snomobeelr Posted April 30, 2017 Share Posted April 30, 2017 I noticed there was oil leakage almost like oil spray on the hose from the back of the carb to what I think/thought was a PVC Valve breather that is on my car on the driver side. The passenger side is just a breather where I also fill the oil. So I pulled out the driver side and did something I never did prior. Looked inside.. See the picture Breather 1 . I am assuming it is not supposed to be blocked like that or am I wrong. And even if not do I have an issue since there is actually oil in there ? Or is that what it is for just not supposed to be blocked? Quote Link to comment Share on other sites More sharing options...
GatorDog72 Posted April 30, 2017 Share Posted April 30, 2017 That breather likely doesn't have a check valve in it like a factory PCV valve, it just breaths. Using the breather as a PCV system will just cause a huge vacuum leak at idle. Run a breather in one valve cover and a PCV check valve on the hose that goes to the back of the carb. My carb didn't have a port for PCV, I just use two breathers in the valve covers. The oil gets dirty very quickly without the PCV though. Here's whats the valve should look like. It just goes in the same spot in the valve cover where the breather goes. Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted April 30, 2017 Author Share Posted April 30, 2017 Holy crap this could be my long standing issue with my engine and vacuum issues. So my valve covers also have Baffles in them. Guess I'll find out if that PVC valve will work or if I have to remove a baffle? Thank You Quote Link to comment Share on other sites More sharing options...
Leghome Posted April 30, 2017 Share Posted April 30, 2017 I had a breather like that on my 350 SB in my 72 and went with a PVC valve similar to what Gaterdog posted and have had no problems since. I had the same look you did on the bottom of my hose oil drippage. Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted May 1, 2017 Author Share Posted May 1, 2017 Ok I ordered the PCV valve - ACDELCO-CV774C. Just wondering if it is gonna work with the baffle in the Valve cover. Quote Link to comment Share on other sites More sharing options...
Leghome Posted May 1, 2017 Share Posted May 1, 2017 Mine aftermarket worked with the baffle Quote Link to comment Share on other sites More sharing options...
overdrive Posted May 1, 2017 Share Posted May 1, 2017 It should be fine. Factory valve covers had baffles. The baffles are designed to restrict the oil from getting into the carburetor, but allow air to flow. The Positive Crankcase Ventilation, (PCV) valve is simply a check valve. It only allows flow one direction. If you have a used one, just shake it to see if it rattles. If it does, then it's not gummed up and stuck, and it's good, as long as it's not cracked somewhere. Dan Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted May 1, 2017 Author Share Posted May 1, 2017 Thanks everyone. I just meant the baffle seems close to the top and wondering if the PCV valve will sit on it or if the baffle will block the bottom of PCV valve. Quote Link to comment Share on other sites More sharing options...
snomobeelr Posted May 1, 2017 Author Share Posted May 1, 2017 Just want to verify.. I always thought the PCV valve is installed on the Driver side valve cover with the Hose going from PCV Valve to the base of the carburetor. Passenger side is just a breather and oil fill. Do I have this correct? Thanks Quote Link to comment Share on other sites More sharing options...
GatorDog72 Posted May 1, 2017 Share Posted May 1, 2017 It can go in either side if you want Quote Link to comment Share on other sites More sharing options...
GatorDog72 Posted May 1, 2017 Share Posted May 1, 2017 The Positive Crankcase Ventilation, (PCV) valve is simply a check valve. It only allows flow one direction. Yes, but its more than just a check valve. The PCV valve is designed so that under high manifold vacuum (idle), it will flow very little. When the throttle is opened and manifold vacuum goes down, it opens completely to allow crankcase vapors to get sucked into the manifold. Here's a link to good article explaining fully how the system works. http://www.baldwinfilter.com/literature/english/10%20TSB's/94-2R1.pdf EDIT: The link isn't working but that's the correct address for it. Quote Link to comment Share on other sites More sharing options...
1970mcss Posted August 18, 2017 Share Posted August 18, 2017 If the wrong PCV valve is used, can it cause the car to idle improperly? The car came with the wrong valve in it (CV682C). I ordered a CV736C which should be the correct valve. When my car comes off of high idle after I start it, the car seems to want to die at stops. If I drop it into neutral it runs fine. Any ideas???? Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted August 18, 2017 Share Posted August 18, 2017 readjust the idle mixture screws and then adjust idle speed, while you're at it...double check the timing Quote Link to comment Share on other sites More sharing options...
1970mcss Posted August 23, 2017 Share Posted August 23, 2017 Sam, I reset the mixture screws and reset the idle, runs great. The prior owner must of done the 1 1/2 turns. I will still be checking the timing, thanks 1 Quote Link to comment Share on other sites More sharing options...
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