Mag + Lightspeed plug wires

Top & bottom is not critical; Cylinder number IS.

EI on lowers?

Mel.. while it might not be critical, I thought the preferred method was to put the Electronic Ignition on the lower plugs.

Since the lowers tend to foul more than the tops when using two mags, the hotter spark of the EI systems is then more useful when it is wired to the lower plugs.

Is this still the current thinking? ...or does some other logic prevail?

gil in Tucson

Gil,

I totally agree with your rationale but did the opposite.

By mounting my LSE coils on top of the case, and by running the wires to the top plugs, and by running my single Slick mag wires to the bottom plugs, there didn't need to be any baffle penetrations for plug wires. Easier setup all around imho.

I haven't had a fouled plug in almost 1000 hours...never with this setup. Possibly notable is that I use UREM37BY plugs on the bottom. Apparently a less foulable design. Haven't run any other type of plug in this particular engine, so I have no basis for comparison.

I also use the UREM37BY. And when I had EI, I had it on the bottom plugs for just that reason. However the Lightspeed ign I think specifies the top plugs.
My comment about the top & bottom wires not being critical was for the mag wires. The harness is marked 2-up and 2-down so that if the lower plugs fowl, they won't all be on the same mag. My point was that if a mag is connected to all the top plugs or all the bottom plugs, the engine will run just fine.