Ford edis with megajolt

[Kirk Harrell]

Originally Posted by CATPart

Stepping back to the configuration with no megajolt, and 2 reluctors spaced to give you two different timings, switching between reluctors.....I wonder what the EDIS thinks when it sees this switch event. The switch could cause a momentary signal dead spot, or could provide 2 TDC indications within one revolution, or could cause a voltage spike if the signals combine, etc. The switch event may have to be carefully scoped and tested, and maybe buffered out with some simple circuitry.

This is my first post to this forum. May take a while to get things right. This is Kirk Harrell.

The second reluctor is for ignition #2.

Ignition #1, the reluctor is clocked to provide TDC cranking fire (but doesn't really; more like 3 degrees BTDC) and EDIS only 10 Degrees advance limp home timing without the controller. Ign #1 is married to the Megajolt and provides rpm and manifold pressure controlled advance.

Ignition #2 is not energized for engine cranking. The reluctor is clocked to fire the plugs 15 degrees BTDC at cranking speeds. The EDIS advances 10 at about 300 rpm and remains fix at this setting. This will provide duplicate spark timing like a normal 25 degree fixed mag with the advantages of hot spark, wide plug gaps of EI.

Switching the electronic ignition off. I have done this before every flight with the standard mag check. About 75% of the time the engine just gets happy again when Ign#1 comes back on. Another 24% of the time the engine stumbles slightly, like the controller takes a nanosecond to find itself. 1% of the time it seems to take just slightly longer. Same thing in flight.

The mag check goes from left ign to right and back. If the EI takes a split second to find itself it will sometimes reward you with a nice bark! Have you ever accidentally killed both mags, then switched back on real quick? Yeah, like that.

[CATPart]

Hi Kirk,
I guess I had somewhat misunderstood your system. But at the same time that got me thinking of switching between reluctors in order to achieve a 4° ATDC like pmag does for starting, using no megajolt. This would be on both ignitions, so everything is a duplicate and redundant. So my worry was about how the edis would handle the switch between reluctors. The fact that you say your mag check can cause some popping and crackling makes me think something similar would happen with a system as I describe. I am trying to get the easy starting for a lightweight prop, without using any megajolts anywhere in the system. Its just a thought experiment for now.

Lets pretend we have a pair of identical mag hole triggers, each with reluctor #1 at 4° ATDC and reluctor #2 at 15° BTDC. You start up on reluctor #1 which gives you 4° atdc below 300 rpm. Once the engine starts and rpm increases the ignitions advance +10 to 6° btdc. Now you flip the switch to the #2 reluctors and the ignitions settle out at 25° btdc.

[Mike S]

Originally Posted by Kirk Harrell

This is my first post to this forum. May take a while to get things right. This is Kirk Harrell.

Kirk, welcome aboard the good ship VAF.

Great to have you here

[Kirk Harrell]

Lets pretend we have a pair of identical mag hole triggers, each with reluctor #1 at 4? ATDC and reluctor #2 at 15? BTDC. You start up on reluctor #1 which gives you 4? atdc below 300 rpm. Once the engine starts and rpm increases the ignitions advance +10 to 6? btdc. Now you flip the switch to the #2 reluctors and the ignitions settle out at 25? btdc.[/quote]

[Kirk Harrell]

The EDIS counts Nine teeth after the skipped tooth and initiates ignition. I can't think of a scenario where switching reluctors would cause it to fire abnormally early. Maybe a little late, but not too early.

IMO the greater risk would be forgetting to switch back to the "starting"reluctor. This could be defeated with a DPDT relay that switches pick ups when the starter is energized.

[DanH]

Originally Posted by Kirk Harrell

Switching the electronic ignition off. I have done this before every flight with the standard mag check. About 75% of the time the engine just gets happy again when Ign#1 comes back on. Another 24% of the time the engine stumbles slightly, like the controller takes a nanosecond to find itself. 1% of the time it seems to take just slightly longer. Same thing in flight.

Kirk, I don't recall...for a mag check, when you kill the EI, are you killing coil power, or EDIS module power? Either way, it's not an interruption of the reluctor signal, which seems to the subject here.

I kill power to the Megajolt/EDIS/coil, as a group (wiring diagram in post #4). No stumble or oddity when switched back on.

[Kirk Harrell]

Yes, same here. All power off. Where we are different is switching. You are using two toggle switches. I am using the standard "left, right, both, start" ignition switch. When you mag check you go from 'both on' to 'one on' back to 'both on' every time. When you re-energize the EI the other ignition is still firing away. Any split second delay while the EI finds itself is masked by to other ignition.

When I mag check the switch I am using goes from left to right. The right ignition kills as the left ignition energizes, and visa versa. Any split second reorientation by the EI is not masked by the other ignition. And sometimes, no fire for just a split second fires any unburned fuel that got past the exhaust valve. Pop! Again, this is maybe 1% of the time.

[6 Gun]

Kirk do you think the ring gear could just as easy with all the screws be split to go on and off easy?
Bob

[Kirk Harrell]

Dan and I discussed yesterday mods to his early print from which I cut the ring. A split and a mounting hole at every tooth would serve several improvements. Lighter, easier on and off and more flexibility for clocking on the flywheel to aid in crank sensor mounting.

One thing to remember is the missing tooth needs to be balanced. I hung the assembled unit on a sensitive prop balancer and added longer bolts and washers where needed. I suppose one could static balance the ring on a mockup plate and transfer balancing hardware to appropriate flywheel locations. But with a multitude of mount holes to choose from, you would have to figure out which holes you are going to use first.

Alternative, dynamic balance ASAP after installation.

I must say that Dan is a great resource. **** near brilliant, he questions everything. If he doesn't know the answer he learns the answer. He questioned my pickup application. So, hold on before making a ring from the drawing he first shared. I think he has trigger wheel ver 1.1 in the works.

[Mike S]

Originally Posted by Kirk Harrell

So, hold on before making a ring from the drawing he first shared. I think he has trigger wheel ver 1.1 in the works.

Yep, he does.

Anybody out there know if the 360 and 540 use the same flywheel?