PCV confusion

[pfay82]

Hi everyone,

I have a question about my PCV system. The back hole in the valve cover has a little elbow with a filter attached. That's all back there. The front has the PCV valve, but there's no hose on it. I have a Motorcraft carb. Where would the hose hook up to if I had one?
Thanks.

[AMC of Houston]

Originally, there was a hose that went from there to the air cleaner housing, and the little filter was inside the housing.

Most aftermarket air cleaners have an adapter and punch-out hole for that hose.

The PCV hose went to the bottom of the carb.

[mudkicker715]

Refresh my memory please. Wasn't there a amc bulletin to take a valve type thing on the pcv hose out of play. I assume this happened to pfay2, but you never know, since it wasn't mentioned. Just a thought.

[AMC of Houston]

Yeah.  That recall bulletin removed the electric shut-off valve (which closed off the PCV air flow at idle) from the PCV line, and replaced it with a new PCV hose that had an orifice inside it (basically reducing the PCV flow at all times over what it would be with a full-diameter hose).   I still have a couple of those recall kits in my parts stash.

[86Woodgrain]

Yeah.  That recall bulletin removed the electric shut-off valve (which closed off the PCV air flow at idle) from the PCV line, and replaced it with a new PCV hose that had an orifice inside it (basically reducing the PCV flow at all times over what it would be with a full-diameter hose).   I still have a couple of those recall kits in my parts stash.

Do you have a copy of that bulletin? My car has the PCV shutoff solenoid valve but I unhooked the electrical connector because it was causing too much flow back through the air filter on the line coming from the back of the valve cover.

I'm not sure I want to do the recall kit, I'm thinking I probably should...

[Canoe]

This is the easy way. Pull PCV air out of the valve cover through elbow #47057 (attached). Always open, and as required, the airflow is always limited by the small hole size. Hole's size & surrounding shape also limits oil splash up the hole, so better than a larger hole with an airflow limiting restriction somewhere down the line. (Some people modify their old PCV valve to use here; always open and small hole for limited airflow. Most reports are that the limiting elbow works better.)

So you can remove the PCV valve so there's no valve to fail closed. You want filtered air going into the valve cover:

• There's small air filter cans made to fit rubber gromets where the valve was. Independent of the air cleaner, but another thing to buy and crank case air can leak to atmosphere when the engine is off.
• Or run an air line to the air cleaner on the filtered side to get filtered air. Crank case air stays within the air cleaner (with its closed breather vent that limits carb fumes getting to atmosphere) when the engine is off.