smws6ta

iTrader: (5)

Friends car just rebuilt a LQ9 with a melling oil pump. High volume/velocity. IIRC 10296. At idle has 20 psi, on revs goes to 40 psi.

Start ups for last 4 days were around 70 psi. Changed a rear main seal today that was leaking and oil change it drop to 20psi at idle.

All new bearings for cam, rod, crank


Normal or something else?

PREDATOR-Z

Did your friend blueprint the motor?
The bearing tolerances are probably out of norm if not done properly.

sgtrgpfdps

When my stock TA idles 45 psi fully warmed up 90 out side.

Sick Z28

It might be your oil pressure sending unit mines was doing the same thing but at idle mines only had 10 psi and at wot it 35 psi so try the oil pressure sending unit

handyandy496

iTrader: (9)

get a real oil pressure indicator to see if the dash is working right.

96lt4c4

iTrader: (5)

Too much bearing clearance or bad oil sender.

My new motor idles at 50 psi HOT. And goes up to at least 70 psi when reved. That's with the same pump you have and the low pressure spring installed.

smws6ta

iTrader: (5)

It was short blocked by a shop. New bearings all around

She has mechanical Oil Pressure gauge + the OEM gauge. Both read the same and react the same.


Shop told her to use 5-30 for break in then switch over to 10-30 after 500 mile break in.

She replaced the RMS and gasket on the back cover and did an oil change and now the pressure dropped.



My main question is with the new oil pump would it have this low ready at idle and move up as you rev up to normal psi? When she accelerates it holds the psi slightly above 40psi around 2000 rpms, it does climb if she revs up and holds, doesn't spike up and drop unless she lets off the pedal

wildcamaro

iTrader: (15)

Yea I see alot of people on here having oiling issues bc of "rebuilding" because of incorrect bearing clearances...plasticgage isn't the proper way which a lot of people use... The only correct way is to use the proper tools (micrometer , bore gauge, etc)...too many people just buy standard bearings and go, sometimes you even have to use two different bearing sides to get proper clearance...

smws6ta

iTrader: (5)

found the problem oil barbell was missing. ordering replacement now.

high n dry

iTrader: (18)

that's what i was going to say!

niscur29

Was thinking that too. I made myself several notes to make sure I didn't forgot the front and rear oil plugs when I rebuilt mine.

chrisfrost

iTrader: (8)

Plastigauge can be really close if done correctly. I believe most poeple only put a piece on 1 side then torque, then remove and You won't get an accurate measurement because it May be pushing the journal to 1 side a little anyway.

If You put 2 pieces opposite 1 another and torque, then remove and measure it should be accurate enough that along with measuring using calipers and micrometers with a .001" resolution good enough 4 a "budget" build,,,,,,,,I imagine some of You may not agree and probably most that don't agree can afford calipers with .0005" resolution . Although maybe more of us than us poor guys n gals think can afford tools with more resolution. There was a thread in this forum a cpl weeks ago or so where a guy was saying there is a budget caliper 4 like $80 from,,,,,,,don't remember,,,,,,,,,,and put a display from the expensive Japanese brand on it or something like that and total cost was maybe $150 and You had a tool with .0005" res that is supposed 2 be accurate ,,,,,,,,,maybe 1 of You poeple knows what I'm talking about