rwj383

I've had a 454cid LSX iron block build in my 01 Coupe for about 7 years now. Oil pressure has always been finicky at best on this motor. At temp the pressure resides at 22psi at idle, 40psi at higher rpm. I've had the motor out several times in last 7 years for various reasons, and always addressing the oil pressure issue while motor apart. We've tried new rod & cam bearings, blueprinting each time to verify clearances. Several oil pumps, block has been torn down and tanked/cleaned several times, passages are clean, barbell in rear of motor oil galley replaced with new, oil press sensors...you name it, I've tried it. At each teardown the bearings look great despite the lower than normal oil pressure. But I still dont like it. On really hot days the idle pressure can dip below 20psi (>100F outside, engine coolant = 200F, oil temp = 225F). While past teardowns dont show any adverse issues to this low pressure, I still want to fix or improve it, witjhout pulling the dam motor again. I am considering an auxiliary electric oil pump that I can run in series with my external oil cooler lines. Has anyone done this before? Any input on running an additional external pump at all times with the engine mechanical oil pump?

Pounder

Does that block have a one way relief valve ????????

73Corvette

What weight motor oil are you running?

jerkyboy

My brand new built LS-7 (wet sump) is exactly the same way. At super hot idle, I've seen 17lbs. Cold start sits around 32lbs. Warm highway at 2K rpm is 35lbs or so. I've been puckering every time I take it out and I've been watching it like a hawk. My tuner who has seen a lot of these motors and has seen a bunch with oil pressure within this range says I shouldn't worry. His experience is that these motors are built "loose". He ran a similar set up for 4 years with such pressure. For an LS-7, my valvetrain is really quiet (even at the 17lbs).

I have the original engine stand dyno where the engine was broken in. Even then the max oil pressure at 6500 rpm was 55lbs. No one else seems worried about it but me.

BTW, I started with M1 5w30, then switched to Amsoil 10w30. My tuner said most people with my similar set up run 10w40. That's what I will try next.

I'm curious what others say about the external pump. Part of me says "if it ain't broke...don't fix it"... But it bothers the s@#$% out of me too!

K-Spaz

Keep in mind the oil pressure sensor is up high on the motor, so it's not reading the pressure at the bearings. There's tons more pressure down low. There's also lots of oil volume. Yes, new synthetic oils are about like water but they lubricate just fine. My buddy who runs super-gas runs 0W-20 in the racecar. His car shows no oil pressure at idle, he's fine with it. If he blips the throttle the gauge moves and he knows it's fine.

If I were to get concerned about it, it would be when I saw pressure dropping over time. Like, last month at this engine and ambient temp it was at 20psi, now it's 17. That is telling you the motor is changing. But if it's consistent, I'd probably not worry about it.

v8srfun

Flow is more important than pressure. If you are getting good oil flow with no bearing issues and or oil starvation don't worry about it. It could be that your block has cleaner free flowing oil passages and that is where the reduce in pressure is coming from. I have a corolla with 220k on it and I run 0-20 in it with no issues. Once again I want to drive this home flow is more important than pressure. You should be overly concerned if you have unusually high pressure because that means there is a restriction somewhere but lower pressure with known good components is not a issue.

73Corvette

I used to get freaked out when switching to synthetic because the oil pressure would drop... but, it's all good

rwj383

Thanks for the inputs. I've been building these motors since 2001 and know a lot of other LS builders out there that have also put a lot of wrench time into trying to improve 'low oil pressure' conditions. Many have found out, like me, that the internals are not being subjected to risk with low pressure becuase, as some of you have indicated, there is obvious ample volume keeping everything copacetic. BUT, I still want higher pressure!! ARGH. I would just feel more comforted to beat on the car at the track if the pressures werent dipping to 20 at idle. So that's why Im curious how an aux electric oil pump, if ran at all times, would it help or hurt? Fight with the mechanical oil pump? Scavange? Starve parts of the motor?

K-Spaz

Call me strange, but I'd probably spend my time and money on stuff that needs fixed.

If you really want to have higher oil pressure, put the sensor down just above the oil filter. Pressures will go through the roof. It'll read 80psi at idle.

73Corvette

Spaz you are Strange...

K-Spaz

You will get no argument here.

(edit)
There is a port for it down there. It's just plugged off. Swap the plug and sensor, oil pressure issue fixed.