Greetings . . .

There was a posting earlier that received lots of replies and included some rather interesting side discussions and tangents. I kinda like that sort of posting - makes for interesting reading and lively discussion . . . though I digress . . .

Some felt all the banter was off topic and that separate postings were in order.

So I am offering the board both . . . a separate posting that cuts right to original question:

PRESSED IN HARDENED VALVE SEATS FOR YOUR VINTAGE ENGINE - Yes or No?

I am building a 216 based on specs from Bill Fisher and Roger Huntington. I have a NOS cylinder head from war time production. Should I hand it over to some machine shop for them to machine and press in hardened exhaust seats?

Some will say that hardened seats are "the best insurance I can buy." But how do I go about choosing the right seat?

If my machinist or I choose wrong there can be problems:
Morris Club Owners
If one chooses the wrong material or they aren't installed correctly then one can end up with heat transfer problems that will lead to failure alot sooner then errosion from unleaded gas:
Valve Seat Installation
How do I know what materials are compatible with a World War II era head? Does anyone know?

When GM originally cast the head "back in the day" they certainly didn't intend for it to be machined in this way. They expected it be used with leaded gas.

Many mistakenly believe that the 'lead' in gasoline somehow acts as a lubricant - when in fact the lead causes a chemical reaction that locally hardens the seats as the engine is run:
SBI International
and that one doesn't even need a steady diet of leaded gas. Once the seats are hardened one can switch over to unleaded gas with no ill effects.

So what should I do with my 216:

1)Take a risk with a machinist and an aftermarket hardened seat
-or-
2)Run lead additives or lead substitutes until local hardening takes place during break in?
Redline Oil
STP

For me choice two seems less risky. Especially since we're talking about a car that will be driven less then 1000 miles per year; won't be used for towing; won't cruise for hours and hours and hours on the freeway . . .

regards,
stock49

P.S. Some interesting reading on gasoline:
Gasoline FAQs

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