Netters The 8 plug 4cyl head design is to increase the flame for more complete burning. The Nissan does not fire on exhaust stroke but does fire simultaneously with the first. Many times to find a malfunction in the primary firing I have exchanged the coil conections and the engine ran great. The computer uses both a speed sensor and rpm sensor amoung other things to keep both firing or drop the second plug and only fire the one primary side, as in during light loading during cruise. Under load they all fire. They use 2 different pickups, one module, and 2 coils, so almost a dual ignition complete. They are also designed for 2 different heat range plugs, the exhaust being one heat range cooler to prevent detonation/preignition issues.
The Ford 8plug head use a DIS system, and fires both on compression stroke, and exhaust, referred to as waste fire ignition, which is for simpler ignition programming, and better emissions. This system has no back up, as 1 ignition module, crank trigger, cam trigger, but 2 coil packs or CD (Capacitive Ignition Coils), and 2 sets of plugs and wires. The Ford is not available in carb models but only sequential fuel injection, so if not your game, will be very complicated to retro into an aircraft. Check Summitt Racing, Jegs Racing, Mallory, MSD, and Crane Cams for ignition systems that may easily adaptable with alot less work. Pick up any issue of Hot Rod Magazine and you will see adds for them. Also, look in Front wheel/ Import performance magazines for the latest in adaptations and options. There are literally tons of aftermarket stuff for use "off road" for the performance enthusiast. Colin & Bev Rainey KR2(td) N96TA Sanford, FL crain...@cfl.rr.com http://kr-builder.org/Colin/index.html
