mc_renn

I was replacing my air filter the other day and noticed a small crack - aprox. an inch on the bottom of the air box.

The car starts and runs fine. Can I put some expoxy over this or do I need to a new air box?

mc_renn

oh car is 1983 911 SC

Peter Zimmermann

Tough call! Is it possible to take a picture of the crack and post it?

While you're looking check the seam where the upper and lower sections of the box are glued together (especially on the left side, below the intake air snout of the filter cover). There will be a row of Phillips-head screws along the seam. That seam should not have any fractures/cracks along it.

Now, please look at the right side of the box. There is a flat, vertical surface a couple of inches below the fuel distributor. Is there a blue sticker there, or remnants of a sticker?

Edgy01

If you can really source all the possible air leaks you can try JB Weld--the 911 owner's friend.

mc_renn

Thanks guys. I'll try to look at it closer tonight and post some pics.

Thanks Edgy01 - i just bought some JB Weld on the way home!

rusnak

I fixed my girlfriend's Maza airbox with JB Weld and some foil tape that is used on AC ducting. The SC airbox is basically the foundation of the entire system, so it needs to be rigid. I agree - it depends on where the crack is located.

mc_renn

Hi Peter:

I checked the seams and they look great -- no cracks or fractures that I can see.

There is no blue sticker or remnants of the sticker.

Here is the picture of the crack. It is in the upper left hand corner on the bottom.

theiceman

that pic is too close i can't get a frame of reference
the last thing you need to do is suck a chunk of JB weld in to one of your intake runners. i would feel much better using marine silicon. I think that would be pliable enought o make a seal and be flexible. less likely to suck a hunk in and if you did it would burn up,

Just a thought , no real expertise

mc_renn

Thanks Iceman - I was thinking the same thing. I'll take another pic and post it. But I'm leaning towards your idea. Any particular type of Marine Silicon I should buy?

Edgy01

Ideally, use a product known in the aerospace business as RTV -- room temperature vulcanizing -- sort of like GE silicon, only the best aerospace grade stuff around.

theiceman

pretty well all silicons are RTV i believe these days .. On my airbox I used a product called 3m marine adhesive 5200 to glue my airbox back together. It works pretty well but i have to tell you it took nearly 3 friggin weeks to caur .. must have been a special RTV that assumed your room was on the friggen sun. if you can get a quick drying formula that would be great . in fact i think i saw it on the shelf and didn't get it . it is available in any marine supply store.

Peter Zimmermann

1&2 above indicate that the airbox has been replaced, that's probably good.

Can't get a reference on the pic - pull back a bit to get more of the unit into the pic.