Originally Posted by
A Squared
OK, going back and reading a few earlier posts I'd skipped over previously:
Not sure what your point is here. You seem to be trying to suggest that all those tolerances can stack up to throw your timing off even more. Not true. The internal timing of the magneto (e-gap or point gap) only determines where the spark fires at the optimum time in the field rotation, it has nothing to do with where that happens relative to the crankshaft rotation. That is determined solely by the magento-to-engine timing. (ie: rotating the magneto on the accessory case so that point opening happens at a certain crankshaft angle) If your magneto is timed so that the points open at 22 deg. BTDC, it really doesn't matter whether your e-gap is set at 13 degrees or 17 degrees, the spark still fires at 22 Deg. BTDC. The e-gap setting only determines the efficiency of the spark generation. (that's what the "e" in e-gap stands for; efficiency)
Jeeeez dude. Are you not reading anything? He told you how he knew. He Noted higher than normal CHT's on climbout, did an airborne mag check, noted a difference from one mag to the other, then when on the ground, checked the timing (as we later were told, using a Mag-rite electronic protractor set-up) and found one of his mags to have been set to 25 degrees BTDC.
Mate,
A) there is the mag to engine timing tolerance of +/- 1 degree (it was my first point in that list) but within this rage will give indication changes.
But not timing incorrectly!
B) all other variable parameters listed will change the actual spark and its intensity.
A wider spark plug gap will slightly delay the spark (greater gap more resistance - more spark power needed)
You also will find plugs make a big difference to engine ops - spend the bucks on some fine wires and compare them to the massive electrodes.