how do I cap off smog pump inlet on stock air cleaner housing??

[super74]

I've searched....but haven't gotten the information I need. I was wondering if there is any way to properly cap off unused smog pump inlet barb (back of the air cleaner housing/'70-'72 SU stock intake) if one were running the carburetors...but not the smog pump. There aren't any vacuum or "heater hose bypass" caps that are large enough to cover the hole, that I know of. The only other option I see is to size the barb and hope that K&N makes a crankcase vent filter with the correct sized opening, and just run it like a second tiny air cleaner. Otherwise, I may be forced to run aftermarket filter housings. Certainly not the end of the world, but I'd like to avoid this if possible.

 

Sorry if this has been covered somewhere before (it might have been), but so far I've had no luck finding an answer. Any information would be greatly appreciated. Thanks.

[Tony D]

I think I used a 5/8" heater hose cap from the 'Help' section...it may have been bigger. As I recall the NAPA where I got them has truck parts, so it may have been larger. But I'm almost positive a 5/8" (15mm) fits.

[super74]

I've got to check the size on that barb, but you may very well be right. Finding the "larger" sizes can be a hit-and-miss proposition at some of the parts stores, as often the staff doesn't keep close tabs on low inventory, but I'll definitely check it out. Thanks for your response.

[essdeezee]

Another place I've found caps for vacuum type stuff is a local place called industrial liquidators. They have a wide array of sizes for fairly cheap.

 

Yet another place I've found things like this is Home Depot! They call them screw protectors, and they can be found in the specialty nuts/bolts drawers. IIRC, they go up to 1/2". If this is the case, and you need something larger, head over to the section where they sell end caps for things like chairs and barstools.

[super74]

Those are great ideas. I think the mistake I made when I had originally asked the question was mixing up the inlet and the outlet on the smog pump. It appears as though, at a glance, that the outlet (to the exhaust manifold and anti-backfire valve) is larger than the inlet.

 

The end caps for bar stool legs really is a great idea, though. I should've considered that when I was originally brainstorming. Thanks for your response.