K&N Valve Cover Breather

[c3po]

I have a small block chevy on my 1983 El Camino that has 366,000 miles on it. I remember about a year ago I needed to replace my valve cover breather, a neighbor gave me a K&N breather that was brand new that he no longer needed, it was still in the box.

On the other valve cover I had a new PCV, my thought was that this K&N breather would allow more fresh air in as well as letting some pressure escape easier since it was more free flowing.

It did not work out to well, I had oil that was leaking out the rear main seal, maybe there was to much pressure, so I went and got a chrome breather with the foam inside and everything was fine, no leaks.

I had thought about a breather on both valve covers, of course I would not have a PCV, and I figured I would have oily residue inside the engine and on my windshield.

Someone told me that it was better to have the PCV Valve on there because it acts like a suction and pulls the harmul fumes out of the crankcase, whereas a breather just vents it out which is not that good.

Moroso makes a Crankcase Evacuation System that has 2 breathers and runs a hose on each 1 down to your exhaust pipe, I have read that this is for drag racing and even though I have a free flowing dual exhaust I have read that if it is not free flowing enough this Moroso unit will not work, something with the check valve not opening up.

Any thoughts on why that K&N Breather did not work would be apprecaited.

 

[rg200amp]

Originally Posted By: c3po

Someone told me that it was better to have the PCV Valve on there because it acts like a suction and pulls the harmul fumes out of the crankcase, whereas a breather just vents it out which is not that good.

That is my understanding aswell.
PCV=healthy engine

 

[TallPaul]

Right, breather instead of PVC valve would be bad news. Old days there was a road draft tube that essentially drew fumes out of crankcase by low pressure of air whizzing past tube opening under car (you can see where this would not work on grandma's short-trip church and pharmacy driven car--hence, hardy driven sludgers in the 1960s). EPA did not like road draft tubes, so we got PVC valves and closed system instead.

 

[Chris142]

I have one of those K&N breathers on my pickup. It must be cleaned pretty often or it gets plugged up.

 

[mechtech2]

Maybe the K+N was undersized.
There shouldn't have been a difference.
And a normal PCV system is a wonderful thing to have. Keep yours in good shape.
The exhaust pipe thing is special needs race car stuff.

 

[c3po]

Originally Posted By: mechtech2
Maybe the K+N was undersized.
There shouldn't have been a difference.
And a normal PCV system is a wonderful thing to have. Keep yours in good shape.
The exhaust pipe thing is special needs race car stuff.


When I had the K&N breather on it was a small 1 and it may have been hitting the valve cover baffle, I have a different grommet on there now, so maybe when the weather gets warmer I will check everything out.

 

[Dualie]

On all my late model diesel pickups the first thing i do is install a road draft tube. the last thing i want is all that oily air clogging and coating the inside of the intercooler.

Also all of my big diesels CAT, IH, Cummins have had them as original equipment

 

[NYEngineer]

That Moroso system only works on open exhaust at WOT.. Not a part for a street car.

 

[c3po]

Originally Posted By: NYEngineer
That Moroso system only works on open exhaust at WOT.. Not a part for a street car.


You are 100% correct, my El Camino only sees WOT once or twice a year.