EXCESSIVE81

416 ls3. New pump when built. Oil pressure has dropped. at start up is 40 psi. But as oil warms up it drops down to 10 psi. . oil temp is 190 cause car is just ideling but pressure does raise with rpm when blip throttle. opsu, bearing, pimp or oring....would like to hear what you guys think. As this has just happened after few thousand miles.

Also i changed the oil i running 10w40 .... the pump is melling high volume with high pressure spring the red one I think.

nysbadmk8

Could be oring, Could be an assortment of bearings bleeding off oil pressure.

My Ls2 403, with a Melling Does 45 psi at idle hot and 55-60 psi at 2000-2500 For comparison.

EXCESSIVE81

Ya I afraid that it could be the bearings.....that the same pump I have

Sales2@Texas-speed

iTrader: (5)

What are your bearing clearances set at, particularly the mains?

nysbadmk8

Matt, I'm sure I am just speculating that the clearances are wider then factory.. but 10 psi hot idle is still too low.. almost shy of floating the crank.

EXCESSIVE81

Not sure off top of my head but when assembled all bearings specs where exactly what Callies said they should be

67SS509

iTrader: (25)

Callies' specs are too loose for an aluminum LS block and stock oil pump.

nysbadmk8

Says who? Everyone has their opinion on this. I agree that too loose is not good just as too tight isnt ideal either. I doubt callie's specs are the problem.

And its not a stock oil pump, Its a Melling HV

thedak

iTrader: (1)

Mains on my 416 are at .0019 Rods are at .0015

I have a ported and coated LS6 pump.

10W-30 oil puts me at 40psi hot at idle.

CJJones87

iTrader: (3)

10 psi sounds awfully low. My 250 mile old iron 408 idles with about 55psi hot. On a cold start, it damn near pegs the factory gauge at 80psi. I'm running 10W-30and my oil pump is a Melling high volume with the high pressure spring in. Granted my block and bearings are set up differently than your aluminum, 10psi is def not enough. Last time I saw 10psi on my gauge was the end of my 346 LS1 to a rod bearing.

nysbadmk8

FYI, theres such a thing as too much pressure too.. 55 hot idle? I bet your pushing 70psi at cruise, Hope you dont have that spring shimmed, anything over 60 psi is just wasted HP.

CJJones87

iTrader: (3)

I know about too high of oil pressure. Builder said it may lose a little after break in when everything gets seated. Not gonna worry about it till after break in and when I get a gauge on it thats more accurate. I'll take my 55psi at idle on my new engine all day over the op's 10psi on his new engine. Call it high if you want... I'm really not worried about losing power to oil pressure in the least bit. To me, its just reassurance that everything is working properly.

nysbadmk8

Id take 35-45 at hot idle over both all day long, but I do get what your saying.. Just too much pressure is just as bad, tends to help bearings spinnnnnnnnnnnn.

fossil

iTrader: (1)

It really depends on bearing clearance and what weight of oil. If your main bearing clearance is .00028 to .00030 (iron block) and oil is 20w-50w and your pressure is 60 psi at idle and over 80 psi at WOT does not always tend to help bearing spin. This is my setup for about 4 years and many others and still running strong.

CJJones87

iTrader: (3)

I hear what you're saying. I'll put a different gauge on it after I get another 1000 miles or so and see what its reading. I have read that the high volume/high pressure spring combination will produce a little more pressure than say a ported LS6 pump, but I don't trust the factor gauge at all. It more so gives you an idea what your pressure is.

nysbadmk8

Wasted Hp, Not saying its horrible problem to have, but its wasted power, and the cam bearings tend to dislike 80psi in what ive seen so far. Not bashing your setup, if it was built for it...

Sales2@Texas-speed

iTrader: (5)

I'd be interested to see what your exact clearances are!

Randy WS6

iTrader: (69)

Just wondering, if you checked your oil sending unit, I cracked mine and gave me the same reading as your did. Are you having a noisy valve train when the oil gets hot ?(no oil reaching the rockers). Or like above your having clearance issues. Just thinking of any reason for the low oil pressure.

EXCESSIVE81

no have not checked the sending unit. and there is zero changes when oil pressure drops. no noise no nothing. i noticed it when the hud not said check gauges and dic said low oil pressure (c6 corvette).... so i limped it back to my shop to diagnose since when at higher rpm i had pressure over 15 psi. if it the sending unit that sure would make my day. hate to have to completly tear the car apart...AGIAN lol. but in my experience when they go bad oill gauge is pegged all the time..... in fact my bonneville is doing that now after my blower install.


as far as the clearances go. i had pics but i cant find them from the build.... but they where right on callie specs. i know because i personaly checked them with calipers and bore gauge as well as plasti gauge during assembly.... i keep looking for pics to confirm. also this has just happened. i have been driving it almost two years with zero issue granted very low miles

EXCESSIVE81

think it time to start looking into building mechanical pressure gauge like i have on fuel rail for double checking oil pressure. there is plenty of room on the oil bulkhead above the filter. i just cut off the oil cooler lines and tapped it for an fittings during my flip drive install so i know there room ....