I read that crank case vacuum is a good thing to a point.

Some say too much vacuum will pull oil away from the wrist pins, rod and main bearings.



This is what I’m thinking, on a wet sump motor the pump and oil reservoir are all

seeing the same pressure whether it is low or high, so what does it matter?



With a dry sump motor the oil reservoir is in ambient pressure.

I could see how it may affect rod and main oiling due to the pressure differential.



I don’t see how the wrist pin oiling could be effected because most are oiled

by splash oiling. however if the pins are using pressurized oiling they could be affected

like the rods and mains.

 

The advantage of crankcase vacuum is better ring sealing. On my last car with a NA motor anytime I was not on the throttle I ran about 10" Hg of vacuum. Unfortunately once you go WOT the blowby is quite good at gobbling up any vacuum you can throw at it. It takes a pretty good vacuum pump to do any good. Definitely no vane types. With FI it's even worse.