I'm running an excel/dfi ignition system with an MSD tall deck distributor on a quad rotor 540 at 6400rpm. Problem is every 5 hours or so the msd rotor burns up. Is this just a quality issue or should I look elsewhere?

from what I've experienced with that type of set up is you rotor is phased in to far before the terminal and many times it will burn to one side of the rotor terminal because the spark has to jump very far if this is what is happening what I do is use an Accel dual sinc dist which you can adjust internally for sinc with the top and the bottom pick up the dist is not that expensive and believe it or not the engine runs better with that dist because the spark is alot more accurate. Also cheaper way to go is to pull the MSD apart and reposition the pickup in the right phase point by drilling the shaft and realigning. Please let me know how that works out and if you have any questions call me 1-305-884-5368 Sincerely yours Laz

As Laz says it is a phase problem, but it is possible the cause is the mag pickup wires are reversed.

The engine will run much better once you get this fixed !

As a quick fix I'll like to try and reposition the pick up. Before buying a new distributor. How would you know what the correct phase point is?

We take an old cap, cut the side off and run the engine so you can see where it fires.

Definetly a rotor phase problem. When I set-up timing on a car motor with a crank trigger, I use an old cap with holes in it by the electrode. Then hook up a timing light to the wire where the hole is, run the engine and position the distributor. Ofcourse, with a crank trigger system, this has no effect on the timing, only change is the rotor phase. On yours, you would have to reposition the pick-up. Give me a call, I can explain better than I can type. I hate typing.