Using Crankcase Pressure for forced induction!

[nickoroniper]

Im running 2.3 roller motor, carb(2100), duraspark. Ive used the same set up for 15yrs.(different motors) At somepoint, my pcv valve hose was moved to a spacer under the carb. I recently rebuilt the carb after 10yrs of questionable reliability, having trouble adjusting my timing, idle, mixture for all around performance. Get her to idle nice, wont matain cruise rpm, get cruising adj. wont idle. I decided to unhook the pcv from the intake, thinking my sucking (varible) air from crankcase. Got it tuned in, about 10 minutes, blew oil out of the front of the pan, dipstick, and valve cover. alot of oil. hooked the crankcase back to constant vaccum, no more leaking. I have absolutly no smoke, not even shift smoke. Burns no oil, at all. runs out awesome. My theory, is with rings or valves I would think I would be burning oil, and or smoking. After 6 beers tonight, I had a thought, could I have possiblably blew a head gasket between cylinder and oil jacket??? I have had one blow combustion out the front, and even the awesome waterjacket/combustion one. Just want to know what you think before I proceed. thanks

 

[Hahnsb2]

Vacuum in the crank case is said to seal rings better. Your engine probably has a lot of blow-by. A compression test and leakdown test would be most helpful.

 

[nickoroniper]

Thanks for your reply. I just read a publication on crankcase vaccum, says its widely used in racing applications, guess it pulls rings tight against bore, and reduces restriction on pistons, gaining power 15+hp. Never knew! Also says it keeps oil away from hard to reach places, that part is not so good. so I believe I will be replacing the best motor Ive ever had in it. All good things come to an end.