C3 PCV system

How is the PCV system in a 1971 suppose to be setup.
My hoses run from a canster on the drivers side to the pcv valve and then to the bottom of the carb.
On the passenger side a hose goes to the air cleaner from the valve cover.
Someone told me that pcv valve is not suppose to have vacuum from the bottom of carb he says it holds the pcv valve closed.

The PCV valve gets hooked up to manifold vacuum either at the base of the carb. or at the intake manifold.

B2B posted this link elsewhere, I hope it helps.
http://en.wikipedia.org/wiki/PCV_valve

I think the '71 PCV valve is a single hose that goes to the bottom of the carb.

Your passenger side is correct.

So everyones pcv valve is running to bottom of the carb.
This guy does not know what he is talking about.

The vacuum sucks the blowby into the cumbustion chamber. The reason it is at the base of the carb is so the the blowby gets "evenly" distributed to all cylinders with the fuel mixture.

SmokinBBC said:

The vacuum sucks the blowby into the cumbustion chamber. The reason it is at the base of the carb is so the the blowby gets "evenly" distributed to all cylinders with the fuel mixture.

Click to expand...

A Holley



A qjet



Almost always the 3/8" port on a carb is the pcv port. Just flip any carb over to check.

Does your alls Pcv hose come off the canster on the drivers side.
My pcv valve has a T fitting on top of it.

Mine is a '70 454 which does not have the fuel vapor canister.

I think the base model '70 and then all models '71+ have the eec system(evaporative emission control). This system uses a vapor canister to capture fuel vapor from the carb and tank in the canister. When the engine is cranked, the vapors are sucked up through the PCV line into the carb....hence the tee in your line to the vapor canister.

The system uses a non vented gas cap. I think on the 71 you have a filter at the bottom of the canister which gets replaced every 12k miles or so.

Well you learn something new every day.
So,you say there is a filter in there I bet it is the one that came with the car.

zz71s said:

Well you learn something new every day.
So,you say there is a filter in there I bet it is the one that came with the car.

Click to expand...

Here is the canister. You can see the filter at the bottom.

http://www.zip-products.com/Zip/pro...alse&mscssid=03D4F327E4E2344E4A4B725384F10DB6


Here is the filter:

http://www.zip-products.com/Zip/pro...alse&mscssid=03D4F327E4E2344E4A4B725384F10DB6

SmokinBBC said:

The vacuum sucks the blowby into the cumbustion chamber. The reason it is at the base of the carb is so the the blowby gets "evenly" distributed to all cylinders with the fuel mixture.

Click to expand...

Yep - and the reason the passenger side intake is under the air cleaner is so that the air that is drawn through the crankcase is filtered.