The foaming oil is coming from the return line from the pump. The movement of air from the big pistons moving up and down and engine blow by are creating foam in the oil and that internal pressure is trying to push up into the throttle body from the cam chest. With no tank pressure the cam chest vent is devoid of oil.
The crank case breather has no oil spitting out of it.
Last edited by LightSpeed; 21/04/20 11:09 AM.
