Originally Posted by Billabong
Originally Posted by PGT
some say that the face of the head is hardened and that you lose the hardness by excess skimming (this is the case with k series heads) but this can only be true if the material is exotic stuff like LM25 which is capable of hardenning but i dont know if YB heads are made of this. spoke to karl about this and he says skimming the head has no effect at all.
Cossie heads can go 'soft' if they've been subject to major overheating, you can get a hardness check done on the head to establish this.
not being funny billy here but could you explain this concept of 'going soft' in terms of the type of aluminium they are made of because as far as i'm aware the aluminium they are made of will not work harden or anneal. how exactly does it go soft?