Losing my mind trying to weld the gm cast aluminum coolant pipe. How hard can it be to weld a hole without creating more holes? LOL

Called Griff as usual when I get stuck and he recommended brazing it. Wasn't expecting that. Apparently GM cast parts are notorious for being a pain in the *** to weld on. So did some digging and found the video below. Got some of the benzomatic AL brazing rods and a MAP gas canister from Home Depot. They worked perfectly. Holy smokes brazing cast aluminum is so much easier than trying to tig weld it!

 

Alumiweld, Muggy Weld (has a bunch of different names) works, but it's not.. good. Despite the youtube videos, in my experience, it should require as much prep as an A/C Tig weld, benefits from a large surface area. But the bond itself is not the greatest on cast. If you must braze, use a product with flux. On my A/C hard lines I used https://www.harrisproductsgroup.com/...num/ALCoR.aspx - has a built in flux (like rosin core solder) and flows way better than the nickel stuff - but it's primarily designed for tight-fitting pipe joints on thin wall aluminum - not void filling, it's very thin and runny (but for a tight fitting joint it's amazing). For larger pieces (junction blocks) I used Al-Braze 1070 which is 1070 aluminum and flux, which is a better bond, but the temperature to melt 1070 is dangerously close to melting thin-wall aluminum tube, so you'd have to be real careful about making sure where your torch was pointed.

But the trick I found for tigging cast aluminum is to basically just have the grinder ready. Run a heavier cleaning action (and gotta resharpen that tungsten), float the impurities, flapdisc them off, then continue. TFS just did a video on working with crap castings - the suggestion of "small beads to float and then tie them in together" is also another valid strat.

 

Agreed. I basically did the bulk of the initial structure weld mating the two pipes with tig. Like you said, lots of grinding. Then going back with aluminum brazing rods to fill the small holes left over and so far so good.

 

Thanks for the tip of cleaning passes then flap disc. I recently welded braces onto my diff and did a couple of passes just to get the cleaning action to run then went back and added filler/heat. That made it easier, I have always struggled with aluminum welding.

 

Some updates...

The brazing of the aluminum coolant pipe didn't work for ****. It leaked no matter what I tried. So I ended up using the oem pipe with an add on cross pipe and oem rubber coolant connectors. Not as clean looking, but no more leaks so it's a win.

The 1" clutch master cylinder was a bit ridiculous. I had about 0.5" of pedal travel for clutch engagement/disengagement to work with essentially making the car nearly impossible to get going from a stop without spinning the tires. Back down to a 7/8" clutch master. I think my previous issues with the 7/8" clutch master was from improper bleeding on my part. I had my wife do single clutch presses and would bleed on each press of the pedal. Spoke with Andrew at Keisler and he said to do 10 pumps and hold on the 10th and bleed. That worked way better and the clutch is now certainly fully bled.

Had an exhaust leak at the marmon flange on the passenger side. It looks like the exhaust was settling a bit from the heat and left a small gap. Widened up the mounting holes about 1/8" on the rear to give a little play and that should allow them to seal up nice and snug.

My AIM gps signal disappeared so I dug into the tunnel wiring and found the ittle connector for the gps cable had come loose. Wrapped it with some high strength fiberglass tape and put a small relief cut into the cable sheath to prevent the cable from being pulled. Seems to be fixed.

 

Great build, great thread!

I'm working on an LFX swap using the Keisler kit in an RX-8. I'm veering off the beaten bath by using an MV7 transmission as well. I actually ordered a new one from a dealer, but it hasn't arrived yet.

I'm trying to figure out the differences in mounting. Do you have any pics of your mounting solution? Or even just of the transmission itself? I'm trying to figure out how it differs from the MV5 which just has two vertical bolts going into the bottom. Looking at your custom trans mount, you also use two bolts through the bottom?

Also, what's the word on the VSS sensor on the MV7? Is it just on the passenger side? Same connector, etc?

Thanks!

 

Did you ever get your Rush?