Oil pressure

[steve remick]

1983. Is 30psi normal at highway speeds for a 305cu in.

[mfg]

Yes, stock 305 Chevy V8's do not generate very high oil pressure.....but to really know what your oil pressure is, hook up a mechanical gauge directly to the engine.

The all-electric, factory oil pressure gauges aren't known for their accuracy!

[Avanti83]

If you are nervous check the actual pressure with another gauge but while it's lower than my SBC's run it's within the generally acceptable 10 PSI per 1000 RPM as I suspect you are under 2500 RPMs with an overdrive tranny. If correct, it probably represents some wear inside the engine if you are using the usual 10W30/40 oil at 185 - 190 deg. I wouldn't get excited unless you are running higher viscosity oil.

[steve remick]

Thanks guys, I'm not concerned with 42,000 actual miles on it. It has the 200 R4 tranny and yes it runs at 70 mph, 2300 rpm.

It's just that my 64 R1 289 runs 80 cold and 60 warmed up.

[Buzzard]

On the IDYSD weekend we drove our '83, 305, 25,000 original mile Avanti. At one point I almost had heart failure as I noted the oil pressure even lower than normal (35-40psi). I believe it was showing approx 20 psi at highway speed (2200 rpm). As no noises occurred I thought it to be a gauge or sender malfunction. I ended up tapping heavily on the gauge itself and presto, back up to 40. Maybe other units are lazy like this one?

Bill

[dynolou2]

One thing that I found on my 1985 was an incorrect sending unit, gauge is a 60 psi unit sending unit was an 80 psi unit. After several tries with S&W, called Dan Booth and got the correct one. The problem with the S&W unit was the height, it was too tall. My 75K 1985 shows 30 psi at freeway speeds, about 1800 rpm at 60. Lou Cote

[wildfelr]

RQB3263....My 305 runs max 35PSI (about 20 at idle) WITH 104K MILES....i have recently switched oil to Shell Rotella T 15w40...diesel oil...The diesel oils have the anti-wear ingredients legislated out of auto oil...thanks to our unelected wizards at the EPA...I suggest you switch also....BILL RQB3263

[wildfelr]

RQB3263....The too tall sending unit problem is very easily corrected by installation of a pipe thread adapter to AN-4 and use a stainless braided brake flex line about 12 inch long adapted to your sending unit and secured up near the back of your brake booster....Ive done this on every Chevy hot rod ive owned just for convenience sake....its easy and its cheap...BILL RQB3263