I am about to give up on this car and junk it....... It has a 5.3 swap with an ls6 cam, f-body oil pan and ls1 intake in a c4 vette. I already destroyed one engine last year by driving and having it lose oil pressure. I ran it fine for a week and then it lost pressure driving it and started knocking. I took it all apart and found a pinched pickup tube o-ring I thought was the culprit.

Well I have put probably only 100 miles on this engine of easy driving/tuning and it has had GREAT oil pressure. I was doing some VE table tuning today and of course in the middle of doing some higher rpm tuning it lost oil pressure. So I shut it down and it is back home now but I don't have a good feeling about this at all, I am thinking that the bearings on engine #2 just went bye bye. I got the ls6 cam used from a buddy in good shape working fine from his car.

Any ideas on why it was perfectly fine until some high rpm tuning and then a sudden loss of oil pressure??? Or at least where should I start looking?? I am guessing I am just screwed and just wasted a pile of money and labor AGAIN.....

 

I should state that when I shut her down it had only about 10-15psi oil pressure on idle before I cut it coasting into the drive. It was not absolutely 0

so after reading some threads on a few other forums. Is it possible the 5.3 oil pump isn't made for the higher 5500-6000 rpms I am running this thing at and the pressure relief valve is stuck?

 

nobody? I am thinking that the same problem on 2 different engines it has to be due to some of the parts swapped. The only parts I can think that were the same on both that would affect this at all would be the pan/pick-up tube? they were both brand new OEM f-body parts so I am just having a hard time believing that they wouldn't have the correct clearance between the pan and tube.....especially since the end of the pickup tube bolts to the pan in the correct spot. Only other parts that were switched that could even remotely deal with this would be the cam but running with great pressure for lower rpm (<3000) for probably 500+ miles the first time and 100 miles this time, I am ruling this out. Only other part is the harmonic balancer but it is an aftermarket c5 balancer and it doesn't wobble or have any noticable problems so I don't think it could destroy a set of bearings that quick............just wondering if anyone has run into anything like this before.... sooo depressing

 

Sorry to hear of your trouble, 1st thing I would check carefully is the oil pickup clearance to the pan. Also look at the pickup screen carefully, be sure its not blocked. If you didn't loose all oil pressure you should be ok but at high r's if you starved the bearing who knows. Thing is if you revved high and started seeing oil p drop when you backed off it should come back up. Something else is up but its dam hard over the net to help. Pinched o ring WILL cause noisy lifers every time........if the lifters were quiet the o ring isn't pinched.

Carefully measure the pickup to pan clearance and post back.

 

What oil pan are you using
What pick up tube are you using.

Did you remove the metal baffle and clean debris out before reinstalling it on new motor.

 

I am using an f body pan an pickup tube. Or at least that is the part #'s I used to get them straight from GM. I cleaned both exceptionally well before re-installation and double checked the tube and pan for cleanliness and o-ring seating before installation. I will get some clay and check pickup tube to pan clearance here because cavitation due to high rpm seems like the only reasonable explanation for this

 

What oil pump are you using stock or aftermarket. If all GM parts clearance isn't a issue they are designed to be correct.

 

On both engines I used the stock 5.3 oil pump and never touched it.

 

I will check clearance of the pickup tube in the next few days when I get time here.... Maybe by some crazy chance GM packaged a corvette pickup tube in there instead of an fbody and it's too short and runs out of oil when it's sucking more at higher rpms

 

When you installed the oil pump did you center it correctly with shims or just bolt it on?

 

The pump was never removed so it can't be that

 

So after looking at both old pickup tubes between the 2 engines. One had an orange seal (newest engine still in car) and the other had a gray seal.... I see the orange style has an indentation.... Is there a difference between the 2 or are all seals interchangeable. I believe the ls1 pan was smooth like the first engine. I used an orange type seal on the current setup

 

So I got some measurements with a level of the pan depth from where it mounts to the block and from the bottom only the pickup tube to the gasket where the pan mounts to. I got 5.25 pan depth and 4.85 from pickup screen bottom to gasket where pan seats on so that's .4 which is just barely outside of 3/8 and I had a tad extra oil in the pan this time so I'm guessing that clearance is definitely not the issue..... I really just dunno what the hell I'm missing here. I also have just pulled the pickup tube out and the O ring fits snug and is not torn or pinched at all. This engine is definitely hosed because there is a surplus of metal on the pan..... What can take bearings out so quick? Is it the used ls6 cam? I can't see the intake or crank dampner causing this. And those are the only common parts in the swap. Windage tray is an ls1 and installed correctly

 

Any other suggestions before I just throw another engine with a new high volume pump in this thing?

 

post up some pics of everything, maybe it will help. From the looks of those pickup tubes the engine was well worn.

 

I will get some pictures posted tomorrow... And yes this last engine was much more worn than the first from the caking on everything and looking at the cylinder walls. I suppose it's possible if everything else was that worn then the oil pump itself might not have been too happy. The 2 pictures I do have are of the devastation that just occurred in there and the cam that I put in which was way cleaner than the one I pulled out.