Postby pete.collings » Fri Jul 05, 2019 11:12 am
I had a problem in the past with blowing from the head/barrel joint when mating a VHA head with a new make alloy barrel. I think the head had been lapped in too many times, as there was alloy to alloy contact between the head and barrel, rather than liner spigot to head contact.
I cured this by delaminating a composite copper head gasket used with Velocette singles, a piece of which neatly sat on top of the liner spigot.
Like Bob, I made sure there was a small gap between the alloy faces, although I cannot remember exactly what the gap was.