Segond56

OK, I will try to give the most details possible to help identify the problem. I am hoping its not the bearing clearances but here is the story... Brand new everything in May of this year and the motor is installed in a road race only 944 turbo (once was) and since new I have done 5 track events. From the begining the cold oil Press. was around 50PSI and after the first run at thunderbolt for that whole weekend and event hot off of track as 22-24 PSI. Since then it has slowly been getting lower. 2 events later at Watkins Glen hot off of track was 17-18 PSI and when the oil would cool it would idol at 40PSI. Another note it still did this through the whole process that under load, from 2k PRM to say 35K RPM when accelerating (WOT) while oil is hot pressure would be in the range of 25-30 PSI but when you would lift off of the throttle it would climb higher to near 50PSI, if you would get back in the throttle it would come back down into that 25-30 PSI range. To come to the end of the story I did my last event at Summit Point 2 weeks ago and on a 3 day weekend had to shut the car down due to low oil pressure. One other note the hottest of hot oil temp that I saw was 190 deg. (I have a big oil cooler) and probably 200 deg on water temp, and that was 90 deg. plus days with extreme driving. (Big Griffin Rad). Going into Summit point it was cool the whole weekend but I noticed off track on hot oil the pressure was dropping to around the 16-17 PSI mark. The oil temp never got hot until the run before lunch on Sat. and it when I say hot I really mean warm I suppose, it only got to 150 deg. during this temp run the pressure from 2k RPM to 4k RPM was around 30PSI and at 62K redline top oil pressure was at 38PSI, and the pressure would climb as before while lifting off of the throttle, either going into the breaking zone or simply by just lifting and would climb to close to or just over 50PSI. (I am very interested in why the oil pressure would get higher when you lift off of the throttle, I have never seen that in any of my motors before, anyone that can answer that would be great...) When I came off of the track the oil pressure gauge read 10 PSI and my oil light sensor which is set at 7 PSI started to flicker. I did read in the GM manual for the LS1 that the lowest oil pressure at 1k RPM for idol is 6 PSI and at 4k is 24 PSI. Even with those reports I have never heard anyone with an LS1 with my oil pressure as low without having a problem.

Things I have check are the oil pick up o-ring, in fact I did install from Katech their fat oil o-ring for the pick up, putting that in didn't make a differance. The only 2 things I can thing of is a bad oil pump, mine was a new LS6 pump from GM or bearing clearances. I hope its not the second. If someone has some insight to help out or where else to look I would appreciate it and if any other questions need to be answered I would be happy to. I got an oil analysis kit on oil wear and characteristics and will send that out as well to hopefully provide some insight. Every ones help is appreciated. Thanks.

Vettedrmr

iTrader: (2)

I'd take an oil sample and send it off to Blackstone labs. $25 or so and you'll know the answer. If the metals come back good, then you can aim towards oil pressure bypass valve or oil pressure sensor.

If the metals come back bad, then at least you caught it before the rotating parts are damaged. I'm in the middle of rebuilding my Miata's LS1 after spinning the #3 rod bearing.

Good luck, and have a good one,
Mike

ls1 1990 VN

If it was mine, & i road race as well, i would be changing out the pump & installing a new O ring.

WS6SP33D

iTrader: (2)

This +1

Segond56

One other note I do have a double roller chain, would the spacers that space out the oil pump contribute to this issue??? any thoughts???

chrisfrost

iTrader: (8)

I would look at whatever is used to connect the pump output to the block oil input . It sounds like there could be a problem there .

gMAG

iTrader: (1)

Don't know what the problem is, but I would first change the oil & filter and observe.
If you're running rich, over time your oil will dilute with gas and pressure will come way down.

ls1 1990 VN

Are you pumping air? is your oil frothing? Do you run an Accusump so you aren't getting oil starvation, Pickup not to close that it causes a vacumn.

Just ideas