What is this?

[malder]

Can anyone tell me what this is. Noticed that it isn't connected to anything, but when I have the engine running it sucks air.

Thanks

Matt

[lan240]

PVC valve

[malder]

Is it ok that it isn't hooked up? What does it do?

Thanks

[Dreco]

I'ts part of your smog equipment. I hose goes from the valve to your air cleaner. I just plugged mine. Of course I took off all of the smog equipment.

[Daniel]

It is a positive crankcase vent.It goes from that piece you showed to the big vent tube that comes out of your block,under the dist.Its job is to suck out the gas/vapor that build up in the block when the car is cold.My understanding is that not using it will cause gunk to build in your engine and reduce the lube properties of the oil( as gas mixed with oil is).It sucks that vapor out and reburns it.

[Victor Laury]

It's even of more value than you might think. Engines, our engines in paricular, run better when the crankcase has a negitive pressure, the more the merrier. The PCV system gives us enough. Some may contend that the "Dirty air" from the PCV and the valve-cover vent spoils the burn. But, I beleive it would only affect performance on a tired engine with lots of ring blow-by.

So hook it back up. The hose for this is very specific, as it has a larger diameter one end, where it connects to the engine vent tube (below the exhaust port of #1)

[JEFF]

Daniel and Victor Laury have it right!

The air that it is sucking in right now( not hooked up ) is a LARGE vaccuum leak - I bet your carbs are really rich to make up for it.

- Jeff

[Dreco]

Oh. that's right. sorry, it does go to the breather tube in the block. It's been so long since I've had that set up. I have the little air filters on mine. One for the block breather and one for the valve cover.

[JEFF]

Dave - if that set up is the way you like it - plug the PCV off.

- Jeff

[Dreco]

The first thing I did to my car( old engine) was throw all the smog equipment in the garbage, get a european balance tube and plug that HOLE.

[JEFF]

Dave - PLEASE--- Do not throw any Datsun parts in the garbage!

Offer them to the rest of us. Some things are hard to come

by.

- Jeff

[Dreco]

.... trust me, the parts I tossed....you didn't want. (seized smog pump, old hoses)