Crankshaft vent
 

i have a 67 chevy that had a two barrel carb. i took off the old carb and intake manifold. i replaced the intake with one i had #3927184 ( new intake manifold). the new intake doesnt have an oil fill tube so i replaced the valve covers with new edelbrock valve covers and put a breather in them. now i have no place to run my crank shaft vent hose to so i was wondering if i could just cap the hole since i have the breather in the valve cover???? any advice would help!!!!

Re: Crankshaft vent
 

Are you talking about a road draft tube or a pcv? You need a pcv to stop the engine from spewing oil and keep the gasses out of the crankcase. You should have a breather in one valve cover and a pcv valve in the other valve cover.

Re: Crankshaft vent
 

i have a breather in one and i dont have anything in the other yet what is this pvc? can you explain it more please?

Re: Crankshaft vent
 

pcv

Re: Crankshaft vent
 

Positive crankcase ventilation. It uses engine vacuum to suck the fumes moisture and other bad stuff out of the crank case. If pressure is allowed to build up inside the engine it can cause oil leaks by pushing out the gaskets. Way back in the day they used a road draft tube which basically just let oil blow out of the engine onto the ground which served as the vent but that isnt the best way for obvious reasons.

Re: Crankshaft vent
 

so do i connect the old crankshaft vent (that went to the air filter before) to the pcv valve in the other valve cover? i would post a pic but i dont know how. sorry

Re: Crankshaft vent
 

Ahhh i understand now. Forget about the tube that went to the intake. Its not needed with the aftermarket breathers that go into the valve cover. The other valve cover should have a hole about the same size as the one you put the breather in. INstall a pcv valve into that hole with a grommit. Then run a vaccum hose from the pcv to the large vacuum port at the base of the carburetor.

Re: Crankshaft vent
 

ok cool but what about the old hole? it is still open so can i just make a cover for it and plug it or do i need to do something else with it?

Re: Crankshaft vent
 

The hole in the air cleaner?

Re: Crankshaft vent
 

Pictures would be great...

Gary

Re: Crankshaft vent
 

no the hole going into the block next to the distributor. i would post a pic but i dont know how to post it. i have one on my comp right now, everytime i try it asks me for a http: for my pic or something

Re: Crankshaft vent
 

Ohhhh your engine has a road draft tube. If you run a pcv and breather you can eliminate the road draft tube by plugging the hole.

Re: Crankshaft vent
 

is there a recommended way of plugging it or can i just make a metal plate and throw a gasket on it to plug it? i really appreciate the help.

Re: Crankshaft vent
 

As long as you seal it up you shouldnt have any problems. As I said you need to make sure you have a good working pcv system in place or you will start have bad oil leak issues.

Re: Crankshaft vent
 

thank you alot, you have really helped me.

Re: Crankshaft vent
 

here is a good visual on the PCV system. Your truck never had one, and it is in fact a smog item, however, it is one of the pollution control pieces that HELPS keep your engine lasting longer.

Re: Crankshaft vent
 

You can plug the breather hole in the rear of the block with the correct size of freeze plug. I believe the correct size is 1-1/4", but you might want to double check that as it's been a long time since I've done this.

Re: Crankshaft vent
 

Thats a great picture andy I was trying to find something like that but had no luck. A picture is worth 1000 words.