MBC Racing

iTrader: (3)

I already did the search and read up on this stuff. However, I want to make sure it isn't something else before I tear stuff appart.
I have a 108k ls1 that I am using for road racing. I just did a a4 to m6 swap on it and pulled the motor to fix some leaks, install a canton pan and the old cam from my ls2 GTO. Motor made good oil pressure befor the cam swap, but had an erratic gage. I took the sensor off my other ls1 motor and replaced it. From what i remember, it would show ~60 psi when hammered. I replaced stock cam with ls2 cam and ls2 cover for cam pick up. I reused the stock oil pump since it seemed to be working well before and had oiling issues with the high volume pump I had in my other car (too much oil in the heads during sustained high rpms).

Finally got motor in car and pulled fuel pump fuse and cranked for a while to try to build pressure. Didn't seem to show on gage. I have a remote filter and accusump, so I figured it was trying to fill a LOT of are. Took 9 qts to fill it all up. once running it had pressure, but was around 35 psi. does seem to ever go over 45 or so when I rev it. Used to before.

I am running 15/50 mobile one. Yes it is thick, but when oil temps were in the 230 deg range, 5/30 was showing too low a pressure for my liking. 50 acts like a 30 at that temp.

From what I can tell, I torqued the cam retaing plate to specs with a tq wrench, o-ring looked good. Is it possible the pump went bad??? Not sure how a g rotor style pump goes bad??? Maybe relief spring is stuck? worked fine before I tore it down, so don't know what happened.

Is it possible that the dims on the ls2 stock cam are smaller and it is bleeding off pressure there? Wouldn't think so, but????

I read about the oil filter, but don't understand how the filter could cause a drop in pressure if stuck in by pass mode. Could possibly cause a drop if plugged and sensor is on the down side of the filter???

Gage is still erradic.... could it be the pump all along and the sensor was OK... now that it stil does it with a known good sensor?

I am so sick of working on this fkng car I am going to try to hook up a mechanical gage to see what the pressure is. According to the gage on my accusump it only is getting to 40 psi.... my other car used to keep it charged at ~75psi. Either way, if it is only getting 40 psi max, that aint gona cut it at 6500 rpm.....

I also replaced all the rod bolts with arp 2000. Inspected all the rod bearins and they looked great. Had good psi before, so had to be related to cam swap??????

thanks for any info/help

LS1-NAVY

iTrader: (1)

might have pinched the o ring putting it back in.

00pooterSS

iTrader: (40)

I broke my oil pressure sensor doing my intake and picked up a used one from a buddy, after ward my gauge bounces every once in a while, never did before, no other changes.

MBC Racing

iTrader: (3)

If I have 30 psi at 800 rpm, and no bubbles, would it be the pick up tube or more likely the spring in the pump or the gasket on the cam retainer plate???

Pressure doesn't seem to go above 40 psi. At least that is the most pressure I am seeing on my accusump. If the o-ring is pinched, don't you see bubbles in the oil? and wouldn't it be even lower pressure??

It looked like it would be a **** to try to remove the pick up tube from the oil pump with out removing the pan.......

MBC Racing

iTrader: (3)

I took it for a ride around the block with the accusump OFF. In off mode, it will only charge up to the max uptained pressure, but not RELEASE the oil back to the motor.

I looked at the factory gage and it still bounces around somewhat. The 30 psi warning light will stay off as long as the motor is above ~750-800 rpm.
I did oddly see the pressure go up when I would turn??????

Pressure on the gage seemed to go up when I would get on it, but was not consistantly going to the same psi every time....

when I got home, I looked at the gage on the accusump and it showed ~65psi. Well, that is plenty good.

Question is why is the gage fluctuating (did same with old and new sending unit)?????? Can a pinched O ring cause this and maybe this is why it goes up on some turns???

Next option I have is swapping out the cluster to see if it is screwy with the gage???

At this point, I am thinking I don't need to pull the front cover and stuff??

What do the experts think?????

Thanks!

mred

iTrader: (5)

good topic but yet no answers.
i swapped to a high mileage oil and just now started to notice the oil pressure is moving around.
never did it before,till yesterday when i changed my oil and filter

littlefranks

i know this might sound funny but how far away is the pick up from bottom of pan.

MBC Racing

iTrader: (3)

Update.....

I ended up replacing the cam retainer plate (orange seal was almost flush with the plate), o-ring on pick up tube (od and ID were both flat, no longer round on the edges) and installed an SLP oil pump.

Problem is solved. ~50 psi cold at idle and ~75psi when on it. I don't have any oil issues with it comming out the breather when auto crossing or on a road course, so not sure if it is due to a stock motor or one with High Miles or both...... either way, problem is solved and the thing has just been dominating its class so I am HAPPY as hell with this car!!!