Originally Posted by tony xa
Please any advise on oil restictions for my engine and if they are needed
My engine builder asked if I wanted to do this to keep the oil up top . He also said something about running a line from oil presure switch back to the front of the engine. but can remember someone saying it isn't advised .
engine is 393 clev solid cam hv oil pump 7 litre energy sump.
You add the oil restriction to keep the oil out of the top end and in the pan where it can be fed to the mains and rods. There are several schools of thought on how to "fix" the Cleveland oiling system. They are based on engine performance/usage and budget.
The easiest way to spin to 7500-ish is to use mechanical flat or roller tappets and add restrictors to the cam bearings and to the right side lifter galley. You can't restrict the left side galley without blocking flow to the rear (#5) main.
This photo shows the basics of the Cleveland oiling system. Notice how the entire right side lifter galley is fed from the rear main? You can restrict flow to the right side, but not (as easily) the left side.
With restrictors to the cam bearings and the right side lifter galley, you're arguably fine to about 8000 RPM.
High RPM than that requires bushing all of the lifter bores, an $800 (US) process here. For that kind of money, an SVO block starts looking rather attractive.
With all of the mods, external oiling and dry sump, you can run a short stroke Cleveland to 10,000+ RPM. But anyone considering it today would be far better off buying an SVO/Dart or Fontana block.