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Sep 18, 2015 2:55 am
Sep 18, 2015 2:55 am
Subject: Re: BT-H Magneto CE6
My reprint of a Scintilla manual notes that the magnetos deliver two sparks per rev, so a six cylinder magneto has to be driven at 1.5 times engine speed. It also notes that for engines working on a two stroke cycle, twice as many sparks per revolution have to be delivered. They therefore made magnetos marked MN4 1/2, GN4 1/2, MN6 3/4, and GN6 3/4 with 4 sparks per rev, so they can be driven at the same engine speed as the conventional magnetos on four stroke engines. I suppose you could run one of these special magnetos on a four stroke - you would adding a spark just as the exhaust stroke was finishing, which I don't think would do any harm.
The gearing inside the magneto is to match the magneto speed to the distributing rotor, so it would be 2:1 on a four cylinder and 3:1 on a six.
I'm getting this information from the manual - I don't have a PN6 to look at as my car has a more modern Fairbanks-Morse.
Alec
My reprint of a Scintilla manual notes that the magnetos deliver two sparks per rev, so a six cylinder magneto has to be driven at 1.5 times engine speed. It also notes that for engines working on a two stroke cycle, twice as many sparks per revolution have to be delivered. They therefore made magnetos marked MN4 1/2, GN4 1/2, MN6 3/4, and GN6 3/4 with 4 sparks per rev, so they can be driven at the same engine speed as the conventional magnetos on four stroke engines. I suppose you could run one of these special magnetos on a four stroke - you would adding a spark just as the exhaust stroke was finishing, which I don't think would do any harm.
The gearing inside the magneto is to match the magneto speed to the distributing rotor, so it would be 2:1 on a four cylinder and 3:1 on a six.
I'm getting this information from the manual - I don't have a PN6 to look at as my car has a more modern Fairbanks-Morse.
Alec