So I am being told by another engine builder...

[bigmanjbmopar]

That a solution that works to help relieve pressure build up in the engine - i.e. oil leaks due to high pressure is to make a 1/2" tube that welds into the collector(if you have headers) that has a beveled hole cut in it so that exhaust gases create a vacuum that will help draw oil fume build up out the exhaust by plumbing a tube from there to a breather in the valve cover?

Anyone ever do this or heard of it? I do experience some high pressure in my 493 and I attribute some oil leaking at intake edges and pan gaskets etc to the pressure build up. I run at 80 psi during warm up and usually around 40 60 at idle to cruise.

Just wondering if that is a fix or?

 

[69hemibeep]

Most racers use that system but I haven't looked for it on the street. Emissions wise I'm sure its a no no.

 

[bigmanjbmopar]

I not really thinking of cutting and welding a hole in my headers but was talking about the pressure issue and this came up. Never heard of that before and wonder if there is something already made? My first reaction was to bolt in a pre made plate between the collector and pipes that has a fitting built in. Started me thinking on a new item to market lol

 

[abodybill]

I have 4 breathers in my valve covers.

2 in each and know problems so far but,it's a built SB.

Had this setup for over 12 years. :yesnod:

 

[69hemibeep]

Just got to thinking about this. Any back pressure caused by an exhaust system would change how it works and possibly add pressure to the crank case. How many breathers are on the engine now?

 

[bigmanjbmopar]

Well I forgot to mention that it would have to have a check valve like in a smog set up to prevent the exhaust back in and create a vacuum. but after thinking more about it don't think it would be needed even with high oil pressure and I am using a pcv on one side to the carb and a open breather on the other side. So unless the pcv and or breather is not working it should be fine.

 

[george68hemirr]

you can buy the whole system from jegs.com or summit racing.com.....its called a evec system .....beveled tube with check valve....hose and breathers......you cannot use this on the street since its just fot wide open throttle....if you do use it your valley pan under your intake will look like you just made some popcorn.....your engine will not breath enough so internal gasses cannot escape fast enough......go with bigger breathers or a vacumn pump
hope this helps

 

[moparchris]

The evac system you are describing only work open header or with really big exhaust. It works on a pressure differential and if you get more pressure in the exhaust than what in your crank case it wont evac. The reason you have so much crank case pressure is because you are getting combustion pressure escaping by the rings. Either from worn out rings, loose piston to wall tolerances, large ring end gaps, or a hole in a piston. When someone builds an engine its critical to get your tolerances perfect or stuff like this will rear its ugly head. Oil pressure really has nothing to do with excessive crank case pressure.

 

[droptop]

The evac system you are describing only work open header or with really big exhaust. It works on a pressure differential and if you get more pressure in the exhaust than what in your crank case it wont evac. The reason you have so much crank case pressure is because you are getting combustion pressure escaping by the rings. Either from worn out rings, loose piston to wall tolerances, large ring end gaps, or a hole in a piston. When someone builds an engine its critical to get your tolerances perfect or stuff like this will rear its ugly head. Oil pressure really has nothing to do with excessive crank case pressure.

:yeathat: Do a compression test, and a leak down test. Sounds like excessive blow by to me.

 

[george68hemirr]

The evac system you are describing only work open header or with really big exhaust. It works on a pressure differential and if you get more pressure in the exhaust than what in your crank case it wont evac. The reason you have so much crank case pressure is because you are getting combustion pressure escaping by the rings. Either from worn out rings, loose piston to wall tolerances, large ring end gaps, or a hole in a piston. When someone builds an engine its critical to get your tolerances perfect or stuff like this will rear its ugly head. Oil pressure really has nothing to do with excessive crank case pressure.

thanks chris ....i forgot to tell him also about open headers.....and what you said

 

[moparchris]

The evac system you are describing only work open header or with really big exhaust. It works on a pressure differential and if you get more pressure in the exhaust than what in your crank case it wont evac. The reason you have so much crank case pressure is because you are getting combustion pressure escaping by the rings. Either from worn out rings, loose piston to wall tolerances, large ring end gaps, or a hole in a piston. When someone builds an engine its critical to get your tolerances perfect or stuff like this will rear its ugly head. Oil pressure really has nothing to do with excessive crank case pressure.

thanks chris ....i forgot to tell him also about open headers.....and what you said

No worries George, getting old is a b*tch, you probably have forgotten more than I know. :acme: