LS240sx

iTrader: (12)

I had another post going about my car no having any Oil pressure. Well we fixed that to where it gets up to 40-50 psi cold (40-50 degrees outside). But the motor is still worrying me. Im only getting 20 psi fully warm.

Ive heard mixed emotions on this. 20 psi is good or its horrible
My last LS1 motor had the same pressure and spun a bearing but it was a 100K+ motor with stock oil pump.

The new setup has a LS6 oil pump with a GTO Oil pan and Pick up. I just installed a new O ring and made sure the pump was in good order.

The bearings in the motor are actually a little tighter clearance than what is recommended but nothing major so in theory my oil pressure should be higher than average.
Do the GTO pans and pick ups have clearance problems? Is my bleed off spring bad? The Pump in this same motor before it detonated and was rebuilt was pushing 40-50 psi warm. Now with new oring and all it only makes 20 and I made sure nothing was pinched, spacer are on right, Oil pump is great condition, pickup tube sits flush, O ring is good and all oil galley plugs are in place. Im stumped.

Im going to buy a Melling but I dont want to just mask a problem if there is one.

The motor has ALL new bearings

ramairws6

iTrader: (33)

One question I ask is do you have the right filter on it? The filter should have the built in anti drain back valve built in it. Some of them do and some don't. I have found that this will effect idle oil pressure somewhat. Just another thing to check out. Traver

LS240sx

iTrader: (12)

K&N Gold the best you can buy

ShoddyHog

iTrader: (1)

How are you monitoring your oil pressure? Reason I ask is that I have a LS2 E40 PCM and about **** my pants to find 20 psi hot with a brand new SLP pump after my cam install. Come to find out, there's a bug in HP Tuners and with my PCM it was reading HALF of what it really is.

Gerry

ta_06374

iTrader: (7)

I had the same oil pressure when hot (20psi). Went to the long style oil filter and gained 10psi. Running 10/40 mobil 1

White_Hawk

iTrader: (3)

Low pressure at idle is almost always main bearing clearances too large. Did you measure them yourself? What were they?

-Geoff

HTMtrSprt

You don't specify enough .... is it 20 PSI max, even at 5000 RPM? What oil are you running? What is the clearance between the pickup and the bottom of the oil pan? Do you know the lifter to bore clearance?....it will have a huge effect on oil pressure. If it has 20 PSI at idle and goes up to, say, 40 PSI at higher revs, that alone will not cause any engine problems.

btw - I have seen quite a few problems with Fram oil filters causing a lack of pressure.

turbo408stroker

I had this problem when i built my 383. It would start with 70psi cold and when hot go to 20psi. The lifters sounded like they were calapsing front cam bearing walked in the block never new it until i pulled the motor i had to cut it out good luck

Racer Buzz

iTrader: (1)

Did you replace the cam bearings during the rebuild or cam change process? My engine builder says he has recently discovered that the GM part cam bearing are considerably tighter in their clearances than after market bearings and that can have a big effect on oil pressure.

Agree with previous post that the main bearing clearances are critical but a lot depends on if those clearances were measured with plastigauge or a dial bore gauge.

Also I've read several other posts where the oil pumps vary a lot on there output pressure.

Good Luck. Hope this helps.

WAHUSKER

iTrader: (4)

Well, since it's an LQ9 block, it "might need" a dbl o-ring on the pick up tube. My race motor doesn't, but my truck motor seems to. I have to pull it back apart (3rd time). Just a thought.

pkincy

iTrader: (1)

I have had cam bearings walk or loose in two rebuilds. The second rebuild was done to replace crank, con rods and all bearings after driving my car with a 20-25 psi idle oil pressure and 40 psi at rpm.

I would identify and fix the problem. First buy a good guage that fits where the oil filter is to get an accurate oil pressure. If it is still low pull the motor.

Perry

LARRY01Z28

iTrader: (28)

good info here. thanks.

racecar

I had the same experience, I replaced cam bearings after having the block honed. It took three sets of aftermarket bearings to get all of them under
.003.