Can C-2 Valve Covers be Adapted for Breather?

[Richard W.]

I am wondering if it is possible to effecively adapt C-2 valve covers for a breather. Specifically, I put a new GM crate in my '63 using the 327/340 intake and exhaust manifolds. The old set-up has a tube from the oil filler tube to a PCV valve in back of the carb. Right now I put some aftermarket valve covers with a breather on each side. I would really like to use the original finned covers to make the engine look closer to factory. Not trying to pass this thing off as a "corrrect" engine, just want the car to look a bit more genuine.

Using the PCV system on my '75 as a guide (and not 100% as how these things should work--not an engineer, just a bean counter who loves cars), would it be possible to take an oil dripper from a donor valve cover, drill a hole in one end of the cover, run a hose from that hole to the connection coming from the bottom of the air cleaner and have a workable system?

Assuming the theory sound, since the oil filler tube is at the front (near the air cleaner connection), should the hole be at the rear (farther from the oil filler tube? Would I use a PCV valve from the air cleaner to the valve cover and another from the oil filler tube to the carb? If not, which location should have the PCV valve? Finally, I assume that only one valve cover would have to be drilled, true?

I appreciate that the whole discussion flies in the face of a factory restoration but also know a lot of us have driver Vettes and face ourselves in this situation. As always, thanks for your response.

[Jim T.]

Re: Can C-2 Valve Covers be Adapted for Breather?

If you are going to use the original intake and carb set up as before the engine change that is all you need to continue using the finned valve covers.

[Richard W.]

That would be my first choice but...

my mechanic said I had to use breathers or would eventually blow a seal. Yes, I am using the original 324/340 intake manifold with a '64 Carter AFB carb. Right now the connection at the bottom of the aircleaner attaches nothing.
My mechanic said that the original setup had an internal breather system and showed be a hole at the back of the block that was orginally used.

Have you used the orginal covers on such a setup without any problems? If so this would be great news. I am looking forward to hearing more.

[Joe L.]

Re: That would be my first choice but...

Richard, Jim, and Richard-----

You must have some sort of crankcase ventillation. Using an original intake with a later block without the rear breather provisions does not provide any crankcase ventillation, at all.

It may be possible to add a breather to the rear of the block, but it would involve some machining. Also, it's possible to add breathers to the 7 fin valve covers, but I don't like the way the look with breathers added.

One thing that you can do is to use a breather type cap on your manifold-mounted oil filler tube. That will provide some crankcase ventillation, but maybe not enough. You see, in these old installations, the crankcase breather tube provided the "motive force" for crankcase ventilaation by the drafting effect. With a breather cap, alone, or even with the addition of valve cover breathers too, there is no "motive force" to provide proper ventillation.

Another thing that you could do is to use the 69+ style aluminum covers in conjunction with the appropriate matched air cleaner. This will provide a PCV system like that used on 68+ engines. The valve covers won't look "stock" for a C2, but they do look good.

[John H.]

Re: That would be my first choice but...

I saw a combo just like yours a month or so ago, and the owner had installed a fitting (for the hose from the air cleaner base) in the inboard wall at the rear of the driver's side finned valve cover, as the "intake" point for the PCV system (replacing the original "intake" point that was at the rear of the 327 block). He had the original oil filler tube with the fitting, PCV valve, and hose to the rear of the carb. This makes a fully-functional crankcase ventilation system. The "intake" point should be near the rear of the engine to expose as much of the crankcase as possible to the incoming flow of fresh air as it flows forward and out through the filler tube PCV fitting.

[Richard W.]

Great news and a couple of final questions

John,

Thanks for your response. Sounds like I am on the right track. A couple of minor questions. Did he have the hose coming out of the top or the back (like I am thinking of doing so it will be quite as noticeable). Finally, what are your thoughts on needing an oil dripper. I assumed I would need one with all that oil splasing around.

Thanks again for your response.

Dick

[John H.]

Re: Great news and a couple of final questions

Dick -

The added fitting was on the inboard wall that faces the intake manifold, about 2" forward of the rear of the cover. The owner wasn't with the car, so I couldn't ask if he fabbed a baffle inside the cover at the fitting opening or not (I would). The normal airflow there is from outside the cover to inside (if the PCV valve is working) rather than inside-to-outside, but I'd still like to see a simple baffle there.

[Jim T.]

Re: That would be my first choice but...

Richard and Joe, I got to thinking after I made my previous post about your old block having a tube in the rear. Glad that this was corrected.

[Edward McComas]

Re: That would be my first choice but...

A friend of mine with a 66 recently tackled this problem. He was using a crate motor with original 66 intake and aluminum Corvette script valve covers. His original plan was to modify the block like an original 66 block, but he found out that this would negate the warranty on the engine. He ended up modifying the passenger side valve cover. He had a hole drilled in the inboard side (closest to the intake) of the valve cover, about two inches from the rear. The then had a tube welded into the hole. This tube connects to a hose, which connects to the breather on the botton of the air cleaner. I do not know if he used any sort of baffle in the tube in the valve cover.

Not totally original, but it isn't real noticable (like it would be if the hole was in the top of the valve cover) unless you look carefully. Since this is a driver, it works fine for him.

P.S. This car represented the 1966 model year in the historic motorama from Flint to Bowling Green last year.

[Richard W.]

Re: That would be my first choice but...

Thanks. Would it be possible for me to contact your friend so that I can get more details? My e-mail address is rwathen@attbi.com.