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poppet valve specs
Posted by: Peter Heid (IP Logged)
Date: June 26, 2003 09:40PM
<HTML>Having worked in an automotive machine shop for several years, I have seen many different specifications for the valve and valve seat contact faces. Face angles can vary from 15 to 45 degrees and the seat width specifications are just as varried. I know in an IC engine, seat width is most associated with the need to transfer heat to the seat while it is closed. The face angle is based on loading by the springs, valve and seat materials and the need to increase contact width (cooling again) but mostly by the engineers preference. Most of the tools to machine valves and seats will leave an interference angle of 1/2 a degree, allowing the outer edge of the face angle to contact first. This is not recomended for LPG vehicles though and they are machined with matching angles.
As I prepair to install seats for single poppet valves, I was wondering the best face angles and seat widths to use and would it be proper to machine with an interference angle or not. I have specifications for large marine engines of low RPM and reletively heavy valves, but nothing for light high speed steam engines.
Peter Heid</HTML>
As I prepair to install seats for single poppet valves, I was wondering the best face angles and seat widths to use and would it be proper to machine with an interference angle or not. I have specifications for large marine engines of low RPM and reletively heavy valves, but nothing for light high speed steam engines.
Peter Heid</HTML>
Re: poppet valve specs
Posted by: Terry Williams (IP Logged)
Date: July 04, 2003 07:49PM
<HTML>I use 45 degree valves and usually use a half degrees interference. Have not noticed that the 1/2 degree makes any difference , but have not made any extensive tests.</HTML>
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