JB weld 600deg. F for pop-off valve?

[Larrybrook]

I have just purchased a pew pop-off valve (from our host) for my '74 CIS air box. After reading a few posts on this topic, I am unsure whether to use JB Weld epoxy (rated up to 600 degrees F), or is there a superior product? Or, does the preparation make all the difference? I have determined a 2" hole saw may be a tad too small and it might be necessary to file the pop-off valve in order to seat it properly. ALSO, it is abundantly clear the "ribs" need to be filed down, to make a good seal. AND roughing up the pop-off valve and cleaning everything with alcohol will only help adhesion. BUT I have read epoxy may not be the best product since some pop-off valves have "popped-off" from their installation. NOTE: She runs like a jeweled watch, AND I have never had a back fire BUT I'd rather avoid one altogether. FINALLY...I do own a 2 1/8" hole saw, should I use it, or stick with the 2" and tweak the fit?

Thanks in advance.

[rusnak]

JB Weld should work ok, just make sure it doesn't drip onto the motor as it cures. Your airbox should never ever get anywhere near 600F.

[Larrybrook]

So...2" diamter hole saw, or 2 1/8"? (I have both)

[E Sully]

Drill a 2" hole. It is an interference fit and will seal, don't file down the ribs unless it does not sit well after a dry run, it sits on top of them.
http://www.pelicanparts.com/catalog/images/misc/PopOffValve.pdf

[Bob Kontak]

There is some stuff called Marine-Tex that is pretty knarly (meaning tough). For this application though, you don't need any "extra" strength. Even JB Kwik would be just dandy.

[Larrybrook]

It just seems like you would achieve a better adhesion for the epoxy with more surface area on the pop-off valve. Anyone else want to chime in?

[Larrybrook]

I used the 2 1/8 " hole saw first, and cut only to the bottom of the ribs, then went with the 2" hole saw to complete the job.


THEN I used the Dremel, to remove the unwanted ribs and rough up the contact area for the pop off valve and JB Weld marriage.


After a couple of test fits and some more filing etc. here's how she seats.



And finally the end product, epoxied into place.




In my opinion this is a better way to hold it in place, rather than relying on the taper of the pop off valve with minimal JB Weld holding it all together...ESPECIALLY when vacuum leaks cab be such a nuisance.

My two cents.


Cheers,

[Bear911]

Hi Larry

I did mine pretty much the same way as you did. My only concern was that it could weaken the air box by cutting through the extra rib. But then the valve itself becomes somewhat integral and possibly adds strength again. I don't think it will create any issues.

I'm sure there will be much less chance of a leak this way. My CIS was removed when I did it, so I didn't have to worry about pieces of plastic ending up in the runners.