Rebuilt my 455 and have put a mechanical oil pressure gauge on. When the car gets warm 200 deg the oil pressure seems to drop significantly. Of course this has me worried but he motor seems to be running just fine ,no lifter noise etc. Have about 3000 on rebuild. What does the factory oil pressure suppose to be at idle? I have heard they run a little low. I have headers which I am sure does not help oil viscosity. Have 7 quart oil pan and high volumn pump. wondering if i should switch from a Mechanical to a electric oil pressure gauge? Any thoughts appreciated.

 

Tim, I don't know if the factory ever rated oil psi at idle, so I can't answer that for sure. I would think that 20psi and up would be good at idle....but what idle speed.?

There's an old saying that goes... 10 pounds for every on one thousand rpm was acceptable. We could probably do better than that in order to call it good.

I might add that, I don't see temps of 200 much in my car, unless I'm tinkering with it in the driveway. Its allmost allways 190. Hey...but my car has whole lot more miles.

I would want to check it with another gauge too. Just to be curious.

 

You don't say what your at idle and running down the road pressures are. Hard to make a comment of yours.

My 455 is 25 lbs at idle which is 800 rpm, at higher rpm it runs at 50 lbs

 

What weight oil are you using? I use 20-50,or 15-40 deisel. If you are using 10-30,it will be low when hot.

 

I use mobil 1 15-50, a 7 qt pan, and HV melling pump.
42psi red hot at 1000rpm idle, and 65 at full throttle.
rod clearances are between .0025 and .0029, and mains are between .0033 and .0038
I elongated the main bearing oiling holes.

Hope this helps.

 

First start today in MI. Nice day. Curent oil presure gauge showed 40 psi at idle after sitting since last year. lifters pumped up fine. No knocks. I will try an electronic oil pressure gauge before I proceed on to something more elaborate. I run 20 /50 Brad penn. Usually run about 190 temp on average day.