[markwemple]

Bought pop-off valve for the '78 (cis airbox). It didn't come with epoxy and in the instructions it simply says ...epoxy... So what epoxy should I use?

[Mark]

Most car-parts stores stock epoxy in a two-tube affair that has to be mixed before using. I didn't use enough of the stuff when I installed my pop-off valve, and a healthy backfire dislodged the damn thing (better than a blown airbox, I guess). I reinstalled it, using gobs of the stuff and, so far, it's holding.

[William Miller]

While on the subject...
Have you guys with Pop valves ever changed the O-ring?
It took a fellow Dorki to come up with the size when I was looking.
Mark, can you post it here for future reference?
It should be on the instruction sheet.
I ordered them from McMaster Carr on line.

[Rick V]

I have a trick that I used on my (and other cars) to keep the valve in place no matter how hard the backfire. I take a Dremil tool and remove the "ribs" from the bottom of the airbox where it interfeers with the valve placement. The valve will now sit flush with the bottom of the box. Once that is accomplished, I remove some of the length of the valve so it doesn't protrude too far into the airway. When it gets glued down it has a good surface to seal against, plus it looks a whole lot better.
I also just use some of that 2 part clear epoxy, like the 5min type.

[VaSteve]

Mark, just some all purpose epoxy.
Bill, http://www.dorkiphus.net/porsche/sho...ht=valve+steve

[Lupin..the..3rd]

Originally Posted by William Miller

I ordered them from McMaster Carr on line.

McMaster Carr is the best! If it exists, they have it, and in 5 different colors, 7 materials, and 14 sizes. I just wish they had a huge retail store, right next door to me.

[markwemple]

Thanks, guys!

[wludavid]

Just make sure the epoxy you get will bond to the material you're working with. I just got back from the Home Despot and opened up the epoxy I bought to use on ABS plastic. Turns out there are big letters on the package, Will not bond polyethylene or polypropylen products. Ooops. Guess it's back to HD.

[markwemple]

I guess the point is try to buy a plastic specific epoxy and try to create as much surface are as possible.

[Vicegrip]

Originally Posted by wludavid

Just make sure the epoxy you get will bond to the material you're working with. I just got back from the Home Despot and opened up the epoxy I bought to use on ABS plastic. Turns out there are big letters on the package, Will not bond polyethylene or polypropylen products. Ooops. Guess it's back to HD.

Little if anything non heat based bonds to those two. I would venture a guess that the air box is not made of milk jug and there is a non solvent based 2 part glue that sticks well. JB Weld comes to mind. Unless you are using a slovent based glue you should clean and rough the surfaces up to as corse a surface as reasonable.