Timing, Heat and A/F ratio?

[Woods]

(Nice features Jay, especially the spell checker.....opps, it isn't there!)

Now the questions. some spec's 240 @ .050  108 LSA, 10.2 to 1

Heat; I've noticed that with less initial timing, idle heat is higher.  On my 445, 10 degrees is hotter than 12. (195 @ 10, 180 @ 12) in addition I can get a smoother idle at 10.  Is 12 to much?

Air Fuel ratio;  Is there a relation ship between optimum timing, carb tuning and the resulting A/F ratio?  If I've tuned my carbs for the best idle and A/F, will adjusting the timing have an affect on the A/F and how much.

Thanks for any comments,
Woods

[jayb]

Heat; I've noticed that with less initial timing, idle heat is higher.  On my 445, 10 degrees is hotter than 12. (195 @ 10, 180 @ 12) in addition I can get a smoother idle at 10.  Is 12 to much?

Air Fuel ratio;  Is there a relation ship between optimum timing, carb tuning and the resulting A/F ratio?  If I've tuned my carbs for the best idle and A/F, will adjusting the timing have an affect on the A/F and how much.

Twelve degrees of initial is not too much in my opinion, and I've run as much as 20 myself.  More timing will generally make the engine run a little cooler, at least to a point, so that is no surprise.

I think your A/F will be affected by timing, since the timing will affect when and how completely the mixture burns.  There is an optimum timing point for any engine, and once you think you've got it dialed in, that's when you should be jetting to get the proper A/F.  Small changes in timing probably won't have a noticeable effect on A/F, though, so if you are talking about going from 10 to 12, I doubt you'll see much of a difference.

Hope that helps - Jay

PS - spellchecker is now enabled!