What is this part of my 240Z SU's?

[Murph]

My old carbs got nicked, so I got my hands on this pair. Just wondering what the fitting pointed to by the arrow below is for, as the old carbs (also 240Z items) did not have this?

I'm still a newbie when it comes to carbs, so need to know what I should do? Should they be connected to anything?

Thanks

[Daniel]

Overflow drain for your carb.

[Murph]

What should it run into?

[DakotaZ]

It runs into the back of your air cleaner housing. Since you don't have a stock air cleaner then if your floats mess up the fuel will just spill out on your exhaust manifold, doesn't sound like a good idea to me. I would think you could just run a line down below the exhaust manifold and it would be fine, but I'm no expert. I just had fuel spilling out of one once when I messed the float up.

[Murph]

Hmmm......I think I'll be doin something about that asap!

Thanks for the replies guys.

[Murph]

If my old carbs didn't have this overflow at all, would it mean it's non-essential and could just be plugged up?

[Victor Laury]

No, because it's more than an overflow, It's the bowl vent. Since the carb work on gravity feed the float bowl needs a vent. Otherwise you'd run lean when the flloat needles are operating nomally

[Chino 240Z]

No don't plug it. Your car won't run with it plugged. It is a air vent and gas overflow port for the fuel bowls. Plugging it will not let the fuel exit the bottom of the bowl and thru the fuel line into the nozzle on the bottom of your carb. I run mine to a common oil / gas fumes vent- plastic- canister, then a vaccum line breaths it back into the cross pipe of my intake manifold. I do this because my Z only sees a race track and their requirements are they don't want open oil or gas breathers / filters since they can cause oil drips onto the track. Stock air boxes would have a port to plug a vent hose upto to take the gas fumes to dispose of them into the carbs. Your filter is custom so this is why you have no nipple for a hose.

[Murph]

Thanks for the info guys.

I'm thinking I might just tap a fitting into the back of the new air cleaners for now.

[Zs-ondabrain]

Thats all fine and dandy but make sure there is not to much vaccum on the line or you'll suck the gas right out of your float bowl.

If you tap your filter make sure your filter stays clean or your carbs will try to get its air elsewhere :ie, your float bowl vent line

The canister mentioned by chino is a good idea and you might want to look at the engine photos else where on this site.

take a look at chino 240z's gallery for a clue about my babbling.

good luck, and hope this helps.

[Murph]

Cool cool......the pics show it clearly. I'll try and rig something like that up.

[Chino 240Z]

Okay here's the ugly part. It's just on old overflow container cramed into the corner with all the lines going to it and one coming from it to evacuate the fumes. I prefer the cool looking K&N filter vent idea, but on all my other cars they get messy and oily. This has been there for several years and has a few tablespoons of oil residue in the botton, I never empty it and is under the fender out of site, so its working good. As for the my dog Popcorn, she is always under my feet! Probably knows just about as much as I do about my cars.

Good Luck, Craig