Valve seat to plug cracks

[Tree Hugger]

Have searched the forum but must be too thick to find the relevant posts. I am trying to decide how essential these repairs are, perhaps on a scale of 1 to 10 .
Thanks
David

 

[The Sock]

Unless the cracks run all the way through, they aren't a major problem.
I believe they were the reason behind the cast iron skull heads.

 

[Tree Hugger]

Is there a risk the valve seats become loose?

 

[pf1]

I don't like the look of that first pic but I will await our expert's verdicts because I would like to know myself.

 

[sfcpiet]

Is there a risk the valve seats become loose?

Eventually, yes. But they won't fall out, the alloy edges are swaged over the seats.

Those heads make a nice conversation piece as a doorstop.

piet

 

[Tree Hugger]

…… or a brolly stand

It’ll be going back on the lovely engine Keith rebuilt back in May. Just need some work done on the head I suspect.