On spark advance from an old-timer.
Correct spark advance is a matter of experience and experimenting. Every
engine set up differently will need different advance. Some setups are so
similar that they take the same advance. When I used to run my 8:1 ARDUN
with the plugs somewhat recessed I set it at 52 degrees(!) with 10 pounds of
boost or unblown. I worked up to that number gradually. Now that this one
is 9:1 with better quench 42 degrees seems good blown and unblown. My 12:1
ARDUN with unshrouded plugs likes 36 degrees. My flatheads like 28 degrees
when there is a lot of clearance between head and piston. If the clearance
is tight or the blower in attached they like 22 degrees. Some guys run
flatheads at 10 degrees. The engine tuner becomes the expert on spark
advance with experience.
Dave Thomssen
#322 XXFSTR
The Hayseed
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