Technical To breathe or not to breathe, that is the question.

Currently I am running Z28 aluminum valve covers on my Chevy. To make my engine more period correct, I want to run the stock stamped steel covers without a pcv valve. I do have an oil fill tube that has a breather cap. My question is "would this be sufficient to allow the engine to breathe since I do not have a road draft tube on my later model block?" Or should I put a hole in the steel valve cover and use a pcv valve? Since I have no baffle inside the valve cover, I'm concerned about oil leakage. Answers are appreciated. Thanks

 

Should be fine with just one breather.

 

https://www.google.com/search?q=the...-nf-rev1&sourceid=chrome-mobile&ie=UTF-8#ip=1

 

@Moriarity

 

You need a breather in one cover to let air in. You need a PCV in the other to **** air out. Or a pcv in the intake and a breather in both covers. Or some combination of the above.

What you can't do is have a PCV and no breather, or a breather and no PCV. It'll work, but it aint ideal and you will need a big bag of kitty litter and cardboard.

 

If you have very little blowby & you don't mind moisture & acids in your engine IMO .

 

I know it won't be ideal but it will work.

 

Like Bandit Billy said, PCV in one valve cover, breather in the other.

On my race engines I ran a single breather into a "puke" can. However, these were not street driven engines. They were brought up to temperature and run hard. All the potential moisture was out of the crankase after a night of racing.

 

Might be interested in the Z28 valve covers if you want to sell thanks

 

Solid or any rocker cover engine needs a way to have air enter the engine and a way to have air (blow by) leave an engine. Up until the use of a PVC System the road draft tube was the exit and air rushing by it while driving “****ed” the air (blow by) out and usually the oil fill tube was the entrance.

Solid rocker covers on a SBC technically need the block with the oil separator in the lifter/pushrod valley and a fill tube at the front of the intake so even with a PVC system there are the 2 places.
When Chevrolet went to an opening in each rocker cover, one containing an oil sepatator , it was done because it was cheaper to manufacture. This also eliminated the intake manifold oil fill tube.

The final piece of the puzzle was the hose from the air cleaner inside the air filter to an addition hole in a rocker cover to make the system semi sealed now having clean air enter the engine to combine with blow by air thru the PVC valve and enter the combustion cycle of the engine at the bottom of the carburetor.

 

A proper PCV is the best way to go on a street car, race car not so much.

 

Find a way to make a PCV work.
And baffle it. I ran some dynamometer tests with and without a baffle to separate the oil mist from the PCV path and oil consumption increased dramatically without the baffle.
I also have one street rod with no PCV, only valve cover breathers and the oil becomes contaminated after a relatively short amount of miles.

 

Drill a hole in the manifold behind the carb, and install a Moroso "Baffled" PCV Grommet [# MO68772]

 

My street stuff has PCV on my race car it is just open to atmosphere if I would change anything on it, it would be to the exhaust or a vacuum pump.

 

Of importance is the carb, If you retro fit a PCV (not PVC) to an engine that had a road draft system you can't just plumb it in the manifold or carb base with a road draft carb or it will act like an air leak. The post road draft carbs are metered for the added air flow from the PCV system. JW

 

Thanks for all the info.I'll put a PDF valve on one valve cover. Ill try to find an old valve cover with a baffle that I can install. The oil fill tube with vented cap will act as air entrance. For those who asked I'm going to hold onto the z28 valve covers in case the steel ones don't work out.