Has anyone tried to lower the crankcase pressure? The timed breather through the crank or balancer is not enough. I only get a small amount of air out of the breather hose. The vent on the valve cover doesn't vent to atmosphere.

My motor has 1.5% leakdown. At idle, the crankcase has significant pressure. If you unscrew a plug on the stator cover, a lot of pressure flows out at idle. Same for the plug behind the clutch area.

The motor has no PCV valves.

When I installed my new turbo that uses the high pressure engine oil supply, I had to install a scavenge pump to return oil to the reservoir tank because the crankcase pressure was too high to gravity feed the oil back into the crankcase.

I've heard of using the engine's vacuum at idle to draw out crankcase pressure. Don't think it would work with a turbo since theree is no vacuum under boost.

 

go to a local salvage yard and get a 12 volt electric smog pump to use as a crankcase evac system i have used this method many times and it works great they are very small and you can use a switch to run all the time or just when you want it also scooby it is worth around 10% hp at high rpms try it new camaros and ta have one that is where i get them but any auto with a electric vacum pump will work.[img]i/expressions/face-icon-small-smile.gif[/img]

 

On automotive engines there are two hoses for crankcase evac. One as you mentioned between the throttle body and engine for idle and part throttle (pcv) and the other in the air cleaner for WOT. At WOT there is vacuum between the filter and the throttle body created by air velocity so it make a very good source for evac...as long as you have room to install a hose there.

 

[img]i/expressions/face-icon-small-confused.gif[/img] This is going to take a while to figure out!!!

 

This is a very interesting topic. I've got a 465EX that is not stroked..it has a 92mm piston and I have not done anything with the crankcase vents. The stock piston is 85mm and going up to a 92mm has to be creating alot more pressure in the crankcase which will make me lose hp. SAMCOEDS did you do anything to your vents on your 465?

JMiller

 

I USE A K&N small filter on top and hook the vacum pump to the lower where the hose was i only run it when racing at high revs.