help with an intake manifold

[motorcyclemac]

Hi folks,

I ran into a little problem with a project and need some help.

I took on a job to install a t-6 aluminum bung in the face of a Chevy BB intake manifold in the water passage just to the passenger side of the water pump bypass hose fitting.

I used a Syncrowave 180SD on AC, maxed out, 3/32 pure tung nicely balled, 3/32 4043 rod wave was set biased to penetration. I prepped it well removing all the casting flash on the aluminum intake and filed the surface of the bung fitting. Cleaned it with acetone and preheated it with propane to about ~300 degrees F. I had a hard time getting it hotter as the manifold was sucking heat fast.

I welded it and it looked ok...not great. Kind of dull grey..not shiney.

Bottom line...it weeps. I have to fix it again..and I am wondering if my machine has enough power to work with this mass of aluminum. 180 amps is barely enough for 3/16 and the wall of the manifold is a good 1/4 inch ....not to mention the rest of the manifold is a BIG heat sink.

should I have back gassed it when I did it to help with porosity... or is is porus from lack of heat and a cold weld?

What do ya'll say?

Thanks
Mac.

[nocheepgas]

Back gassing probably wouldn't have helped, think you need more heat. If the manifold is new, as in not contaminated with fuel and oil, and if your wife is
a) away for the day
b) left you for another guy
c) out with the girls
d) lets you do all the cooking

you might try to repair it after placing it in the oven @ 500 deg for 30 minutes. Otherwise you need 250 amps +

[motorcyclemac]

I was afraid that was the case. I shot it with the Fluke temp gun after preheating it and was amazed at the thermal conductivity of that manifold. It is used...and has had anti-freeze in it...

Sounds like I better clean up the weld...and have him take it to a fellow with more amps...

I don't think the wife will tolerate it going in the oven.

Thanks
Mac.

[urch55]

What about placing it in a gas outdoor grill.??
Bob