Fixing a Ruptured Bore in my Weber Carb.

I would go in a different direction...
Since it is a 308 carb(yes), I would buy one for 3-400 bucks and rebuild it...???

If it were a Sand cast, 40 DCN1 where there are no spares AND NO parts either, and the car won't run with out it, then extraordinary efforts are required...

I would bore/hone the body out, and sleeve it to the closest original bore size I could, finish hone it to size, re-shaft and re-butterfly plate it and replace ALL of the lead plugs, you will have to chase the progression holes for burrs...and perhaps make caps inorder to obatain proper access..small compromise in the bigger picture I think??
To "do it right", as we all like to quip...requires that you do all 4, and then double check performance gas flow capacities with a flow bench-with out this steep, the ENTIRE exercise, is a waste of your time, and otherwise considerable efforts, and obvious skills....

 

The Nov Dec 2009 copy of The Home Shop Machinist magazine has a brief write up on Oxy Acetylene soldering aluminum. Kent White is the author, he is well known for his metal working. He does not mention preheating the metal before soldering it. He recommends cleaning the hell out of it with 70% isopropyl alcohol and a stainless steel toothbrush. For soldering 0.050 inch aluminum he recommends a number 1 tip with the inner cone two metal thicknesses and a feather of two inner cones. He also cautions against overheating it, the solders and flux are heat sensitive.

Good luck, and keep us posted.
Cheers Jim

 

I just talked to the technical support gentleman at Eastwood regarding the anti-heat compound. He assured me that this compound is rated to absorb/dissipate up to 3000F. Additionally, he said that this compound is perfectly suited to my carburetor application. It's ordered and on the way.

Ciao,
George

 

So George,

I read in one of the threads what sounds like you're going to fix this hole with the idle circuit screw in place and hope to avoid machining this afterwards because the repair material won't stick to the idle screw tip???

I know I must be nuts thinking this is what you meant??? Of course I'm nuts regardless ...

Bob S.

 

That's a big 10-4 good buddy!

Ciao,
George

 

OK. So here is a picture.

Ciao,
George
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I see the white rectangle, what's the big blurry thing?

 

The big blurry thing is the 4mm hole by George. I'll have better pictures later.

Ciao,
George

 

I sure hope that "shakin' hands" photographer isn't the one doing the delicate welding ... ;>)

 

Hopefully this is a little clearer.

Ciao,
George
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Still working on it. Somehow the surface is not being prepped corectly by me.

For the time being here is a shot I took with a magnifying glass. Ah, yes the magic of optics.

As a side note, I tried to replicate that kind of a rupture on my practice carb. No matter how hard I tried to turn the idle screw past the stop point, I could not. Now, I can't help but wonder if the carburetor was somehow compromised from a previous fire?

Ciao,
George
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Thanks for the update, I was wondering if you had any luck with it.

cheers Jim

 

A couple people have mentioned heat sinks. Aluminum is a heat sink and anything you do to remove heat from one part of the carb will also take it away from the area your trying to heat up. Especially true when using a gas torch vs something like a tig torch.

My first inclination would be to find a way to machine out the area and press some sort of plug in place. It doesn't look like it's going to be easy from the pics

 

George,

I ran across this today and thought something in there might help out.
The info on welding magnesium was interesting.

http://www.welding-technology-machines.info/index.htm

Bob S.

 

The link didn't really seem to go into any detail? The more thought I give it I still think drilling out the threads and all, reaming to size and pressing an aluminum plug into place and then drilling and taping the plug as the factory did in the original cast piece is the way to go. Probably heat the carb up before attempting to press in the plug in an oven.