Re: Oil Line Restrictor?

Posted by Owen_Dyneto On 2010/11/16 9:04:47

JW, sounds like you have a nice, tight engine; a pressure of 40 psi at hot idle is certainly fine. With hot, idling pressure that good the reason you don't hit 50 at road speed is probably a bit of fatigue of the spring in the oil pump relief valve. If you wish to bother for peace of mind or whatever, you can almost certainly achieve the spec. 50 psi at road speed by adding the thinnest of shims to the spring in the oil pump relief valve.

The higher pressure spec for the 356 engine is no doubt because you have 4 more main bearings with their associated clearances which allow additional pressure loss.

As to the filter restrictor, it really shouldn't make any difference to the engine operating oil pressure if it's in the tee before the filter supply line, in the fitting at the filter inlet, or in the filter outlet (internal post) though placing it on the supply side would seem more logical as it would maintain the pressure differential across the filer media, with a restrictor on the outlet wouldn't do.