the other thread reminded me of when I went to install a PCV valve in my new motor. when I went looking, there were 100s of them. seems each motor had it's on valve. there were differences in about all of them. I'm thinking it was because of the different displacement size engines... so with that being said, if you stroke a 302 to 347 then you will need a different PVC valve other than a stock 302... so would you look for one from a stock engine with the same displacement (347)...I thought bigger would be better so I got one for a big block only to find it sucked the oil out of the crank case... I had it hooked to the big port on the bottom of the carb. base, this may have been the reason for that... then I went to the other end...where to hook it to the vac. system... on older cars they are on the side of the breather base... this is where i am hooking mine as soon as I find a breather base PCV port. they use to come with aftermarket breathers. I have stuffed breather material under the valve but it sucked oil through anyway...just not as much. suggestions on this subject would be helpful...:Handshake
Pcv should go to base of carb, breath hose to base of aircleaner unless you ar running a open breather, a stock ls pvc will work fine in your application The larger the crankcase the weaker the pcv valve spring
X2. The PCV valve is passing oil on my 347. Its connected to the large port at the carb base. I don't know what applications the currently installed PCV valve is designed for. Didn't think about them being different for different sized engines. But, I thought the air cleaner connection went to the valve cover opposite the one with the pcv valve. Thought its purpose was to provide clean air to the crank case when blow by is less than the amount of air being sucked out by the pcv valve. I have an oil fill cap with an air filter installed on the opposite valve cover to allow clean air to be sucked in when its needed.
In the drivers valve cover, if you have a late model set of covers the pcv was made into the efi intake, ive got a spare older valve cover with pcv provisions here at the house
Thanks for that link. Think the following post may be describing the problem with my engine. by cjperformance » Sat Aug 14, 2010 5:38 am
I installed a breather in the front of the valley pan... I also installed the PCV valve in the back of the valley pan... with it hooked to the breather, it would eliminate the chance of a vac. leak if the PCV valve stuck open...
With them both in the valley i would have to question its scavenging abilities and posibility as a direct vaccum leak the pcv is supposed to be open at idle and light throttle were there is vacumm under the carb i would relocate it to the valve cove so it can pull the vapor from the oil return gallies jmho though
why would you think this? it's not hooked to carb. vac. anywhere... a friend of mine has a 6.0 in his '35 Dodge truck and has the old school breather/oil fill tube with the PCV valve installed like mine.
It should be connected to a vaccum source but your referance air and vaccum is pulled to close together you could always just add a second breather and nix thee pcv
