Mark T.

I've got a RX4 n/a 13b and want to raise the oil pressure by shimming the old style rear regulator. I'm told the car used to run around 60 psi. I've just bridge ported and rebuilt the engine with new bearings and oil squirters replaced with #200 jets. Although it will be used for racing, I don't expect the owner to be pulling massive revs. Any suggestions on how much to shim the regulator?

j9fd3s

i think id take the easy way, and get an FD regulator, its $23 here

mazdaspeed7

I second that. Ive shimmed a rear regulator before, and with the price of the FD one so low, it just isnt worth it. FD is around 100 psi, but I doubt you will see that much before 5-6k.

BDC

+1. Use a 3rd gen regulator.



B

Jeff20B

I have the old adjustable type in my '74 engine. I shimmed it with washers up to .140". It's just breaking in so the bearings are still tight, but it gets 100 PSI cold and 50 PSI warm/hot at idle. 20w50 Castrol GTX is what's currently in it.