BlackSS/SC

I swapped a l92 into my 04 cts-v and finally fired it up today. I'm getting 30-32 psi cold and 12-15 psi warm at 950rpm. I swapped senders and same thing. It's not making a noise. Very quiet.

It's a 08 l92 with a custom cam motion cam, ls7 lifters, 17801830 oil pump. I swapped the reluctor to 24x. I sent the block to the machine shop for honing, cleaning and had new cam bearings put in.

I reused my main and rod bearings. My main clearances were 1st .0015, 2nd .0015, 3rd .0015, 4th .0015, 5th .0015-.002. All the rods were .0015ish. Measured with plastigage.

The machine shop installed the front plug, I installed the barbell in the back, it's flush with the block. But now realize it should be out just a bit. But this wouldn't cause this would it?

The only other thing I can think of is if the oring got damaged on the pickup tube. But I thought I was very careful here. Does it sound like that kind of issue? Any way I can test this before pulling the engine again? Or dropping the front cradle and suspension.

racecar

Either oil pump o ring, or pickup to close to bottom of oil pan.

CAMSTER

iTrader: (10)

Are you using double timing chain, if you are the spacer with the oil transfer hole could be on upside down causing a mismatch of about 40% and as much oil pressure drop.

I never change cam bearings on a block that had good oil pressure as a rule.

I sure hope is not the case.

Your barbell is not to blame.

Did you install the rear engine cover with it's thin ring in it, I always glue that sucker in place just to make sure cause it must withstand the blunt of all the oil pressure.

BlackSS/SC

Single row timing chain. I dropped the oil pan again and put a new o-ring in, no help. The original cam bearings were scored badly. I bought this engine used. What thin ring do you mean for the rear cover? All I remember doing in the back is the barbell, rear main seal & the cover itself with new gasket. Reused the lifter valley cover & intake gaskets as they looked new. Reused the cam retaining plate as it's seal looked great.

No metal files in it, no noises. I switched to 15w40 and am getting minium of 21psi hot and rises fast throughout the rpm.

Stephen Griner

iTrader: (17)

So I see that this is very old, But did you find a fix? I have seen where the pressure relief valve on the oil pump gets stuck open and sometimes it is a clogged screen in front of the pressure sensor and sometimes it is a pressure relief valve issue in the oil pan??

Kamaro

There is a small screen filter beneath the oil pressure sender on the valley cover, sometimes that filter get clogged and will indicate low pressure due to restrictive oil flow to the sender. Try to replace it, it may be the magic solution.

Stephen Griner

iTrader: (17)

Wouldn't you have a low oil pressure reading all the time(engine hot or cold) if the screen was clogged? I had a low pressure reading with the engine warm and 80* outside temps or higher. It dropped to somewhere around 15psi. L92 Denali. I ran a quart of Marvel Mystery Oil in the crankcase for a few days and then changed the oil with Mobil 1 with a k&n oil filter. Seems to only drop to 20psi now. I'm keeping an eye on it! I was thinking of running a can of seafoam in the oil before the next change.

64post

iTrader: (5)

Why not buy the Autometer brass fitting with16mm X 1/8" NPT threads, install it in the galley plug on the front left hand side of the block, install an oil pressure gauge in the 1/8 NPT hole but first warm up your motor some, you'll probably have to do this with the drive belt off because to access this galley there can't be anything bolted to the left hand side of the block. Check warm engine oil pressure there and then on top/rear valley oil galley location. Compare pressure readings, if it's low in the front, stop. You have oil pump/pick up issues, if it's a high reading in front but low a low reading in the rear you have too much clearance in your bearings, a cam bearing coming out or something that requires complete
disassembly. Once you know your pressures you can plan a weekend to remove and disassemble your motor or just fix the pump and pick up.

Stephen Griner

iTrader: (17)

Sounds like a good idea! Thanks!

FD3SLS1

iTrader: (1)

I put a L92 Longblock in my 05 CTS-V also with a brand new high pressure melling select oil pump and I see around 16-17 PSI at the lowest at hot idle (oil temps 220-230). I have about 10k miles on it with no issues.

Here are my thoughts on it. Since the L92 comes with a high volume oil pump from the factory due to the VCT system I'm thinking the clearances in the oil passages may be bigger causing a reduced pressure reading at hot idle. Off idle and driving pressure is normal. That's the only logical reason I can think of why my engine has lower than normal oil pressure.