Ford edis with megajolt

[DanH]

Two photos to clarify coil wiring, 4 cyl of course, 6 cyl conceptually similar.

These are coil packs, two coils packaged together. Each coil has two spark plug towers, as each coil fires two cylinders at the same time, every time those cylinders approach TDC.

Early coil. Uses a plastic retainer for positive retention of the plug lead cap in the tower. Bottom isn't flat, so it must be mounted on standoffs. This fancy blue one is aftermarket. When viewing the bottom, the individual coils are really obvious.



Late style coil, also familiar to P-mag users. Taller towers, flat cast epoxy bottom. Here the individual coils are obvious from the top.



The pinout is logical, and the same for both types. Power is supplied to the center pin. The EDIS module's coil driver circuits switch coil ground, on to build a magnetic field, off to cause a spark. Each coil is controlled by the pin closest to it, with EDIS pin 10 being (in our engines) cyls 1 and 2, an opposing pair.

These are Ford OEM or aftermarket coils specifically intended for EDIS, but I'm pretty sure the EDIS module will fire any similar waste spark coil without an internal coil driver. The module incorporates coil current limiting. I happened to do some measuring recently. Early style coils appeared to be fully saturated, and spark duration with new IKH27 plugs stock-gapped at 0.8mm was 22~24 degrees in the cruise RPM range.

[WingsOnWheels]

Dan,

That is an excellent post on the coils, thanks. In general, the megajolt manual is a little light in this area.

I ended up using the late style coil. The early style would be a better fit for my installation, but I was having trouble finding boots and retainers to match the MSD superconductor wires.

For the late model coils, boots and terminals sold for LS1 coils work perfectly. I was concerned about retention, but the boots hold onto the towers aggressively.

[WingsOnWheels]

My EDIS system is working very well so far. I have about 2 hrs of flight time (plus about an hour of ground testing). I haven't been able to do full performance testing yet, focused on functional checkout at this point. The most obvious observation is much easier cold and hot starting. That is a huge difference. ~40f OAT and starts in 1-2 blades at most. Startup is also very smooth as Dan noted earlier in this thread. Since I am still running the mag on the left side, there is no advantage gained by the reduced advance during idle.

At first look, switching from flat to modified curve in cruise buys about 30rpm (fixed pitch). I now have to be careful since I can exceed 2750 rpm at higher altitudes than before. I think my Catto is a little underpitched for max speed.

More testing to come. I am already working on the hardware for a second system, but need to lay out a solid electrical plan before going to two EIs.

[bh540]

[quote=DanH;1060769]Bob, almost anything which provides 35 teeth and a skipped tooth space will work. The Lycoming flywheel has 12 AN4-sized mount points, so for a first pass, I drew this, and Kirk (that's Kirk Harrel, the Mustang II owner) turned it out on his mill. It's a steel plate, 3/16" thick IIRC, cut on a rotary table. It would be real easy to do on a waterjet; hand the operator a .dwg file and a few bucks. Flywheel = gray, trigger wheel = white. A standard Ford pickup points forward (at the sides of the teeth), much like the mount you've seen for hall effect triggers. Note small alternator pulley.



BTW, a little design tweaking would save weight, but for those who have rear CG concerns, well....
I really like the position sensors shown in this picture , They look a bit more robust than the ones I have been able to locate does anyone have a source or part number for these?

On Kirk's Mustang II:



Make the tooth width the same as the width of the tip of the pickup; that nets a clean sine wave signal for the EDIS module. See the blip on the right? That's the passage of the skipped tooth.

[/QUOTE
]I really like the position sensors shown in this picture , They look a bit more robust than the ones I have been able to locate does anyone have a source or part number for these?

[DanH]

New OEM Ford parts, common as dirt. Or any wrecking yard for pre-loved.

Or, https://www.autosportlabs.com/produc...jolt-ignition/

Or, these are Standard Motor Products part numbers. Most auto parts outlets can cross them over to their store brand.

CONNECTORS
S-744 edis module pigtail
S-755 coil pigtail
S-812 crank and cam sensor pigtail
S-674 tps pigtail

SENSORS (Ford style)
PC19 VR sensor angled forward
PC51 VR sensor angled down
PC74 VR sensor straight
PC27 VR sensor cam type

MODULES
LX239 EDIS-4 module
FD-487 coil pack

You can go to www.smpcorp.com and enter the part numbers to look at the parts. This is particularly helpful when picking a VR sensor.

I have not found an equivalent for the EDIS-4 or EDIS-6 module pigtail. It seems only the S-744 EDIS-8 pigtail is available. You can still use the S-744 of 4 and 6 cylinder modules but you'll have to cut some of the connector's keying features away to use it.

[bh540]

Thank you very much! very helpful!

[WingsOnWheels]

Originally Posted by bh540

Thank you very much! very helpful!

I bought my EDIS-4 module with the connector (cut-off harness) and was able to buy new pins so I could properly re-pin the connector and not have to cut off the key. The connectors are very easy to disassemble.

[bh540]

I was able to locate some NOS edis 6 modules And I ordered the connectors from standard
Do you have a part number and source for the new pins?

[WingsOnWheels]

Originally Posted by bh540

I was able to locate some NOS edis 6 modules And I ordered the connectors from standard
Do you have a part number and source for the new pins?

I bought them off a guy that sells the new EDIS8 connector kits on ebay. He was willing to sell the pins separately. They were cheap enough ($8 shipped for 15) I didn't bother digging further. His e-mail is paulplasmaphone at gmail