[AT] [External] Re: Valve Seat Inserts

[Steve W.]

Gunnells, Brad R wrote:
> Wasn't there something also with the change from leaded to unleaded
> fuels? For some reason I thought manufacturers started putting harder
> valve seats in later model engines due to the limiting of lead. I
> could be way off here but I thought I'd heard about that back in my
> dirt track racing days.
> 
> Brad

Yes, the engines built during the days of leaded fuels need to have the 
seats replaced because the plain iron seats won't hold up for long 
without the lead. I've seen small blocks eat the exhaust seats in a few 
thousand miles. As they started to build them for the unleaded fuels 
they generally used induction hardening on the seats or inserts on the 
real performance engines. It can also be an issue on small air cooled 
engines that used cast iron valve seats built in those years as well.

-- 
Steve W.