when did valve overlap originate?

The first internal combustion engines did not have exhaust and intake valves open at the same time. When did it occur to somebody that overlap would improve performance, and when was this adopted by all engine makers? (I am not considering modern variable camshaft systems, just the basic fixed camshaft 2 valves per cylinder stuff).

Reply to
bruce56
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FWIW, valve timing issues such as overlap were discussed in a 1920's manual that can be seen at

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on page 95

Reply to
Retired

Wow! Nice wealth of info on this ng.

Reply to
Paul in Houston TX

afaik, it was this guy that started it all - the peugeot l45. the

4-cylinder 16 valve dohc motor with integrated head that offenhauser "used for inspiration" on their winning designs.
Reply to
jim beam

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