PCV valve rattle when running

discuspro · Jan 28, 2020

81 C10 305, long tube headers, no EGR, no TVS, 4 bbl Edelbrock 1406, aftermarket aircleaner, 8 deg base adv.

I've noticed ever since I put a new PCV valve on one of the valve covers it rattles like a machine gun when running. I have a new breather cap on the other valve cover. Is the PCV supposed to rattle like hell when the engine is running?? Seems like the little weight inside will wear itself away in no time at this rate.

Is this indicating a problem? The PCV could use a new grommet since it can come out pretty easily and is pretty loose. I've set idle to mid-600s rpm, and adjusted the edelbrock 1406 mix screws based on ideal vacuum (~18 in Hg). Using a vacuum gauge the engine vacuum at idle is pretty steady. I've noticed if I take the PCV valve out of the valve cover the engine runs rougher. Anything off here?

donnieray · Jan 28, 2020

My daily is a 350 set up much like yours and the pcv rattles like hell too. It's did it since the engine was new. I've changed the valve out to an AC Delco unit and no change. It dont bother me anymore. Three years now and its a very tight reliable engine.

Rusty Nail · Jan 28, 2020

Indicative of proper function while illustrative of that system's need for routine maintenance.

You are also well in tune , rest easy. :waytogo:

PCV is a metered amount of fuel your carburetor is tuned to burn.

SirRobyn0 · Jan 29, 2020

Normal, although some seem to rattle more than others, it's nothing to worry about.

MrMarty51 · Jan 29, 2020

With bad hearing, it makes all the rattled go away, squeaks too. :Caffeine:

SquareRoot · Jan 29, 2020

I won't even mention how awesome the ME Wagner dual-stage adjustable pcv is. I started somewhat of a movement on another site. Ended up with about 20 members springing for it. Great company to deal with. They gave us a group discount for 30 days.

discuspro · Jan 30, 2020

So the PCV grommet was petrified when I went to go remove it. I ended up grabbing a MPF 39210 PCV valve from Napa and a new grommet. After I put these two on the new PCV did not rattle and the PCV was held much more securely in the new grommet. As a result my previous idle flutter went away, and it idles and runs smoother than before. I need to run a new round of mix adjustments with what I suspect a slightly different vacuum pressure from making a better seal with a new PCV valve.

Memaloose · Feb 3, 2020

Bad hearing solves a lot of my problems. I had hearing aids a long time ago but heard too many rattles and squeaks, it didn't sound good.
Once I quit using the hearing aids, all my problems were solved!

SquareRoot · Feb 3, 2020

Memaloose said:
Bad hearing solves a lot of my problems. I had hearing aids a long time ago but heard too many rattles and squeaks, it didn't sound good.
Once I quit using the hearing aids, all my problems were solved!

Also the secret to a happy marriage.

Jerry phillion · Feb 3, 2020

PCV means positive crankcase ventilation. I was leaking oil past
My rear main seal, so I tried a pcv valve with no valve inside,
And my leak was almost all eliminated. It was too muck crankcase
Pressure caused by the regular pcv valve. I tried it on my 69 Z 28
And it worked the same. Only my experiences.

59840Surfer · Nov 29, 2021

discuspro said:
So the PCV grommet was petrified when I went to go remove it. I ended up grabbing a MPF 39210 PCV valve from Napa and a new grommet. After I put these two on the new PCV did not rattle and the PCV was held much more securely in the new grommet. As a result my previous idle flutter went away, and it idles and runs smoother than before. I need to run a new round of mix adjustments with what I suspect a slightly different vacuum pressure from making a better seal with a new PCV valve.

That noisy little "weight" inside the valve case is all metal and many times manufacturers will add a plastic coating to the floating valve itself in order to remove the rattling noise.

The plastic coated silent ones will wear away and need replacement sooner - while I have never seen the metal version do so.

59840Surfer · Nov 29, 2021

Jerry phillion said:
PCV means positive crankcase ventilation. I was leaking oil past
My rear main seal, so I tried a pcv valve with no valve inside,
And my leak was almost all eliminated. It was too muck crankcase
Pressure caused by the regular pcv valve. I tried it on my 69 Z 28
And it worked the same. Only my experiences.

The only way you can get pressure in the crankcase is if you've eliminated the KV-side of the PCV system. It is there to relieve any pressure in the crankcase and send those fumes down the throttle body or carb throat.

Did you add a custom air filter without the KV in it?

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75gmck25 · Nov 29, 2021

And just to help those who are extremely literal with pictures, the SBC PCV “plumbing” has the PCV valve in the driver’s side valve cover, and the sealed cap with air cleaner connection on the passenger side.

AuroraGirl · Nov 29, 2021

75gmck25 said:
And just to help those who are extremely literal with pictures, the SBC PCV “plumbing” has the PCV valve in the driver’s side valve cover, and the sealed cap with air cleaner connection on the passenger side.

Driver side forward abs passenger rear, locations that is?except in instances where the air cleaner is flipped probably but who knows. I guess an in-line 6 would be front to back. Front being the PCv and back being the connection.. maybe.

Rusty Nail · Nov 29, 2021

I remember that.

PCV valve rattle when running

discuspro

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