Crankcase - Pressure & Vacuum

[Billman]

Finally got the truck out today for some testing.

I found that the crankcase has the ability to make 1-2psi when viewed on a gauge.

I am trying to eliminate the CDR, and re-route the hose into the exhaust. Similar to the EVAC set-ups we run on the Racecars. Vacuum in the Crankcase can make Big Power.

I don't necessarily want a tremendous amount of vacuum on my 6.5, but I figured a little would be better than none and I'd get the added bonus of routing hot fumes out the tailpipe.

With a nipple welded into the downpipe and a checkvalve screwed onto it, No Vacuum was achieved. As a matter of fact, that's where I found out the crankcase built 2psi. Suspecting the checkvalve wasn't helping me, I removed it and hooked the hose directly to the nipple in the DP. Took the truck out again, unloaded, 15psi boost, with only gauge hooked up, I saw 1 in vacuum. Then reconnected hose to breather on valve cover that replaced CDR. Roadtested again. No pressure - No vacuum. Not bad I figured.

Maybe helped the crankcase a little while re-routing hot fumes into exhaust.

[kowsoc]

Very interesting! Pressure in the crankcase will only cause gaskets and seals to seep and make a mess. I wonder if the CDR is bad....usually the blow-by just gets put into the intake duct where it makes an oily mess. Better place to dump would be the exhaust.....not if your concerned about emmissions though. ;)

[eracers999]

This system needs to be perfected, we will see what diference the 4 in pipe made soon.

Thanks!

Kent

[DBlake]

My only concern would be eliminating the CDR. It also acts as an oil separator, letting any oil collected drain back into the valve cover. It seems you might seriously increase your oil comsumption. Every diesel I have had experience with always had some sort of oil separator/return scheme for blowby, which makes me think that oil loss without it may be significant.