Crankcase breather

[zedron]

Friend needed a new way to vent his crankcase pressure because his Gatorade bottle wasn't working anymore so I told him to buy me some fittings and filters and I will make you an aluminium one for free. I need the practice so why not. I had the 1/8 sheet already at no cost along with the pipe for the filters. Here it is.

Then I decided to make one for my car as I needed one anyways. Before paint below.

After paint with Rustoleum Hammered Black and Installed.

[zoama]

Why so many fittings and filters ?

[agent4573]

The welds look really good, but I'm kind of confused as to why so many filter elements as well....

[zedron]

There are 6 lines that vent the motor. Two go to the back of the block, two go to front of valve cover, and two to rear of valve cover. When you have a breather you want the venting to be as free as possible because if the motor is pushing more air out though the lines faster than it can escape the breather out the say 1 filter instead of 2 or three, then it will actually start to create a vacuum and pull oil out of the motor into the breather.

The breathers help with excess blow by gas typically found in boosted application or extreme naturally aspirated applications. Typically these gases get routed back into the intake but why would be want to be putting dirty air into our race car? The factory design as well as aftermarket like I have also help remove excess moisture that can build up in the crankcase via blow by as well. The ideal way would be to also create a baffle in the breather that has a line running to the exhaust. This will create a mini vacuum in the breather to help pull gases out the lines into the breather and then out through the filters or get sucked into the line that goes to exhaust to be burned up.

[Jason]

I have a catch can on my car that I built also. The only downside I see to doing this and venting it freely means that you can then smell the gases. It happens that mine vents on the passenger side which is right in front of my cabin air. Every once in awhile I can smell it a little. Eventually I may end up routing it to my exhaust but for now I am at least keeping my port and polished intake track free of that oily gas.

[zedron]

I have a catch can on my car that I built also. The only downside I see to doing this and venting it freely means that you can then smell the gases. It happens that mine vents on the passenger side which is right in front of my cabin air. Every once in awhile I can smell it a little. Eventually I may end up routing it to my exhaust but for now I am at least keeping my port and polished intake track free of that oily gas.

That is a downside but if you remove the filter elements entirely and have exhaust gasses pull the crankcase gasses out then you will have no issues at all. I was thinking about doing it that way but the benefit I would get would be suffice to do the work to get it routed because I would have to redo the exhaust in order to get enough pressure to pull the gasses out.