More forwards and backwards

The closer I get to the goal, the farther away it gets - at least, sometimes it seems that way.

My current challenge is getting the electronic timing correct, then to program in the mixture "map". To map the mixture settings with the RWS EC3 Electronic Control Unit (ECU), you will input a setting for each 1/2" step of manifold pressure; from idle, all the way to full throttle. You use the fuel/air gauge to determine what the mixture is, at that throttle setting.

This ultimately provides a look-up table for the ECU for any given throttle input.

Before I do that mapping process, I need to get the base ignition timing right. This consists of making a sole timing setting, the "base" timing. In my case, since I am using 9:1 pistons, it will be 25 degrees BTDC, with the engine at full throttle. By simply pushing a button, you use the ECU programming panel to advance or retard the timing.

So that's the theory. The reality of it all becomes more difficult, at least, for me.

First thing is the working conditions. While southern Illinois is hardly the coldest place in the nation, I am getting tired of winter.

I first tie the tail down to a front wheel of my car to keep it from going anywhere. In order to perform the timing, I have to beg a volunteer to come out and run the throttle for me.

In the above photo, (click to see it bigger) you can just see the toothed timing wheel, just aft of the propeller spinner flange. I mark some of the teeth for timing reference. Then I have to hook up a timing light and have the volunteer run it up to full throttle. I lean over the engine and hold the timing light within two inches of the spinning buzz saw. Since it's pretty bright outside I even have to shade the timing marks with my other hand so I can see the strobe flash. I actually kind of rest the side of my hand on the aft end of the spinning prop extension. I'm not sure that OSHA would approve.

I have to wear two jackets, goggles, hearing muffs and a hoodie to keep myself together. I calculated that at 35 degrees and 100 mph of prop blast, the windchill is 14 degrees. But that is really only half the fun. The other, is the sensory kick I get from the combination of the prop blast, the major engine vibration and noise, the snot blowing out of my nose fogging the goggles, and the inherent danger of working around those spinning parts.

So, after repeatedly (10 times?) doing all that, we found a few discrepancies. One, I made the sensor mounting bracket wrong and will have to re-do it. Two, for some unknown reason the engine runs worse when the timing is in the right place. Three, my digital tach bounces around so much I'm not really sure what it is telling me.

So whine, bitch and groan.

But, at least I keep working on it, and I guess that's progress.

Thanks, today, to John Eynon for patiently running the throttle for me.