In a message dated 12/14/2005 4:22:53 PM Eastern Standard Time, montyr2157@alltel.net writes:
Lynn,
What is the "hot" set up for MSD. A 6AL box with two coils on the leading plugs with wasted spark? I plan on using a magneto on the trailing plugs. What about advance curves? Vacuum advance and the like. I really don't want to run a distributor for clearance reasons.
Never have run an MSD so I don't know a whole lot about them.
Monty.
No distributor is needed.
The MSD 6T for dirt circle track service is what we started with, but switched to the 6AL because the rev chip plugs into the side of the main box, instead of a secondary box with a cannon plug. The 6T is potted for strength is the other difference.
If the funds are available to have a 4 cylinder Mag on the trailing plugs, then I would rig up a drive for any real aircraft Mag and grind off two of the points cam lobes and spin the Mag at crank speed with a little toothed belt. The trailing must be distributed because one trailing chamber is mixture laden and is exposed to the plug when the other is firing.
Guys, DO NOT use a 4 cylinder AIRCRAFT mag for any high RPM service. Some years ago motorcycle guys tried just that at Bonneville. They figured that the mag didn't need an eletrical system so it would, "Be lighter, faster, more powerful, insert your favorite adjective." The magnets in the MAGneto were not phased or designed for 8K rpm and actually started misfiring at high RPM's. They found a battery and some points to throw in and went 20 MPH faster running total loss. Unless the aircraft mags have changed a lot, ( and I'd bet against that), stay with a MSD throughout. FWIW
Bill Jepson