I recently installed a cam, oil pump, and timing chain on my car. The oil pump is a ported LS6 that has been shimmed for more pressure. Now on to the bad news. The hotter my car gets, the lower the oil pressure goes. At idle at normal operating temperature it stays around 20 psi on any normal day. When it's cold, it's at about 50 psi, and slowly goes down as the temp goes up. At idle the the pressure isn't constant, but the RPM's are; it kinda flickers around. And before the cam, it was a little less than 40 at idle, no matter how hot the car was.

I'm seriously thinking it's just a pinched o-ring and not a bearing. Well actaully I'm hoping, praying and everything else that it's not a bearing. I was thinking if it was a bearing, it would only lose pressure to that single bearing, and not the entire engine. Am I correct?

I'm gonna tear it apart in the next few days and replace the o-ring, hoping it helps. Any other ideas??????????? Or any tips on getting the pickup tube bolted to the oil pump faster without pinching the o-ring?

Thanks
Ryan

 

You cut the o ring. Replace it and you should be fine.

 

whatever you do don't run it! One of my customers/friends ran 20psi at idle and ended up slowly destroying the bearings, starting from the back to the front they gradually got worse.

-Sly

 

I had pretty much the same problem. I thought about all the possibilities just as you have. Mine turned out to be something other than all the possibilities that I have read about. Some how, I had placed the 3 hole spacer in backwards and that only allowed for half the nomal hole size. This was something I never thought about. I guess the spacer fell out when putting the oil pump on and then I stuck it in wrong not even thinking that the bolt holes would line up other that correctly. Good luck.

 

If you absolutely want to make sure you do it right the first time you can drop the oil pan to do the oring. That way you can put the pickup tube in perfectly straight with no fear of pinching the o-ring. Getting the pan off is hard cause you have to drop the k-member pretty far, but given the choice between taking out the radiator/water pump, timing cover, oil pump, i think i'd go with dropping the oil pan. I've done it both ways. Oh yeah if you have a double roller timing chain you can also elongate the pickup tube mounting hole so it doesn't put stress on the o-ring while you're down there.

 

my 98 does the same thing. i think it might be normal for our year...

 

the 98/99's are known for their oil pumps going out randomly. When they start doing that you better replace it.

-Sly

 

Unless you want to end up like me, buying a entire new short block because of oil starvation!

Seriously, invest the $150 in a ported oil pump, you won't be sorry.

 

Or like my friend Tim, having to buy a new shortblock because of the same reason.

-Sly

 

the pressure doesnt flucuate its just lower...could this be due to the diff pcv system?

 

Actually the oil pump yrs were 99-00, 98's were fine.. also it is not uncommon for oil pressure to flicker a LITTLE bit at idle, mine does, but my op is about 28-30 when warm, and about 40during very light driving and 40 at idle when not quite warm.

 

20 PSI at idle is fine. The LS1 motor only requires 7 PSI/ 1000 RPMs.

 

The best thing to do, is get an accurate oil pressure gauge, and see what it truely is before you go ripping it apart..

 

I JUST replaced the oil pump w/ a ported AND shimmed LS6 piece when doing the cam install.

Speed Demon didn't want to dyno tune my car b/c he had a customer throw a rod through the block w/ the same oil pressure. I'd rather be safe than sorry.

 

You would think so but I have seen a few people running 20psi and they have all toasted their bottom ends. I'm just stating from experience.

-Sly

 

If the oil pressure was good before the install then check the o-ring and the spacer plate on the right of the oil pump.

-Sly

 

Where did you get this info, Carl?

Thanks man.

 

From a GM tech service manual

 

Hes serious that what it says. And GM says a motor doesnt have a oil consumtion problem till it burns a QT every 1000 miles. The oil wieght you use also can effect oil pressure also.

 

How many hours would it take to swap an oil pump?