[jonmachota78]

Ive got an .060" hardened washer in my 60lb pump and it give me 60lbs now lol!

[track73]

I'm curious. If you don't rev the engine passed 6000 rpm why would you need 70 psi oil pressure? I have seen cams where the distributor gear was worn. I assumed it was because of to much oil pressure. (solid lifter stock car engines). Oil pumps take HP to run. NASCAR guys turn it down when qualifying. And, restricted crate engines don't run high oil pressures.

[steve25]

NASCAR motors don't run 3.250" mains like a 421/428 and 455 that need more then 10 psi per every 1000 rpm!

[AG]

The pump is going into a 3.25" main motor that will shift at 6000 rpm, I want to run 70 psi. I don't think it will have any detrimental effects on anything.

[HWYSTR455]

The 10 psi per 1000 RPM is a general rule of thumb, many argue you can have less. I have seen race engines live for a long time with huge (in comparison) bearing clearances, and near 0 psi at idle, being spun well over 6000 RPM.

Me, personally, get nervous with less than 10 psi at idle. But if the engine has been together for a while and running fine, I live with the nervousness.

You can adjust psi with clearances and oil weight, to some degree, but if you drive in colder seasons, you have to be careful. Between 10-30, straight 30, 10-40, and 20-50, there's only a couple psi between each step when hot. I would guess that between the two extremes, there's around 10 psi difference.

Dizzy gears wear for different reasons, and doubt 20 psi is going to make that much of a difference. Topic has been discussed, can search it.

Clearances over 25, I've heard some builders use 80 psi pumps, Butler for example, and some strokers Spotts builds. Not sure anyone would ever notice, or be able to measure the amount of power diff between running a 60 or 80 pump.

Shimming. Pumps are only close to their' rated psi anyway, most of the 60 psi pumps I've seen are like 5 - 10 psi below that, in use. If you have larger clearances, shimming does give you a little more, and a little more piece of mind. How much to shim? You don't have to over-engineer it. Any will give you more, and obviously you don't want coil bind. But I have heard .060 - .100 is fine, about the thickness of hardened washers.

When I freshened my 461, which originally had a 80 pump, I changed to a 60, shimmed it, and the washer used was about .070. I could look up the clearances, and provide psi with the engine at temp, if someone reminds me!

So for the ramble! Thinking out loud here...

.

[Formulas]

I've been wondering what effect the smaller relief ball would have in a 80psi. Pump

[Squidward]

Originally Posted by RA462

I use a 5/16 lock washer that I flatten out. Usually gives me about 70 psi in a 60 pound pump. You might have to grind a slight amount off the OD of the washer to get it to fit inside the spring cap.

I think I had to file the outside of my washer, too.