PCV valve question

[tigernut]

I understand the purpose and function of having a pcv valve, but was wondering if I would be ok to run just standard breathers on each valve cover?

The only disadvantage I see is the loss of recirculation to aid in emissions.

Is this correct?

Doug

 

[tigernut]

I was told that running either a PCV valve or valve cover breather would essentially perform the same function, except the valve cover breather would be less emissions friendly.

The only drawback to a valve cover breather is apparently having to wipe oil residue off the valve covers.

I'm going to run a pcv breather from billet specialties. That should solve everything and it looks nice to boot (got corvette like flags on it):
http://www.billetspecialties.com/item.asp?cid=3&scid=4&pid=146

Doug

 

[JohnZ]

Just running breathers on the valve covers won't do much for crankcase ventilation, as there is no vacuum "pull" to keep fresh air flowing through it and out to be burned; about all they'll provide is pressure relief, which results in blowing hot oil mist all over the engine. Why not run the stock '66 PCV system?

 

[tigernut]

Yes, I had read that in the "old", pre pcv days, a hose hung down under the engine and the passing air created a vacuum. Interesting.

I'm not running a stock pcv valve setup because it won't look good on my engine, hence the pcv breather. (I've taken out the original engine and built a 383).

Doug

 

[tigernut]

John,

I meant to ask you why manifolds no longer come as they did on my original 66 aluminum one, where there is a tube for filling with oil as well as a connection for the pcv valve?

It sure helped to keep the valve covers looking "clean" without having holes in them.

Doug

 

[JohnZ]

Because the basic architecture of the Chevrolet PCV system changed in 1968-69; the intake vent hole in the back of the block disappeared, along with the oil/vapor separator can in the lifter valley, as did the front-mounted oil filler tube in the intake manifold; both the PCV intake from the air cleaner and the exhaust to the carb (through the PCV valve) were relocated to the passenger and driver side (respectively) valve covers. At that point, many of the aftermarket intakes followed suit and eliminated the hole for the oil filler tube.