On 30 Mar 1997, James Charles Ruwaldt wrote:
> In a slightly different direction, Tom and Ray Magliozzi, our talk show
> mechanics, have said that older cars need lead to cushion valve seats.
> Therefore, there are lead substitutes for that purpose. However, that's
> the only place I've heard that, and I tend to agree with Egil, that lead
> shouldn't be that significant.
Funny you should mention those guys, I have never heard of them before
two days ago when I friend of mine borrowed me some tapes. I even got to
hear a listener asking exactly *that* valve question. Strange coincidence.
Click'n Clack seems to give sound advice some of the time, but definitely
not always. And they refer to LBCs as junk. They're sometimes funny, though.
Anyway, if was not valve seat recession I was discussing, but rather a
belief that lead was significant for the Lucas PI system. Which I think
is mostly superstition and witchcraft.
Exhaust valves are quite another matter altogether. Cars with valve seats
machined in a cast iron head can develop trouble with the exhaust valve
seat recession. The problem is much more pronounced with hard driving/
high temperatures, if you just cruise around town you won't notice.
Egil
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