Hitting ?

Could your PCV valve be hitting a rocker arm ? Looks like it's sitting a little deep to me. Can you feel it hitting?

 

Could your PCV valve be hitting a rocker arm ? Looks like it's sitting a little deep to me. Can you feel it hitting?

Possibly..Could also be the PCV valve responding to that lopey cam that you have installed.....Put a vacuum gauge on it and I bet it bounces all over the place.

 

PCV

I can't think of anything else.

Joe

 

PCV

I'm confused. You said when you take it out, the knocking stops.

Joe

 

Do you have a breather in the opposite valve cover or in the front of the intake manifold? I could not tell in the video. If not you need to install one to let fresh air into the crankcase so the engine can breathe.
Tom

 

Do you have a breather in the opposite valve cover or in the front of the intake manifold? I could not tell in the video. If not you need to install one to let fresh air into the crankcase so the engine can breathe. Tom

Agree, that may also be a possibility Tom...Sure sounds to me like the valve is shuttering back and forth.

 

PCV

Why do you need it, car is antique. Do you need it for Emissions?

Joe

 

Why do you need it, car is antique. Do you need it for Emissions? Joe

Using that intake manifold, with out the PCV valve, he has no crankcase ventilation at all, which has been necessary from day one...See link to Shop Manual, the paragraph on crankcase ventilation and the reason for it:http://chevy.oldcarmanualproject.com/shop/1955/55csm0617.html

 

Take it out and shake it. Is that the sound you're hearing?

 

I have had some cheap valves do that maybe weak spring, I got a good brand
like AC DELCO and it took care of it.
:gba:

 

Do you get the same noise if you take the PVC valve and just shake it. I have herd the noise before

 

the video "says"/shows the noise goes away when PCV is removed from the valve cover. Aftermarket valve covers, holes punched at the "factory" in the factory position so the chances of valvetrain hitting are nil. Big Cam? intake looks like a 325 horse 327 aluminum, vacuum provision in the manifold or from the base of the carb? Also when you remove the PCV from the valve cover the engine doesn't die? Because that would be a BIG vacuum leak. With all the shaking the engine is doing I'd touch different things and see if there is a loose bolt/part on it.
An engine running "fat" at idle, would clean up and run smoother with a vacuum leak and the engine would not shake as much and a loose part shaking might stop. just throwing thoughts out there.

Does the noise stop when you open the throttle up a bit?
one more thought, PCV's are rated to an engine buy the vacuum they are supposed to pull from the factory.
You might want to find a valve from a High perf. engine like a 302 Z28, or a 375hp 327 ect. They'd have a rating for a lower vacuum.

 

I'm wondering if an intake valve or more than one might be leaking back into the intake air stream giving a negative pulse causing the pcv valve to shut and open and cause the rattle.....maybe the valves are not sealing tight from misadjustment or worn valve guides or weak springs...

 

Does the noise stop when you open the throttle up a bit?
one more thought, PCV's are rated to an engine buy the vacuum they are supposed to pull from the factory.
You might want to find a valve from a High perf. engine like a 302 Z28, or a 375hp 327 ect. They'd have a rating for a lower vacuum.[/QUOTE]

Yes the noise stops when I open the throttle up a bit!

P.S. Thanks for the feedback everyone!

 

Does the noise stop when you open the throttle up a bit?
one more thought, PCV's are rated to an engine buy the vacuum they are supposed to pull from the factory.
You might want to find a valve from a High perf. engine like a 302 Z28, or a 375hp 327 ect. They'd have a rating for a lower vacuum.

Yes the noise stops when I open the throttle up a bit!

P.S. Thanks for the feedback everyone![/QUOTE]

You should be able to feel the PCV valve vibrating to make that noise.

 

There is a company that is highly involved with PCV valves for high performance engines. I know them personally and they have put in alot of research.
www.mewagner.com is their site.
Take a look at their site and perhaps drop Gene an email at gene.wagner@mewagner.com.
He just might be able to help you.

 

I have a 56 Chevy 210 Wagon with a 355 V8 installed. I was told I needed a PCV installed by a local mechanic. A few days later after the installation I am getting this tapping/knocking noise. It sounds like lifters contacting the valve cover but when I remove the PCV it stops. I went and bought another PCV and tried that but it is still doing it. I attached a video link below...Thoughts??

What u figure out? I have 56 chevy 3100 with 350 stock doing same its definitely chattering from valve in pcv going back and forth at idle does it worse when choke on.

 

Your replying to a thread from 2014