Oil Pressure

[Rick Parker]

Joe:

There have been many discussions regarding proper oil pressures for all the various engines we use and it is a very opininated subject, with a lot of good information exchanged. Here is my 2 cents worth:

If you are using looser than standard bearing clearances, or have increased the connecting rod side clearances and are using a standard volume oil pump the pressures you describe are probable. The pump DOESN'T create the pressure directly, it only creates the flow/volume of oil available to the system. The bearing clearances and connecting rod side clearances create the path for INTERNAL LEAKAGE which in turn causes pressure to be created because of the restriction. It is the amount of this LEAKAGE that dictates the potential pressure for a given volume. (increase the clearances and the pressure drops) The bypass spring (in the mp or block) sets the maximum pressure that can be reached before bypass ONLY IF there is enough volume/flow available. If you are adding a cooler & related lines you will experience a further drop in pressure unless a HV pump is added. Fluid dynamics will cause the drop.

The 351 Std Windsor pump internals are the same as the HV set used for the 289/302 ie: They move the same amount of oil.

My pressures are as follows with a cooler & -10 hoses.

289 on steroids
Remote Filter & cooler with -10 lines
Melling HV pump with internals coated
80# at cold startup idle (Bypass spring set at 80#)
At operating temp 70# at 3000 RPM cruise and 35-40# at 850-900 RPM idle.
No problems ever with distributor gear. I burnished the cam gear and distributor gear before assembly.
10-40 Kendall GT-1 (Best non foaming oil I have found)

Rick