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Re: Ign timing; advance vs retard
> I wanna make sure I've got this right. Without delving into the myriads
> of reasons why (relative angle of crank/con rods; varying values of com-
> bustion burn rate depending on instantaneous cylinder pressure; etc, and
> so forth) the ignition timing is a variable, one "advances" the timing
> by causing it to fire earlier in time, or at a "larger" BTDC value, cor-
> rect? I.e., 10 deg BTDC is 'advanced' timing relative to 5 deg BTDC?
So far it's 3:
Yes, you have it correct. Another way of looking at it, is to
graph piston position with respect to time. It will look roughly
(exactly?) like a sine wave, with the very top being TDC. Anything that
happens before that top is called before top dead center, or BTDC, so an
event that happens at a greater number BTDC is more advanced.
Correct. BTDC =3D Before Top Dead Center in degrees so a larger BTDC =
numeric value means 'sooner' as opposed to 'later' or advanced as =
opposed to retarded.
Correct. As spark happens earlier, or more "in advance", timing
(plus my vote, for a total of 4) to 1:
Thats retarded (The timing that is). Advancing it would be a positive
change. i.e. 2 deg BTDC is advanced relative to 5 DBTDC
You're outvoted, Bob!