aluminum epoxy for cast crankcase

[jrick]

I was fortunate enough to be one of the ones that purchased this specific 22 hp engine that has a documented problem of a bolt backing out of the counterbalance and cracking the crank case.
Now to save a 1700 dallor investment i want to seal that crack with an epoxy, because several places tha weld stated it would be pot luck as they do not know the contents of the aluminum.
Looking for a recomendation for this application. It would be placed on the outside, crankcase produces vacuume not pressure so sucking air in the crack would be concern not visa-versa. This is small, hair line cracks. Oh as I just said, about vacuum, I wander while oil came out? all advise welcom.

 

[swall]

Get rid of the "pot luck" risk aspect and have a chemical analysis performed on the casting. There is portable XRF equipment that can handle this task. Once you know the alloy, perform a proper weld repair.

 

[ornerynorsk]

A 4043 Tig rod is going to handle 90% of your automotive cast aluminum. Getting it clean enough to take a good weld is another story . . . most shops also do not like to weld on engine blocks so I suspect that is why you're not having luck with them.

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[1gibson]

Devcon and Belzona have nice, suitable products if you go with epoxy.