Thanks Mark for the idea about putting foil over the Tiny Tach sensor wire where it wraps around the lead. I didn't run a new ground but just tightened up the wraps and cut a piece of aluminum tape and covered the wraps and the Tiny Tach is back to normal. This the first time that either of the two Tiny Tachs I've owned have ever done anything weird.
Sorry if I've confused anyone regarding my comments last post about plug gaps and concern about coils getting old, etc. That's what comes from not having my head in the game for the last couple years. I closed the gap on the secondary plug on the cylinder that was missing and figured I'd solved the problem without realizing the .016 - .019 gap range I mentioned is for the magneto plugs, not the secondary plugs. Now I KNEW that electronic ignition plugs take a much wider gap than the magneto plugs, but totally forgot that yesterday when trying to track down the miss. (Things like that is why I've got the plane up for sale.) The secondary plugs, looking back in my engine log, I originally gapped at .030. Forgetting that yesterday, I totally mistakenly jumped to the conclusion that the large gap on the plug was due to electrode wear . . . and that's what I passed on to everyone yesterday. (A good example of how misinformation gets started and passed around on the internet.) That the engine ran without missing once I closed the gap to .015 was incidental. The green coils from Great Plains are built by Dyna and designed to fire a .040 gap. Closing the gap to .015 should not have fixed anything. I probably "fixed" the problem by accidentally moving a lead wire around so that it wasn't touching another wire or the engine mount - something giving it an opportunity to arc - which is what I now think the source of the miss was. The Dyna coils are putting out 30K volts and the leads need to be well-insulated and in good shape. Mine have been on the plane forever, so it's time for some new harness wires. Thankfully, the leads are not molded into the coils as some cheaper systems do it. The wire leads off of the Dyna coils are removable so I'm now shopping for some new ignition leads. Great Plains sells them for $30 but gives no details about whether they are resistor or non-resistor leads. Are the spark plug caps they come with resistor caps or non-resistor caps? What kind of wires are they anyway . . . silicone, copper, something else? Who makes them? Great Plains doesn't make them, so who does, and what are the specs? These wires aren't for a damn dune buggy, they're for an airplane so why the dearth of detail? Are we presumed to be too stupid to want to know what we're buying? Same thing with the plugs they sell for the secondary ignition system. They're described as 10mm plugs. That's it. No brand. No info whether they are resistor plugs or non-resistor plugs. Nothing regarding heat range. We need pretty cold plugs in VW engines so just what is the heat range? I'll call later in the week after this holiday stuff is over and see if Marty knows the answer to these questions but really, I shouldn't have to waste his time with questions that the catalog should have already answered. BTW, if the current GP catalog is accurate, they've got brand new Slick 4022 magnetos for $375!! These are exact replacements for the 4316 that Spruce is selling for $1133. Last time GP had these they ran out quickly so get 'em while they have them as the opportunity may not come again. They're surplus industrial mags that are green instead of black but are otherwise the same and have been machined to fit the Diehl case. Thanks to Sparky I happen to have a brand-new Slick in reserve or I would be ordering one of these green ones tomorrow. Mike KSEE ____________________________________________________________ The #1 Worst Carb Ever? Click to Learn #1 Carb that Kills Your Blood Sugar (Don't Eat This!) http://thirdpartyoffers.juno.com/TGL3141/5564035e4218535e55b8st02vuc
