I'm forced to buy some new valve covers, because the guy who actually owns the finned aluminum vintage '68 Cal-Customs 'covers with on my 302 wants them back, because he's restoring a Shelby Cobra. They don't have baffles in them, and they're too short to clear my roller rockers, so I stacked and glued 3 gaskets under 'em to get the clearance I need. with this setup, I was still using about a quart every 300 miles through the PCV system. Yesterday, I capped off the PCV, cleaned out the wide open breather on the other side, and retuned the carb to match the mods. Had to go several stages leaner on both idle circuits, but now it's pulling 22.5" of vacuum at idle with the needle steady as a rock. After revving it up, it lets out a little puff of white smoke out of the open breather, but aside from that, it feels the same.

My question is, what are the advantages/disadvantages of keeping the PCV system? I have an Edelbrock 600 carb (#1406), and it is running terrific without the PCV, the idle is smoother and the motor feels more responsive. When I get my Edelbrock Elite valve covers in the mail, should I just keep dual breathers on them, or reconnect the PCV system? I've heard it leads to sludge formation in the oil, but my breathers are wide, wide open, so I don't understand how any pressure could build inside. Thanks for reading, and thank you for any advice, I'm stumped here! TK

 

Id say run the pcv system. It helps keep a negative pressure(ring seat better) in the crankcase that sucks out the old vapors and keeps the air in your motor nice and fresh.

Just my $.02

 

You won't really have a negative pressure. When people race, they seal the case and run it ito manifold vacuum. I had a vehicle where the PCV system got bloked. It dumped oil mist into the air filter and the oil sludged up from moisture. After fixing the rubber grommit that swelled shut (ot sludge), oil runs cleaner longer. Older vehicles used your proposed breather system. Perhaps this is why you HAD to change the oil every 3K.

 

Open breathers pollute, which is why California mandated PCV systems in 1961 and everyone had them by 1968. My '57 was an oily mess until I converted it to PCV. They also let in dirt and moisture. Even if filtered for dirt, moisture will condense in the engine as it cools.

Jim

 

Ok, one more dilemma:

I ordered the Edelbrock Elite covers that I've wanted, which have baffles, and are 2" taller than stock, so I'm okay there. I'm going to re-hook my PCV, because y'all have convinced me. but what about the other side? I have an open breather there now, and I mean open. No filter, just a slash guard to keep oil from slashing out. I was thinking about running a filtered breather, is this the best system? I think it makes sense, since the filter will take out dirt from the air that the PCV is sucking in through the other side. Every now and then I see crud in the oil, and I'm assuming that it must be coming from the oil breather. What do you think, run a filtered breather, run an open breather, or just cap it and let the PCV get it all? TK

 

TK, you must absolutely run a filter there. That is where the PCV system gets it's fresh air, and if it's not filtered, you are getting all sorts of dirt and grit into the crankcase.

I'm running a small K&N breather on mine. I would suggest a real filter such as this, rather than the foam-filled type breathers. The foam will get dirty and clog up, whereas the K&N's are cleanable.

 

I have an angle fitting that penetrates the bottom pan of my air cleaner housing, with a hose leading over to the PCV breather cap. Thus all the air entering into the PCV system is simply filtered thru the air filter cartridge. I figure I'm much more likely to look after the engine air cleaner cartridge than a separate small PCV breather, so hopefully more likely to have a functioning system that way!?! Steve

 

If you still have your smog pump running, use that for venting your crank case. I did that on my T-Bird and it worked great, Kept the oil out of the intake and dumped it into the exhaust instead.

 

Problem solved:

Edelbrock Elite valve covers got here friday, put them on, and no more oil consumption! the PCV is routed correctly, oil baffles installed, and the idle is as smooth as glass! I drove 360 miles from Charleston to Atlanta today going 75-80 MPH, with immeasurable oil use, and got 16 MPG! not bad for a 3 speed with a 4 bbl. I also used a Mr. Gasket filtered breather on the side opposite the PCV valve, and I must say, after a long trip with it, there's much less visible crud in the oil now that I have a filtered breather. TK

I'm a very, very happy camper!!!