Wood wrote:Hi Kia.
Thanks for the reply. Forgive my ignorance on this. Your comment on this engine been a 2nd generation caught my attention and a bit of a relief.Is there a reference which states what serial numbers fall into 1st, 2nd generations.
My serial number on this is 22A 1130. Which, I hope it is not a1st generation. I’ve been told that you can no longer get heads for 1st gen engines. So if it’s a second gene then that takes a load off. At least until I get the bill on what I need to do.
Thanks again.
Mark
Onex107 wrote:You are correct with your assumptions about the valve seats. But technically speaking, here we go, plasticity is not a metallurgical term. Yield strength comes close to it. That's the strength at which it yields and does not spring back. Aluminum expands four times as much as steel valve seat when it's heated. micro inches/degree C. per inch. That's probably why they put a max on head temp. When an alum head expands the holes get larger not smaller. Valve seats have to be shrink fit when they are installed, by several methods, and pressed into the seat in order to be able to absorb the heat expansion without coming loose. The head goes through an expansion/contraction cycle with every engine run which might also tend to loosen head bolts. It would be a good idea to torque check them once in a while. I need change for my two cents worth.
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