Pelican Parts Forums

Pelican Parts Forums (http://forums.pelicanparts.com/)
-   Porsche 911 Technical Forum (http://forums.pelicanparts.com/porsche-911-technical-forum/)
-   -   Cracked airbox it seems JB Weld maybe (http://forums.pelicanparts.com/porsche-911-technical-forum/1036786-cracked-airbox-seems-jb-weld-maybe.html)

piscator 08-09-2019 05:47 AM

Flojo,

I wouldn't either and don't. I just thought I'd try and be thorough.

G450X 08-09-2019 05:53 AM

Quote:

Originally Posted by Bob Kontak (Post 10552665)
Found a 38mm for $275 just now.

I guess I need a better search engine...

Flojo 08-09-2019 06:02 AM

Quote:

Originally Posted by piscator (Post 10552724)
Since we're on the subject, I might as well ask. Would there be a market for air-boxes made in carbon fiber?

I fear the price as a show stopper.

mike sampsel 08-09-2019 08:41 AM

Quote:

Originally Posted by boyt911sc (Post 10552674)
Installed this brand new CIS air box for a PP member several weeks ago and cost less than $250.


Tony


$250 installed, I'll take two! :)
Are these 44 mm ports for $250?

boyt911sc 08-09-2019 09:44 AM

Clarification.......
 
Quote:

Originally Posted by mike sampsel (Post 10552925)
$250 installed, I'll take two! :)
Are these 44 mm ports for $250?



Mike,

$250 was the price of the new CIS airbox to replace the cracked one. I can not post the name of the source in this forum. The engine was a ‘83 SC US spec with the -2R intake runners (34-mm ID). The new airbox is now identified using the OD measurement for spec.

Tony

Edit:
Looking at the invoice, it was $273 not $250. My mistake.

piscator 08-10-2019 05:19 AM

Thanks Flojo, you're probably right about the cost. There goes my dream of buying a 959 with the profits from my carbon fiber air-box venture! ;-)

mike sampsel 08-10-2019 11:57 AM

Quote:

Originally Posted by piscator (Post 10553567)
Thanks Flojo, you're probably right about the cost. There goes my dream of buying a 959 with the profits from my carbon fiber air-box venture! ;-)

Now I’d pay big bucks for a titanium air box ... just saying ... but it would need to be a package deal with a titanium exhaust system :cool:

mike sampsel 08-10-2019 12:02 PM

Okay, so with two passes of JB weld my airbox passed my smoke test with no leaks. Hope this does it so my rpm goes down with the oil cap removed. As I said the car ran well before this anyway. But I’ve got the CIS on the operating table so on went mr JB.

Airbox for my runner size is about $480.

Reiver 08-10-2019 01:08 PM

Quote:

Originally Posted by mike sampsel (Post 10553996)
Okay, so with two passes of JB weld my airbox passed my smoke test with no leaks. Hope this does it so my rpm goes down with the oil cap removed. As I said the car ran well before this anyway. But I’ve got the CIS on the operating table so on went mr JB.

Airbox for my runner size is about $480.

Do you have the large port box?

mike sampsel 08-10-2019 01:59 PM

Quote:

Originally Posted by Reiver (Post 10554048)
Do you have the large port box?

I think so, they measured 44 mm. 78 and 79 are special :)

Reiver 08-10-2019 03:57 PM

Quote:

Originally Posted by mike sampsel (Post 10554086)
I think so, they measured 44 mm. 78 and 79 are special :)

So are all of the Euro's from that period thru 83…

bpu699 08-10-2019 05:12 PM

There’s some videos on YouTube fixing plastic with screen mesh and a small iron. Just burn the mesh into the plastic. Harbor freight sells the heating iron. Permanent fix...

fanaudical 08-10-2019 07:59 PM

This is all covered in a couple of other threads.

The best epoxy I've found for the plastic used in the CIS airbox is 'Loctitte Plastic Welder'. It actually does bond to the surface (not just stick).

The plastic used din the CIS airbox is not a thermoplastic (it's a thermoset) and it doesn't respond well to attempts to repair with thermal welding.

piscator 08-11-2019 06:55 AM

Fan,

Your comment on thermoplastic and thermoset plastic answers some things I've encountered and wondered about. If my understanding is correct, thermoplastic is the stuff they make kayaks out of -- is it called 'roto-moulding?'

If so, in my experience nothing sticks to that stuff! I've used heat to repair small cracks in a friends kayak. So far it's never opened up, but I always worry about it. It may be just psychological, but I have trouble trusting a repair that I haven't added material to.

piscator 08-11-2019 06:57 AM

Hi Mike,

I'm working on your titanium air-box and exhaust, but I'm afraid we'll have to add a few zeros to the estimate price! :-)

930cabman 08-11-2019 07:08 AM

My vote would go to a new airbox. For $250. what is your time worth fooling around with repairs?

Sure, anything can be fixed but for how long will the repair last?

fanaudical 08-11-2019 07:35 AM

Quote:

Originally Posted by piscator (Post 10554515)
Fan,

Your comment on thermoplastic and thermoset plastic answers some things I've encountered and wondered about. If my understanding is correct, thermoplastic is the stuff they make kayaks out of -- is it called 'roto-moulding?'

If so, in my experience nothing sticks to that stuff! I've used heat to repair small cracks in a friends kayak. So far it's never opened up, but I always worry about it. It may be just psychological, but I have trouble trusting a repair that I haven't added material to.

Rotomolding is a manufacturing process. You drop a hot glob of plastic into a warm mold and then spin the mold to coat the surfaces and make the shape. Most kayaks of this type are made from polyethylene, which can be welded for repairs.

Polyethylene doesn't allow bonding to most adhesives. There are some that will bond but difficult to find.

patkeefe 08-11-2019 07:56 AM

The world of plastics is much broader than one paragraph on pelican parts 911 technical forum.

Paulporsche 08-13-2019 06:55 AM

piscator,

Basically, thermoplastic plastics are one that set up as they cool, after being formed with heat. Heat will soften them. Think car model plastic. Thrmoset plastics give off heat as they cure. Unless subjected to exteme heat, they will not melt with heat. Think a cooking pot handle.

Patkeefe is correct. there's more to it than this, but that's the basic difference.

UROParts 08-13-2019 08:06 AM

JB Weld handles heat well up to 500 degrees F, and there's a high-heat version that goes considerably higher. For low-temp applications, West Systems G/Flex is less brittle than most epoxies and is a fantastic 24 hour epoxy.


All times are GMT -8. The time now is 07:36 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2025, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2025 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website


DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.