The Stovebolt Site Forums The Shop Area Engine Shop Vacuum thing-a-ma-bob on my old intake

What are those knarly little gizmo's that are sometimes attached to intake manifolds? It looks like an old grease cup, but it is inline with the vacuum line from the manifold.

Is it a check valve or filter of some sort?

Thanks,

Well Bill, those are the optional Knarly Little Gizmos. Sort of rare these days I think. Seldom seen so I'm sure many of us would appreciate a picture.

Dave,

Here are three pictures.

http://i40.photobucket.com/albums/e211/schickling/DSCN2905.jpg

http://i40.photobucket.com/albums/e211/schickling/DSCN2906.jpg

http://i40.photobucket.com/albums/e211/schickling/DSCN2907.jpg

Thanks,

A PCV valve?

I should have included something in the picture for scale. The top is only slightly bigger around than a quarter.

Does it rattle like a pcv valve?

Bill -
That is your "vacuum tank" for the windshield wipers. Those items are difficult to find as they tend to rust quickly or disappear for whatever reason. Consequently they are not seen or used that much. Instead a brass fitting is used in it's place and it will also work to propel the wipers. This little tank, however, actually stores up a small amount of vacuum to keep the wipers more steady during a driving in a rain event. I have often thought that a larger vacuum tank would work even better, but our engines apparently do not produce enough vacuum to store a large amount.
Joe

Joe,

Thanks. I guess it can't hurt to clean it up and stick it on the manifold. I don't plan to drive much in the rain and since the truck isn't finished, it won't be out in the rain for some time.

I think that would be better than just plugging the hole.
My Edelbrock has two vaccum holes on it, so I block that front one and use another on top behind the rear carb, but I might take it "up front" for looks. I had mine chromed some years back.
Joe

I think it's a check valve or "anti backfire valve". It's very similar in size and design to the ones used on vacuum brake boosters. The ones on a booster protect the diaphram and the one in the wiper line could stop the violent snap back the wipers do when the engine backfires. The vacuum chamber inside the motor is 4 or 5 times as large as this item so it wouldn't have enough reserve to even make a partial swing.