View Full Version : crankcase ventilation


railing68
Jul 3rd, 02, 10:53 PM
I can't run a pcv due low idle vacuum, 7hg at 1100, yes the cam is big solid in sbc. Evac systems using the exhaust only pull oil into the exhaust. I do have 2 large Moroso breathers installed with baffles in Moroso tall valve covers. I've heard of using smog pumps to evac the crankcase, but this seems limited with the addition of another belt. I recently saw a mech fuel pump used on the pull side connected to a breather. Would an elec work in the same manner?

stingr69
Jul 4th, 02, 05:09 AM
You might try the Smokey Yunick method. He used the holes in the valve covers and tied them together in the middle and had a puke tank mounted in the wiper area with 2 breather caps. Better than the alternatives I guess.

-Mark.

lnjstreetrods
Jul 5th, 02, 10:17 AM
If you have good baffels inside the valve covers you should not pull oil through the headders. When I use the exhaust system to evacuate the crank case, I cut a 1/2 inch pipe nipple @ 45* then weld it on the headder near the collector area. I think you have done all of this, but the smog check valves then screw on the pipe nipples. This keeps exhaust out of the engine at idle, and gives some restriction to the flow at WOT. Most engines will have about 18" vacuum on the crank case at WOT set up this way.

Larry www.lnjstreetrods.com (http://www.lnjstreetrods.com)

railing68
Jul 5th, 02, 05:37 PM
I responded at the lnjstreetrods website about possibly purchasing the hardware for an evac system. Also how much vacuum is needed for pwr brakes, they used to work fine but I remember having an additional 2" for a total of 9, they do still seem to work but not as well. Anyway I am considering a vacuum reservior, but how far can it be mounted from the booster or other accessories, and could the evac system be junctioned off to help with such acessories such as brakes and accuators for headlight doors.

lnjstreetrods
Jul 5th, 02, 07:54 PM
The extra vacuum canister will help but not fix the problem. The thing is when you get down slow and slow idle there is not enough vacuum for repeated brake pedal movements. There is no vacuum to be had from any where at that point. Distance on the extra vac storage should not matter. There are cars out there with belt driven vac pumps but like you have already said wow another belt driven something else. I will respond from my shop on the lnj question. That email goes there.

Thanks, Larry www.lnjstreetrods.com (http://www.lnjstreetrods.com)