CIS Airbox Plastic?

[patkeefe]

Hi all,
I am repairing some seam leaks in a CIS plastic airbox. From what my research indicates, this plastic is a form of PPS:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&sqi=2&ved=0ahUKEwjcweyzgNvQAhUEZCYKHY55BbIQFggiMAI&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FPolyph enylene_sulfide&usg=AFQjCNGCh4syW3eCSswunxLnCtzP_BAvig&sig2=_vyyOGDcbs2SQUjGzS021A&bvm=bv.140496471,bs.2,d.cGw

Evidently, this requires a very special form of adhesive, two of which are Loctite products. Has anyone used these specialized Loctite adhesives, and what kind of results did you have?

My airbox need to be sealed not only for vacuum, but also pressure-turbo application.
TIA
Pat

[tirwin]

There was a thread a while back where someone investigated what kind of stuff to use. I'm trying to remember anything that would be useful in a search. I don't recall how it ended up.

You doing an EFI install?

[tirwin]

I think this was the thread:

Air Box Repair Myth or Reality ??

[john walker's workshop]

I'd fab a metal one for turbo app.

[timmy2]

Pop off valve going to pop on boost?

[fanaudical]

I agree that the airbox is most likely PPS (discussed in this thread):

What to use to repair CIS airbox?

Last time I sealed my CIS airbox I used the Loctite "plastic welder" two-part epoxy. Some discussion of that here:

Sorry - Yet another CIS troubleshooting thread...

The epoxy seal has held up well after a few years; no leaks yet. However, I don't have a turbo application and would be wary of an epoxy-repaired/sealed airbox holding up to pressure (when the epoxy is applied from the outside).

One thought I had was to mask the openings and pour in something like a gas-tank sealant and swirl around the inside to coat all surfaces/seams. I never did pursue this, but it seems that would be a more robust sealing job (especially for something like a turbo application). I'm not sure how to deal with the spray bar for the cold start valve...

[patkeefe]

Originally Posted by tirwin

You doing an EFI install?

Yes, I am tired of the CIS. I went with an SDI from Racetech. I am machining parts for the install, and trying to get the airbox I cut up to quit leaking. I may have to break down and buy some of that $50 epoxy.

The other epoxy I tried just essentially laid on the surface. Except for a few pinholes, it didn't leak under 20 PSI in water. But, I could easily lever that layer of epoxy off with an X-Acto knife, so I have my doubts about it's durability. It appears that stuff would work for vacuum only applications...which is likely why there are so many recommendations for epoxies that "work".

I had a Webb airbox, but I sent it off to a fellow Pelican for his use. I can't see cutting up a valuable airbox for this conversion. Those things are rare. If push comes to shove, I will build a new plenum for this application.

[patkeefe]

Dennis, when I was running the original airbox with the modded BAE kit, I calibrated the pop-off valve in a tub of water. Basically, it was a plumbers test plug. I blew air into the box at 15 PSI to make sure the plug did NOT blow out, then I would give a quick burst of compressed air at 100 PSI to make sure it did. It is hard to simulate a shock wave with compressed air, but I never had any problems with it.

fan, I read your posts prior to this. I see you have also done a bit of looking into this matter. Thanks for your research!

[patkeefe]

BTW, I don't have the cold start spider in either of my airboxes (a big port and a small port). I did modify the small port box to accept the early SC runners (my car is early SC) by machining some rings from CPVC and gluing them on. IIRC, late box has 1.325" ID openings, and early is 1.500". It is a big difference.

I once sealed a fuel tank with that yellow sealer stuff by pouring it into the inside. It may be fairly tricky to duplicate that effort with an airbox, and I wonder how long that yellow stuff will stay put in swirling pressurized air.

[hoss4659]

There are a lot of parts made of various plastics on our Pcars. Are there some tests to establish what kind of plastic a part is made from? Such as shaving off a small amount to see if it softens or dissolves in acetone, or MEK, or alcohol, or ?? Would be helpful to know when dealing with a NLA part that has broken and you need to attempt a repair.

[patkeefe]

I am very reasonably sure it is made from polyphenylene sulfide. I spent an hour or so this morning on the phone with Henkel, MasterBond and one of Henkel's technicians. PPS is quite difficult to bond as in the patching and seam sealing required. They did give me some part numbers of products to apply which should work. I am going to buy a tube of one of them, a single part epoxy which needs to be oven cured, and see how that works out.

[tirwin]

With EFI conversions gaining popularity, I would like to see someone make a plenum/throttle body that would be a drop-in replacement so people didn't have to cut up air boxes.

Good luck on the turbo application! I'all be interested to see your progress.

[timmy2]

Originally Posted by tirwin

With EFI conversions gaining popularity, I would like to see someone make a plenum/throttle body that would be a drop-in replacement so people didn't have to cut up air boxes.

Good luck on the turbo application! I'all be interested to see your progress.

Interesting read here :
78-83 Aluminum air Box

[patkeefe]

Dennis that is a really nice aluminum airbox. Generally the first one of anything costs a million dollars, and the price goes down from there.

tirwin, I will see how the repair goes, before I decide to make my own for the EFI application. I'd have to make it from steel, 'cause I can't weld aluminum.

[timmy2]

Lol, visions of Dr. Evil "one million dollars" pinky finger to lip...

I probably shouldn't have shown that post to Tim knowing how much he likes shiney things...

[tirwin]

Dammit, Dennis! You're making my tinkeritis flair up again!

[Avanti]

I feel pretty fortunate to have one of these metal air boxes on my 77 complete with pop-off valve. Someone more familiar can comment on who made it and how long ago. Its very accurate and high quality from what I can tell.

[patkeefe]

Avanti, that looks like a Webb airbox. They no longer make them.

[ClickClickBoom]

Originally Posted by patkeefe

Avanti, that looks like a Webb airbox. They no longer make them.

Not like the Webb I had on my car, there were a few mfgs in that era.

[Nux]

Originally Posted by patkeefe

Yes, I am tired of the CIS. I went with an SDI from Racetech. I am machining parts for the install, and trying to get the airbox I cut up to quit leaking. I may have to break down and buy some of that $50 epoxy.

The other epoxy I tried just essentially laid on the surface. Except for a few pinholes, it didn't leak under 20 PSI in water. But, I could easily lever that layer of epoxy off with an X-Acto knife, so I have my doubts about it's durability. It appears that stuff would work for vacuum only applications...which is likely why there are so many recommendations for epoxies that "work".

I had a Webb airbox, but I sent it off to a fellow Pelican for his use. I can't see cutting up a valuable airbox for this conversion. Those things are rare. If push comes to shove, I will build a new plenum for this application.

Don't use epoxy - it will not hold due to the vibrations. Initial test will be fine, but only for a short drive. Also I'm not sure the bond it self will hold gasoline exposure.