onegreedy

ok i have finally been able to drive my 67 coupe today, my question is when it first starts up i have 42-43 idling lbs of oil pressure, after it warms up it drops down to 25 lbs idleing, when i am driving it goes up to 50 lbs.

is 20 lbs to low,

it is a 351 w

Gun Jam

That should be fine a bit lower than normal but should still be plenty . What oil are use using? 10-40 works well in mine

KBunny

I thought chevy was the only one that did varying oil pressure... my 66 289 stays steady at... ? something... but only varies from low to normal when I am low on oil.

mjr46

no your fine....as for the varying oil pressure my 66 reads close to 50 cold and at idle hot drops to 20-25......but then again it'll depend on if your using a factory gauge or a aftermarket mechanical one...like I use ..in the long run it's the better choice = more accurate

Gun Jam

i have a mechanical oil gauge. i get about 70lbs warm above 10mph and about 35lbs warm at idle add 10 to 15lbs when cold

KBunny

so is there something wrong with my gauge (electrical)/engine if my pressure doesn't change weather cold or hot or idle or high rpm?

mjr46

that's what I am wondering??? cause even when I had my stock gauge used it fluctuated..I just never liked the L/H meant nothing to me...I like actual numbers...your sending unit may be bad...and or a gauge issue

Gun Jam

No
there is nothing wrong with it...it just never worked right from day one. Most electrical gauges work about like that they just aren't as sensitive as a mechanical gauge to pressure change. My stock electric gauge works just about like yours.

You can check to make sure its not leaking oil from the sending unit that would prove its bad you could try a new sending unit but probably wont be impressed with the results

boogerschnot

I just figured out that my freshly rebuild 351w is getting 50 at idle, 35 in gear,, and up to 65 when at speed.. I run 10w-40 to start with

Colorado_Mustang

Oil pressure is usually spec'd at 2000 rpm. The general rule of thumb is to have about 10psi for every 1000 rpm the engine is intended to run. I run 50psi at idle, with a pressure relief set to 80psi, which kicks in at 2500 rpm, or when cold.

Any guage with real numbers should indicate a fluctuation in oil pressure. Gauges with "NORMAL" written on them likely won't show these fluctuations due to the design of the gauge (and to keep the uninformed from taking their cars in too often).