Oil Pressure Reading

[Blue Beard]

Any ideas on why the oil pressure pegs the needle on start up?

Using the stock gauges at the moment.

Just changed oil and filter, in case there was a possible problem. Was awful black.

After initial warm up it still shows about 3/4 on the gauge.

Don't know if the engine has had work on it or not.

Appears to be the stock 350 that was stock.......

[RUDEDAWG]

What weight oil did you use

[Blue Beard]

Don't know what was in it before the change.........

I use Valvoline 10-40 in everything I drive......

Before and after the oil change the readings are the same.........

[cableguy0]

u should be happy that u still got oil pressure that that good i dont exactly remember what pressure is when the stock guage is pegged but its good.

[crazy longhorn]

the stock guage is pinned on my 79 at about 55-60 psi. It stays pinned till it warms up, then comes back to about 3/4 guage @ idle(in park). The 355 has about 15,000 mi on it, & runs a hi press pump. It doesnt sound like you have any trouble....crazyL

[RUDEDAWG]

What weight oil did you use

[crazy longhorn]

Mine has 10/40 in it also.....crazyL

[RUDEDAWG]

Hmm. sounds like either you have a high volume pump or you are running too thick of oil. I have the same problem but I am running a high volume pump and 10w30, the average temp. right now is around 50 degrees where i live. i really dont think this is a problem.

[crazy longhorn]

No sir, its a high pressure pump(Z 28 replacement), temps are also a little cooler here in Ill. I have a high vol high pressure pump on the longhorn(melling 10555) that will pin a 80 psi guage when its cold......holds 40psi hot @ idle in park, & runs 70 psi @ 3000 rpms hot......crazyL

[ChevLoRay]

As long as you have 10 psi per 1000rpm's, you're doing good. Anything else is a "gimmee". My guess is that unless your oil pressure is so high that you are losing oil filters (which might happen with cheap ones), then you have no problem. If it makes you feel any better, my oil pressure is at the upper limit of the guage, when it is cold. As it warms up, it drops. When the engine is hot, at idle, the oil pressure is about 10psi. RPM's are at about 650, so I am okay.

If your oil pressure goes UP, when you let off of the gas, you are seeing an indicator of wear in the main bearings. Otherwise, drive it like it belongs to someone else.

[gman]

Well, thats a bit of a relief. I had the same question as Blue Beard. Mine goes to just past the 3/4 line at startup and gradually comes back down to a lit above half after warm up but I felt like I must have problems. High oil pressure is OK from what I've read here. My motor has high mileage but runs quite well. Oil isn't excessively dirty at changes. Using 10w-30. Does thicker or thinner oil help keep pressures up?

[crazy longhorn]

Gman, your pressure sound fine for a stocker with some miles on it. I run 20/50 in my 383 in the hot part of the season, & 10/40 in the cooler months . The pressure seems to run about 5 psi higher with 20/50 in the hot weather, as compaired to the 10/40. CrazyL

[stelth2002]

A stock calibrated gauge is suppose to reach 60 psi for everything except the big block. Big block equipped trucks came with an 80 psi gauge. As far as having that much oil pressure, the more the better to a point. It takes power to push all that oil thru and as people have said. 15 psi per 1k rpm is fine with conventional oil and 10 psi with syn. At least thats what i think

[72CustomCamper]

Just a some thoughts for everyone:

When your BODY has high blood pressure, it is a sign that your blood is too thick or there are potential clogs.

The variable displacement, gear type pumps in our engines work under the same principle.

1. Thicker oil gives higher pressure.
2. As the oil warms, it becomes less viscous, therefore thinner.
3. Your oil pressure should vary with RPM like stated above since the pump speed and flow rate is roughly proportional to crankshaft speed.
4. Nominal oil pressure for BB's is 40psi. It drops slightly at idle and should never really be above 60psi at any RPM.
5. An engine with considerable sludge buildup will indicate higher pressure than a clean one with the same pump.

The higher pressure is an indication that your pump is working properly but fighting harder to move the oil throughout the ports due to higher viscosity and/or flow barriers.

BOTTOM LINE:
As long as you have pressure, you are good to go.
(that is why there is no redline for oil pressure...)