Clifton Posted April 8, 2005 Share Posted April 8, 2005 Some early 280 heads, can't remember the number, have bronze intake seats. They get pounded in till you can no longer adjust the valves. From what I understand is that lead is used to lubricate the valve guides and has nothing to do with the seats. Quote Link to comment Share on other sites More sharing options...
cheftrd Posted April 9, 2005 Share Posted April 9, 2005 Some early 280 heads, can't remember the number, have bronze intake seats. They get pounded in till you can no longer adjust the valves. From what I understand is that lead is used to lubricate the valve guides and has nothing to do with the seats. Steel and bronze are ferritic and non-ferritic metals respectively. They won't bond and no errosion (valve-seat recessione) will occur. That's why high end race engines use beryllium seats. Bronze can be super hard. Lead in gasoline is used as a "lubricant" (in addition to being an octane booster) for the valve seats for the reason I gave above (it keeps the valves from sticking to the seats. Oil lubricates the valve guides. As for the E31 head; so the seats were cut right into the aluminum and that's what the valves closed against? I think not. They had inserts installed. The inserts were not machined out of soft cast iron. They are made of a steel or bronze alloy, either of which does not require lead to keep them from erroding. This is not opinion, it's fact. SAE stands for Society of Automotive Engineers (of which I am one). Of course, you're free to disagree Check it out: http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=5635342 Quote Link to comment Share on other sites More sharing options...
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