oil psi

[392hemix]

I have a 440 with a high volume mopar performannce oil pump. they come factory pre set to 70psi. when i dynoed the engine it ran perfect, to a tune of 450hp 536ft lbs, and is a very stout engine, but when i put it in the car and got it started, the oil psi gauge became sparatic and bounced thetn it smoothed out. now it runs @ 80-85 psi @ idel, and goes right up to 100 when you get on it. Could the plunger just be hanging up? has anyone had this issue? and has anyone used the adjustable oil regulator that replace the plug that holds the spring and plunger in? just trying to figure out something to fix this issue. 100psi is just way to much psi

 

[Hemi Time]

Is that psi cold or hot both my big blocks have 90 psi cold just above idle until they warm up and 70-80 psi @ 3000 rpm hot .Have you cut the oil filter apart for inspection since you dyno'd engine just for curiositys sake?

 

[392hemix]

The psi is is 95psi cold and then when it warms up its 85psi, but as soon as you touch the throttle, its up to 95psi and if you give it some more fuel under load it hits 100psi. in my opinion and from what i have read, you "Need 20psi @idel and 10psi per 1000rpm. anymore is just wasted power. i understand that most pumps are pre set to idel around 70psi. which is fine, its not like im trying to get every last bit of power. i just want it to apeate @ a resonable psi, and be reliable.


I have not cut the oil filter open yet. I know there was a lttle bit of silver in the oil, its brad pen, and i dumped it into a clean pan and inspected it. I should cut the filter just for fun and see if theres any large metal in there that could have bung up my oil pump, or give me reason for concern.

 

[Pistol Pete]

First thing I'd do is try a different mechanical gauge just to verify those readings as accurate.

 

[Hemi Time]

392 I have a friend who is a genius at performance mopar engines and all engines in general, and with his own engine a high performance 440 stroker he had the same problem your having.He had 100 psi when you rev it up because he modified the oiling system to much then he had to put a restrictor in I will ask him this week how he fixed it and try to get back to you.But I remember him saying it was tolerable and he could of left it at that pressure.
My big block idles at min 40psi hot and goes up to 90 psi if you rev it up and thats tolerable.

 

[392hemix]

Thank you for your time Hemi time, any help will be greaatly apreciated. I have been waiting all summer to drive this thing.

 

[Hemi Time]

392 I asked my friendly neighbourhood mopar engine rebuilder and he said to lower oil pressure simply shorten the spring on the valve in the pump.......try that!!!!!!!!!!!

let us know how you go!!!!

 

[392hemix]

Ok, i will do it as soon as i figure out my other plug fouling issue. Thanks for the information, i will let you know what becomes of it

 

[Meep-Meep]

My 383 used to peg the gauge at over 100 PSI and the lowest I saw it go was 95 hot at idle. I put about 5000 miles on it and tore it down and everything was fine. I used the exact same pump without doing anything to it and put it on my 426 Max Wedge and it ran 70 PSI at idle hot. The 426 had (according to plastigauge) .006" rod and main clearance. It was so loose I had to go to the blue stuff because the green didn't crush at all!!

If you get the same result with different gauges I'd suspect the plunger is hanging up in the bore or the spring is coil binding somehow.

 

[392hemix]

Ya, i still have not had time to look @ it, I know that high oil psi is not really going to hurt the internals of the engine, but it does rob hp, and will wear out the pump faster. I do imagine, that the plunger or the spring is binding some way that is distorting the oil psi. Im just mad that its not running good, and the hp numbers are down....o-well i guess another summer with out driving the car

 

[392hemix]

Got it under control switched out the plunger spring to a weaker one and now its right were i want it