Originally Posted by Cole2534

16 - .040" holes is only .020 sq in. That's not much flow area. Like about a single 5/32" hole.

Originally Posted by Full Force

what main clearence you running?

Originally Posted by FIXX

tim i reallly dont remember ,,i built the engine way back in 1997 and havny touched it..it does have high dollar goodies in it..i spent 6500 just on the short block...0003 sounds rite..i like to run a little loose clearances,when the engine get hot you know how sh!t can expand..

Originally Posted by Gimme Fuel

So what is the main issue with running the Melling Anti-Cavitation pump that you have found? I installed a SP/HV version on my 540. Seems I have plenty of oil volume, but the pressure is a little low for my liking by the time it goes through the external system, so I was going to put the high pressure spring in. Electronic gauge says 45 PSI hot (20 idle) at filter boss port and cheapie mechanical gauge at front oil galley port says 50 psi hot. Oil pressure maxes out at 3000 rpm and does not climb as I increase rpm. I selected the anti cav pump because I will be turning a few more RPM than most (6300 peak/6500 limiter).

Originally Posted by lil red

Not sure about you, but i don't warm the oil in boats with a heating element on the pan, fire it up let it idle, go out through the no wake zone , and then when the oil temp starts to come up, bring it up on plane and run it. Then come off plane and idle through the harbor to your destination. Way too much time to be staring at a gauge showing 10 lbs or less oil pressure for me.
I will say that engine had tight bearing clearances, and the bearings were in very good shape.

Originally Posted by MER Performance

Oil pressure has always; seemed to be open for discussion. If testing a pump, with a gauge in a bath of oil gives you a reading of 65-70 psi, you have to remember that is at the pump. The reading say at the upper oil galley at top of block will be slightly lower. This is going to come from a decrease in volume, which results in lower pressure.
If you speak with a crankshaft manufacturer or one of the engineers, they will still go by the old school method of 10 psi for every 1000 rpm. When you look at the engineering aspect from the bearing manufacturer, the theory changes. The oil and bearing along with the location and design of the crankshafts oil galley, are going to determine the hydrodynamic wedge created between the crank journal and bearing surface. Oil temperature, bearing clearance, and the straightness of the bearing bore ( Main bore straightness in block ) are going to determine how straight the crank rides on bearing. The deflection and rpm of the engine are other factors to consider when setting up bearing clearances along with the viscosity of the oil you will be using.
I have run 54 psi oil pressure in BBC at 6000 rpm, using a Schumann oil pump and having the relief set at 75 psi at the pump incorporating a external .500 relief check ball. That is with 50 wt Redline Synthetic Racing oil, now keep in mind the mains are at .0032, rods at .0026. If I was to tighten the mains up about .0005, that would have a great affect on the oil pressure over all. The oil temp once above 140 will drastically change oil pressure only due to it's flow capabilities, oil must flow and flush the bearing in order to not overheat or scuff the bearing or crank.
Running a high oil pressure not only creates parasitic drag, it excessively loads the distributor gear, cam gear, and shaft housing and bearings in the distributor. High oil pressure also creates spark-scatter, in extreme cases also add the load on the timing chain.
I'm sure all of you know; the oil has to have ample pressure for supplying the mains, rods, cam and lifters, with it's final destination of lubricating the rocker arms and cooling the valve springs. Sucking the oil pan dry and filling the top end of the engine with oil would mean the oil isn't returning fast enough or the oil pan is way too small. Crankshaft windage and pan design are also going to greatly affect oil return and if it is aerated, causing failure of bearings with air pockets mixed in pressurized oil.
So don't be set on having high oil pressure as your safety factor in a build. You could have high pressure and still wipe your bearings out or you could have lower pressure and have like new bearings the next time you freshen up the engine.

Originally Posted by Borgie

Here is a link for Schumann oil pumps. They have quite a few features melling does not. The most important one being an external bypass vs reverting the bled off oil backwards down the pickup. Mark Rinda uses quite a few of these pumps. He recommended I give one a try, so I bought the 140HV series. Specifically states it can be used with external coolers and spring oilers. Ships with a rated pressure of 72psi, however you can increase pressure to suite your needs with a spring/shim kit that Vern sends with the pump. Also had a provision for my Dan Olson oil pickup, and a copper gasket for the sealing surface where the pump mates to the rear main cap.


http://www.schumannsdynamicperforman...-oil-pump.html