View Single Post
  #23 (permalink)  
Old 09-05-2013, 04:44 AM
DanEC's Avatar
DanEC DanEC is offline
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2009
Location: Little Rock area, AR
Cobra Make, Engine: ERA Street Roadster #782 with 459 cu in FE KC engine, toploader, 3.31
Posts: 4,533
Not Ranked     
Default

Quote:
Originally Posted by car4jim View Post
There is another factor which I don't recall being discussed which is compression blow-by the piston rings building pressure in the crankcase. There needs to be sufficient ventilation from the crankcase or pressure will build. I have similar questions on how to structure the crankcase ventilation system. I have a Keithcraft FE stroked crate engine that has a hose from the drivers valve cover to air cleaner carb intake, a puke tank with road draft and connection to the rear intake manifold and crank case and a vented oil fill cap and I still blew the oil fill cap off the breather at Fontana this summer. It seems my engine needs more crankcase ventilation area. Any idea how much bypass flow is created by the oil rings at 4000 RPM, etc? What is a acceptable positive crankcase pressure?
I think I would talk to Keith's shop about that. That sounds like more positive crankcase pressure than you should have from a custom built motor. I assume the oil fill cap/breather had good tension on the retainer clip?
Reply With Quote