pcv valve

[kidatforty]

OK. What's the story. The pcv is a one way valve that connects the intake manifold with the crankcase. Should it be drawing air at idle? I always thought that they should only draw after hard manifold vacuum drops so that it does not affect idle. I have a vented cap so that when the pcv is connected, it sucks air through the cap into the crankcase through the pcv and into the intake manifold. I don't like additional air entering that does not go through the carb. It affects my idle so I have it blocked off right now. I thought of maybe running the hose to the air cleaner so that it does draft emissions into the engine but that is not what service manuals say. What do you think?

[mdill]

The PCV valve should go to manifold vacumm ! You want fresh air to be pulled
though the crankcase to suck up the gases (and crap)that get past the rings. The valve
is a controled leak that should not really effect idle the the extent that the carbs
idle circuit can not compansate for. Put PCV valve back where it belongs, richen
up the idel screws a tad reset idle RPM and you should be fine.

Mike D.

[Jeepzilla]

Look inside your vented cap and you should see a metal filter medium that looks like a scouring pad. It gets oily so you should clean it in solvent from time to time. The reason it goes to manifold vac is that it does draw at idle. Ported vac won't.

Newer models (my '81) do draw thru the air cleaner, but the ducting is different: mine goes from air cleaner (with a little filter)-->back of valve cover-->into crankcase-->out of crankcase in front of valve cover-->PCV valve-->manifold vac. You would have to try to find the best match of engine/modern ducting and then try to copy that. Really, your setup works OK.