Ignition timing advance/retard

[Tony Griffiths]

Hi Tony

It is the variation in noise level that gives that effect. On my RP could shift over a huge range; engine noise level varied enormously  but  the top speed remained  the same. Manual advance gives you something to while away the time when climbing...or accelerating. With wear and springs of uncertain providence never really sure if auto advance is optimal (ie just as much as necessary for performance.)  
For cars converted it is worth retaining the manual as an override. Enables the optimum setting without use of the kitchen clock. A light spring on th linkage eliminates backlash.
Influences hill climbing more obviously.

Hi Bob, yes, the coil spring - I'd forgotten that I too, at one time, used one for that effect. The other trick was to replace the 'shouldered bolt with spring' with an ordinary one and tighten it down just sufficiently so the distributer could still rotate - but with the slight up and down movement eliminated. A drop of light-duty Loctite on the thread ensured that the bolt stayed put.