The Ford Barn

Barry in St.Paul · 06-07-2010, 09:39 PM

OK, at the risk of sounding really ignorant, I'll ask this anyway; why is it so important that the timing be so absolutely perfect on a Model-A? I understand the importance OF the timing, but with a Model-A, you are constantly adjusting the spark lever anyway, and I seldom run it fully advanced even at road speeds.... So, seems the key aspect would be that the spark is retarded-enough when starting, so as not to damage the engine with a backfire...?? So I wonder, how does setting the distributor cam (ie: timing) "just right" affect engine power or anything else, since you can move the spark lever to compensate to where-ever that sweet-spot is for your engine?
It's one thing to be really anal about something like bearing-shims and such, where "they are where they are, and will stay that way!". But I don't quite get the ongoing debate about a few degrees this way or that for the distributor cam. What am I missing? Is it the "full-retard" position that is very critical, for starting? (and if so, if my engine pops off with just a turn or two of the engine, does that confirm 'good timing'?)
Just curious. Easy enough to do again and again and get "just right", but I've often wondered while I'm doing it, what difference it really makes, within reason.
thanks!

06-07-2010, 09:39 PM	#1
Barry in St.Paul Senior Member Join Date: May 2010 Posts: 118	Timing; why is being 'dead nuts' so important? OK, at the risk of sounding really ignorant, I'll ask this anyway; why is it so important that the timing be so absolutely perfect on a Model-A? I understand the importance OF the timing, but with a Model-A, you are constantly adjusting the spark lever anyway, and I seldom run it fully advanced even at road speeds.... So, seems the key aspect would be that the spark is retarded-enough when starting, so as not to damage the engine with a backfire...?? So I wonder, how does setting the distributor cam (ie: timing) "just right" affect engine power or anything else, since you can move the spark lever to compensate to where-ever that sweet-spot is for your engine? It's one thing to be really anal about something like bearing-shims and such, where "they are where they are, and will stay that way!". But I don't quite get the ongoing debate about a few degrees this way or that for the distributor cam. What am I missing? Is it the "full-retard" position that is very critical, for starting? (and if so, if my engine pops off with just a turn or two of the engine, does that confirm 'good timing'?) Just curious. Easy enough to do again and again and get "just right", but I've often wondered while I'm doing it, what difference it really makes, within reason. thanks!