BLACK Z

While driveing it will be up around 50 psi, but at ilde it is down to about 20 or so, I am running 10-30 oil, The motor has about 600 miles on it, my old 305 was always up around 50. So what is normal, I have a brand new gm 350.

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86Z28, GM 350, Jet perf Q-jet & chip Dual snorkel air cleaner, Edelbrock performer intake, Edelbrock headers, Edelbrock cat-back, Off road pipe, MSD 6AL, Accel Super Coil, Taylor Spiro-pro wires, Rapid fire plugs, Jet fan switch, World class t-5, Hurst Short Throw Shifter, Ram Flywheel, Center force dual friction clutch,Aluminum drive shaft, BW disc rear 3.45's & a posi, PBR calipers, Earls braided brake lines, Polygrapite bushings all the way around, poly tranny mount & torque arm mount, Hotchkis lower control arms & panhard rod, Rancho limiter straps, KYB struts & shocks, Gm Wonderbar, Edelbrock strut tower brace, SSM sub frame connectors, Jamex lowering springs, Carbon metallic brake pads, Crossed drilled rotors, Mobil 1 Tranny fluid & motor oil, GM syntheic rear end oil, K&N, Grant stering wheel, 1,200 watt system, Jet Black Paint, 91 Z28 rims, 92 wing, Tinted windows.

ede

depends on where you look or who you ask, but the most common pessure reading i see cited are 10 psi for ever 1000 rpm or 35psi at 2000rpm (i think, i never pulled my manuals to look it up) the factory gauge isn't known for being accurate, i'd check it with a mechanical gauge.

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-=ICON MOTORSPORTS=-

Grim Reaper

Actually, the GM minimum requirements are EVEN LOWER: 7 psi @ idle and 20 psi @ 2,000 rpm are the MINIMUM requirements. As for the 10 psi per 1,000 rpm, remember that is for SUSTAINED RPMS. If you are going to run a sustained 6,000 rpm, then you should have at least 60 psi of oil pressur. But (on a typical street engine), 2,500-3,000 rpm is the normal sustained rpm, therefore you should have at least 25-30 psi for that sustained rpm. The occasional peak rpm of 5,000 rpm (such as when you pass a car) doesn't necessitate a minimum 50 psi of oil pressure.

Frankly, your oil pressure looks fine, though a bit on the low side @ idle for a new engine. 30 psi minimum (fully warmed @ idle) is genereally what I've seen on a new/rebuilt engine. So I would monitor it to see if it gets worst.

But I have to agree with ede's comment about the lack of accuracy on the dash gauges. Also, your sensor might be a little weak and is the most common reason for erratic oil pressure readings. I would try changing that first, if you haven't already. And 2 sensors (or guages) don't necessarily read the same, even if new.

Biochem

My oil psi usually hangs around 40-50 psi especially if I am driving. At idle, it is about 30-40psi unless the temps get around 220F, then it goes way low to about 20psi at idle... 40psi while driving even when that hot.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock... all the suspension stuff... 9-bolt posi disk is in... K&N filter... 93 octane...

-=ICON Motorsports=-

Iroc_Z28

I have got around 6000-8000 miles on my 350 that i rebuilt and running 10/40w oil..... and it holds right at 60psi and even when engine is hot it still holds 50 or better...

BLACK Z

Does 5-30 and 10-30 have diffrent pressures? what about mobil one compared to regular oil, will it give diffrent readings?