Quote:
Originally Posted by Tom Wesenberg
By "inserts" I hope you don't mean you want to install valve seats. I would only do that if it is REALLY needed to correct excess recess of the original seat.
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I'm rebuilding an engine that has a significantly burnt first cylinder exhaust valve, valve seat, and even the piston is burnt closest to the valve. I had the same problem on my own Model A years ago.
I'm told unleaded gas is tough of the exhaust valves because it burns hotter. I have no data to support this, but the new valves are stainless, and stainless inserts don't burn like the stock block does in my experience.
I have no idea why it's always been the first cylinder. Maybe leaner?