oil pressure?

**divinezx9** · 02-22-2007, 05:29 PM

i just bought a high mileage lt1 bird. what should my oil presure be at? is it supposed to drop at idle almost all the way?

**BlackLT1Z28** · 02-22-2007, 06:33 PM

From a cold start-up to a warm idle, the oil pressure will drop a good amount. Cold start, mine's all the way up to 80psi, but once it gets to operating temp, it drop past the half-way to about 15 if I remember correctly. Its been awhile since I've driven her.

**01Z28M6** · 02-23-2007, 08:18 AM

The minimum pressure according to the service manual is 6 lbs. However, don't trust the gauge until you have changed / checked the pressure sensor. My 100k LT1 was showing about 12 lbs at idle. I replaced the oil pressure sender and it has never dipped below 25 lbs.

**dafaic** · 02-23-2007, 12:47 PM

where as mine was bottoming out and putting the check gauge lite on. I replaced the sensor and the thing got worse. Installed a mechanical gauge and found it at 1000rpms at 6-8psi fully warmed up and about 50 at cold. The stock gauge is right at 10 off on the low side.

**SkreaminHawk** · 02-23-2007, 03:36 PM

On my '94, in the past 5 years (23k miles), at a hot idle, in gear, the pressure has never been above or below 6-8lbs. As soon as it reaches just a hair above idle, it jumps right to 40lbs. But you have to remember, the LT1s have high volume pumps, not high pressure pumps.

**BlackLT1Z28** · 02-23-2007, 04:14 PM

I remember reading somewhere that the pressure should be at 40psi at 1K RPMS and 80psi at 2K RPMS.

**dafaic** · 02-23-2007, 07:34 PM

minimum specs is 6psi at 1500 rpms per another board. Nascar rule of thumb 1k rpm equals 10psi. The ls1's have really high oil pressure and fuel pressure and is not consistent with lt1.

**5.0THIS** · 02-24-2007, 02:15 AM

Originally Posted by BlackLT1Z28

I remember reading somewhere that the pressure should be at 40psi at 1K RPMS and 80psi at 2K RPMS.

Originally Posted by dafaic

Nascar rule of thumb 1k rpm equals 10psi.

Thats not a NASCAR rule of thumb. It's an old Smokey Yunick rule, and he made it decades ago. Oil has come along way, and just because an engine doesnt make 10psi per 1000rpm doesnt mean a thing. Must current Cup engines only make about ~50psi of pressure, and they can turn upwards of 9000rpm. I race circle track myself. We wind our engines up to 7000rpm, and never see much more than 50-55psi of pressure on the straightaways.

**sscamaro1384** · 02-24-2007, 10:26 PM

i have a 98 ls1 with over 160k and since i've had the car at 120k the oil pressure has always been 20-35 psi once the car is at operating temperature. i run quaker state 5w 30 synthetic and usually a fram oil filter. what do u think is the cause for the low oil psi?

**dafaic** · 02-25-2007, 05:43 AM

^ then what are you worried about. We are talking 6-8 psi at idle and you got 25-30...Try running a 10w-30 Mobile One might increase pressure some...I only use the mobile 1 supersyn extended performance 10w-30. If i didn't use mobile 1 it would be royal purple or amsoil. No way I would run anything else... I also only use mobile in the other 2 cars the 5000 mile oil.

It hurts me to see some bs oil put in these cars just like some d.a. up at murphy putting 87 in his TA. Or another one putting 87 in his 05 vette.

**01Z28M6** · 02-25-2007, 06:03 AM

Originally Posted by sscamaro1384

i have a 98 ls1 with over 160k and since i've had the car at 120k the oil pressure has always been 20-35 psi once the car is at operating temperature. i run quaker state 5w 30 synthetic and usually a fram oil filter. what do u think is the cause for the low oil psi?

Hoping divinezx9 doesn't mind the thread being jacked but your oil pressure isn't far from what my 01 with 65k is running when hot. Low oil pressure on high mile engines is usually a sign of worn cam bearings. If the rod bearings are worn enough to run low pressure there is a deep knock and failure is imminent.

**sscamaro1384** · 02-25-2007, 07:15 PM

what oil weight should i be using. i still use 5w 30 synthetic. should i try a different weight or a different brand of oil and oil filter? what s the normal oil psi for an ls1? at idle and at operating temp? any help greatly appreciated.

**5.0THIS** · 02-25-2007, 08:22 PM

Originally Posted by sscamaro1384

what oil weight should i be using. i still use 5w 30 synthetic. should i try a different weight or a different brand of oil and oil filter? what s the normal oil psi for an ls1? at idle and at operating temp? any help greatly appreciated.

The oil you're using is fine. If your pressure is 25-30 at idle, everything is ok. The only thing I'd get away from is the fram oil filter. Fram is junk. Go for maybe a wix filter (sold at NAPA as NAPA gold series). They're not too expensive and are a better piece than fram.