Blowby Breather
Well the old girl is getting to the point where she has a little blowby. I have a tiny amount of oil that likes to leak out of my brand new valve cover gaskets and sit on the head. I've heard that blowby should be vented from the highest part of the engine, dont know how true that is but it makes since. Anyway my plan is to drill and tap a couple valve covers (2&5) and set them up with a couple breathers. A buddy of mine gave me a fitting that he used for the filter and it works perfect. I'd like to know your thoughts on blowby and the proper way to vent it. Thanks for any input fellas.
Here's the parts
Here's the parts
Last edited by 901stgen; Jun 10, 2011 at 03:41 AM.
There's a breather tube on the drivers side of your block. That's where blow by gets vented. But those vents on the valve covers probably work more efficiently, as well as look trick as all get out! 

Good possibility it'd clog. They were designed for gas jobs, with the use of a PCV valve the only thing that should make it's way thru that filter is fresh air. Diesels how ever dont "circulate" air thru the crankcase in tue same manner. There will be an oily steam vented thru that filter. How long it'll take to clog... Who knows. Clean it and or replace it periodically; it isn't like they're horribly expensive.
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On my detroit in my freightliner the blowby pipe come out of the valve cover up high on the side but it is just a pipe going down the side of the engine the filter will clog eventually pittsburgh power makes a nice little catch can for big trucks you might look at it to get some ideas
I feel like that will lead to ton of oil mist all over the engine. Could you just feed a pipe into the intake or air inlet hose that would use that oil mist during combustion like a gas engine? Or would that runaway?
Ive seen this done on many trucks and doesn't leave any mist or oil residue.... Its not like this fitting is the size of the valve cover. Its only like half an inch big. Just simply vents the excess pressure under the valve covers caused by higher than normal blowby, simply put. Ill post up some pictures of how to do it and how it turns out. Main thing is to make sure its not in the way of the rocker arms.


