing sounds too noisy and power feels good
Huh, well, guess I should've paid attention to that then, didnt know that. You think I would notice a plugged lifter? Nothing sounds too noisy and power feels good
The faster you get a mechanical gauge on the motor, the faster the speculation stops.
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