View Full Version : venting of valve covers


Mr_Z27
03-26-2007, 02:11:39 AM
Should you run the pcv valve in one valve cover and an air breather in the other or should the other valve cover stay sealed. I do not have any other type of vent or breather such as the old style filler stack off the front of the intake.

jakeshoe
03-26-2007, 02:38:03 AM
For the PCV to be effective there must be a vent, so yes a vent in the opposite valve cover is the best solution.

Levi
03-26-2007, 06:05:38 AM
Yeah, engine has to breathe and exhale man. Atleast you dont have to use your EGR right?

Nate81camaro
03-26-2007, 12:03:39 PM
I should probably get around to putting a pcv valve in. Does it hurt the engine if I'm running a breather on both sides? Sorry for the NEWB question.

zekefreak
03-26-2007, 06:42:10 PM
By not running a pcv, blow-by gases will eventually contaminate the oil and then you could be asking for trouble.

My81Z28
03-26-2007, 07:21:23 PM
Does it hurt the engine if I'm running a breather on both sides?

I am interested to know the answer to this one. My valve covers have 2 holes each in them. I use 1 for PCV, 1 for oil cover, and the other 2 (1 on each side) for breathers. Why does pcv have to be hooked up to carb ???

Rick WI
03-26-2007, 07:24:28 PM
By not running a pcv, blow-by gases will eventually contaminate the oil and then you could be asking for trouble.

Not sure how you figure that?

Charlie Brengun
03-26-2007, 07:33:34 PM
i'd say that comes from here; http://en.wikipedia.org/wiki/PCV_valve

zekefreak
03-26-2007, 08:02:29 PM
I am interested to know the answer to this one. My valve covers have 2 holes each in them. I use 1 for PCV, 1 for oil cover, and the other 2 (1 on each side) for breathers. Why does pcv have to be hooked up to carb ???

The pcv is hooked to the carb for a vacuum source. This sucks out the air inside the engine drawing all the gases with it and reburns them in the combustion chamber. A breather on each side would be less efficient as it would draw air from the nearer breather and not the air inside the engine. You should block off the extra hole on the pcv side and use only the breather on the other side. The oil cover should seal tight and not allow air to enter. Also, VERY IMPORTANT!! Make sure the oil drain holes in the heads are open and not gunked up as this affects the pcv system, not to mention all the excess oil in the valve covers.

ps. Thanks Charlie!

tomsti
03-27-2007, 03:08:27 PM
I have two breathers and have run that way on other engines. May need to rethink this...

Question, at what point do big cams effect the functionality of a PVC system? If it operates on vacuum some cams will not pull very effectively. Assuming that the normal street engine operating range is going to be lower RPM.