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What good is the part of the ramp the rocker/follower never sits on?
Same Smith of Design and Tuning of Competition Engines?
Hello Walt,
Less acceleration and noise, like the quieting ramps that Jaguar developed in their parabolic cams to reduce noise at double and triple the earlier non parabolic cam clearances. Not a performance issue, a marketing response to the hydraulic lifter.
Same Smith, his +200 page tome on the poppet valve has been out of print for a while. I had to buy a zerox copy from a peg legged pirate 25 years ago. It has every wacky idea tried until 1967, and gets into the valve temperature and expansion rates of the sodium filled valves of the last of the highest spec piston aircraft engines before the jet took over. There is some recent work trying to understand the heat transfer at the valve seat, the finish of the surfaces, the mysteries and the mechanisms involved, but you can find a similar discussion on page 800 of the "Modern Gasoline Automobile of 1916". This book is truly amazing and I'm sure Harry Miller had one in his pocket.
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Paul
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