crank case welding question

[pomps_pans]

A friend of mine is trying to weld a set of 1930s smaller displacement Indian crank cases. He is TIG welding then with 4043 filler, but he is experiencing cracking. He is pre heating the cases. I've used 4043 on Harley cast aluminum with success in the past, but I've never dabbled with Indian cases. Does anyone have any advice for him? Thanks

[tfburke3]

I have welded Indian cases using tig and 4043 and gotten great results.
The hardest thing for a welder to do is slow down.You need to weld a little,then take a break while the heat dissipates thru the case.
I mean really slow down,like 10 minute break between 10 seconds of welding.
Also joint prep,work a crack from hole at ends to center etc.
Tom

[pomps_pans]

I have welded Indian cases using tig and 4043 and gotten great results.
The hardest thing for a welder to do is slow down.You need to weld a little,then take a break while the heat dissipates thru the case.
I mean really slow down,like 10 minute break between 10 seconds of welding.
Also joint prep,work a crack from hole at ends to center etc.
Tom

Thanks for the tip! Are you keeping it in the oven around 300 degrees during the break, or leaving it in open air, or wrapping it in something?

[tfburke3]

around 250f preheat to start.A couple of cleaning passes,no puddle,with 100% argon and your already adding heat.Also a big plus is having a helium/argon blending station so you can add the desired amount of helium.Once you start welding the break time is on the bench letting the heat even out.Most of the repairs I have done on cases were easy locations like broken motor mounts .A hairline crack thru the pinion race bore into the cam case is to when I look for a replacement.
Tom

[pomps_pans]

Thanks for the advice! Sadly, I think this crack is headed for the pinion bore. He said he's drilled both ends of the crack and ground down quite a bit of parent metal, but after welding, a new crack forms. I'll pass along this information. Thanks again!

[41craig]

First of all, I am NOT a welder! That is why I am offering up a tip from my welder who has welded my cases and straighten my frames for years. I talked to him a long time ago about welding early aluminum cases. A lot of them extend the crack once you start welding. He said that the early, porous aluminum cases are impregnated with oil. He has found that the best way to get rid of the oil is to hot tank them. You MUST make sure that your automotive machine shop dips them in an aluminum only tank. The standard cast iron hot tank will dissolve your cases. This removes the oil and the welds will not extend. By the way, you can always tell my welds because the rod is still stuck to it.
Craig