SBC oil pump pressure

[SS4REAL]

I've got a brand new oil pump/pickup assmebly from Moroso.
PN 22134. The pump is stamped M55HV.
This is the high volume pump for the 8 1/4" pans.
My question: what oil pressure should I expect?
It has a Pink/Orangeish color spring installed in it. It also
has a Black/plain steel colored spring in the box with
a new retaining pin.
Question is: which one is the "high"/or "low" pressure spring?
And: what pressure could I expect on either with a well bulit
performance small block ?? Maybe a general range?

[Scott Liggett]

Re: SBC oil pump pressure

I have the same pump in my 383. It used to idle about 22-25 lbs and run at 50 pounds at cruising speed. Now, it idles at 19-20 and runs at 45 lbs at cruising since the cam change. I think I may have scratched a cam bearing during the change causing the slightly lower pressure. It still has more 50 lbs at 5000 rpm.


I think the spring only changes the bypass pressure. Increasing it.

http://data.melling.com/TECHtips.php#qc

[JeffMcKC]

Re: SBC oil pump pressure

Yep, the spring changes the by-pass pressure I for one would stay away from the 55 pump they changed the casting now they break off a lot. I would not think the oil pressure would change from a small nick in a cam bearing they dont need much for cam bearings to work they are restricted by a lot and it should not show up going down the road.