Kevin Johnson wrote: ↑Wed Dec 04, 2019 12:47 pmA SBC and SBM can have the sump reservoir in different locations. Many SBMs have a front sump and during drag racing with a stock type pan it is more likely that the pickup opening will vortex to the surface and/or that the oil displaced to the rear will be churned by the rotating assembly. During vehicle/motor development with parking or driving on grades this will be noted as well. Yes, I know about front sump Chevy II/Nova oil pans.
The additional air that is whipped into the oil by the rotating assembly cannot all be dissolved by the pump so there are free air bubbles present. A bubble filled fluid being accelerated by the oil passage will have conflicting phase flow paths determined by density. This will delay transit in the passage and could require additional degrees of advance to allow for the outer phase (oil) to successfully reach the rod journal. That would be determined by empirical testing under the expected operating conditions. Different companies or even divisions within the same company will generate different solutions.
If you alter the conditions that the vehicle/engine operates under then changes could be needed. Obviously, successful changes have been found by authors in this thread.
You're correct Kevin and I should have mentioned that too. If I am building something that is capable of making 2 HP/CID at 8000 plus it always always gets a rear sump pan or a box pan with the biggest kick out I can get in the car on it.
Also the gerotor pump requires a significantly larger inlet than a spur gear pump. On my best stuff I had a dual pick up with the main pick up at 1 inch and the secondary pick up at number 10 line.
And all that and still it would nick a Rod bearing in 3-4 passes and if you didn't catch it, the 5/6 pass was kicking the Rod out.