Crack underneath valve seat

[Christoph Thuerey]

Hi Guy,

today I removed the valve seats from my Uno turbo cyl head. By that I've seen that one crack between the valve seats is slightly deeper than expected.
When new seats are mounted they'll slightly interfere with each other, so there will be no partition wall and the cracks between the other seats are gone.
But what shall I do with the one on the photo?
I can TIG weld aluminium alloys and have AlSi 12 filler rods. I think head is from Silumin gamma, which is AlSi10Mg. I've tried it today with an old head and it worked pretty well even without pre-heating. But is it necessary? Will the crack deepen?

Thanks Christoph

[Guy Croft]

Junk the head.

GC