justin_o_guy2 wrote on 09/03/12 at 23:27:08:The reason there is slack in the valves when its cold is, the valve stems get longer when they get hot. That closes the gap up some,.The tighter ya set the valves, within spec, the quieter it is.
not quite right, Sir! Since valves and rockers always have to have some clearance, just to assure the valve springs can close the valves everytime they have to.
In fact the construction in the S40/Savage is that way, that valve clearance increases with increasing temperature of the enginge parts.
Not alone the valve stems get elonged on higher temperatures, the head material (aluminium) does, too! And the thermal expansion coefficient of aluminium is more than twice than steel.
Thsi should make clear facts, that "Elsie" usually has the valve ticking sound louder when she is hot. The head is made of cast aluminium and therefore it lifts up the camshaft more than the valve stems can elongate.
Back to S40: The specs say a clearance ,08 mm to ,13 mm.
,10 mm is a good middle course. It should be more of concern that both valves are at very same clearance than exactly ,10mm.
Intake may be adjusted with lower clearance since they do have lesser temperature stress.
There may be different construction features in other engines, where valve clearance decreases with rising themperature. Then they mostly are designed to have adjusted valve clearance at operating temperature or, assuming the difference to room temperature is well known, the valve clearance can also be adjusted to a greater gap when "cold".
We had some odd apperances and experiences with that theme on different engine types when I was in apprenticeship on Volkswagen, Audi and Porsche back around 1980
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