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Ford edis with megajolt

I am making an assumption here that the Slick bearings generally run to TBO without failure.
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Not a good assumption. Slicks requires a 500 hour inspection; That is their TBO, though the requirement is IRAN and not overhaul. Even the manufacturer doesn't trust them past 500 hours. I don't think that bearings are a common failure at 500 hours, but that is their recommendation. Slick mags are very far from the most robust component on a lycoming engine. It is not the standard that I would follow when designing a part.

Larry
 
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Does slick use and interference fit on the shaft AND the bearing housing bore? My point was not the amount of interference, but that the bearing ID should be interference and the OD slip.

My intent was not to question your effort here, only to point out what I learned from engineers that do bearing application engineering for a living.
Larry

Hey Larry, No offense taken or implied. There are lots of people on here with a low more knowledge and practical experience then I have. That's why I asked.

In the Slick both inner and outer races are an interference fit, which seems to odd, given the need for internal clearances. That is why I asked what you and Dan had done

I agree mags are not the most reliable items on an aircraft, my point was that they have quite a few hours in the field.
 
Hey Larry, No offense taken or implied. There are lots of people on here with a low more knowledge and practical experience then I have. That's why I asked.

In the Slick both inner and outer races are an interference fit, which seems to odd, given the need for internal clearances. That is why I asked what you and Dan had done

I agree mags are not the most reliable items on an aircraft, my point was that they have quite a few hours in the field.

I suspect Slick had a reason for doing it. However, it goes against industry convention and I would exercise caution following their lead, unless you know why they did it.

FYI, mine has been in service for over 500 hours without a hiccup. The design is similar to the version dan posted. It will be interesting to see what Dan did on his bearings. I am sure his has as many or more hours on it.

Best of luck on the project. FYI, I built two of them and only used one. Happy to sell the extra if you get frustrated.

Larry
 
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I found a source for the EDIS pins. Just ordered 15 for $8 shipped. Let me know if you are in need.

If you buy a used module, get one with the connector, they are easy to un pin and reuse the connector body.
 
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I found a source for the EDIS pins. Just ordered 15 for $8 shipped. Let me know if you are in need.

If you buy a used module, get one with the connector, they are easy to un pin and reuse the connector body.

Hey Colin, that would be handy. We need enough to do at least 6-8 units over here.
 
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This project has taken longer than planned, had to go get cut-up by a surgeon and couldn't crawl under the panel for a while to finish the electrical. Weather permitting I am hoping for a first run this week.

If the collective mind her could give me a quick double-check on my assumptions I would appreciate it.

System is the EDIS + Magajolt, in place of the right side mag. Left side is the impulse mag.

1) Since I have a lightweight prop I have set the pickup to align with the 10th tooth after the missing tooth. This should retard the starting firing point by 10 degrees. As Dan reported if seems the EDIS will fire from +2 to +10 BTDC during start, so this should yield -8 to 0 degrees advance.

2) For first run I am programming the MJ map to 0 advance through 200rpm, then ramping to 15 at 400, then to a fixed 25 at 600. I have added 10 degrees to account for the pickup offset. I want the engine to be running at a fixed 25 degree advance so I can us the 25 degree marking to validate the timing with a timing light.

3) For the first start would it be best to start on just the impulse mag and then bring the EI on line? Do you think there is more/less risk starting vs running if the timing is way off?

Thanks,
Colin
 
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This project has taken longer than planned, had to go get cut-up by a surgeon and couldn't crawl under the panel for a while to finish the electrical. Weather permitting I am hoping for a first run this week.

If the collective mind her could give me a quick double-check on my assumptions I would appreciate it.

System is the EDIS + Magajolt, in place of the right side mag. Left side is the impulse mag.

1) Since I have a lightweight prop I have set the pickup to align with the 10th tooth after the missing tooth. This should retard the starting firing point by 10 degrees. As Dan reported if seems the EDIS will fire from +2 to +10 BTDC during start, so this should yield -8 to 0 degrees advance.

2) For first run I am programming the MJ map to 0 advance through 200rpm, then ramping to 25 at 400, then to a fixed 35 at 600. I have added 10 degrees to account for the pickup offset. I want the engine to be running at a fixed 25 degree advance so I can us the 25 degree marking to validate the timing with a timing light with no plugs.

3) For the first start would it be best to start on just the impulse mag and then bring the EI on line? Do you think there is more/less risk starting vs running if the timing is way off?

Thanks,
Colin

i put two EIs on an IO-540 rebuild recently. Didn't want to trust first start to luck/initial estimating, so pulled plugs and Mixture to ICO. Then cranked and observed timing. Skytech happilly spins the engine above my 250 cranking threshold.

Larry
 
1) Since I have a lightweight prop I have set the pickup to align with the 10th tooth after the missing tooth. This should retard the starting firing point by 10 degrees. As Dan reported if seems the EDIS will fire from +2 to +10 BTDC during start, so this should yield -8 to 0 degrees advance.

The manual states 5 to 10 degrees, which pretty much matches observation on a lathe.

2) For first run I am programming the MJ map to 0 advance through 200rpm, then ramping to 25 at 400, then to a fixed 35 at 600. I have added 10 degrees to account for the pickup offset.

See Global Controller Configuration Dialog. Nothing set in Megajolt software will have any effect below 200 RPM, when the Ford EDIS module apparently has full control. However, you can set the advance which will be active between 200 and 500 RPM. This is separate from the Big Map.

Point is, there is little value in specifying a mapped advance bin less than 1000. The software will extrapolate for all RPM between whatever is set in cranking advance and the advance value in the first mapped RPM bin.

Example: Clock 10 degrees as planned. Set "cranking advance" to 10. Header the first column on the big map as 1000. Set 35 in all spaces in every column.

Result will be cranking below 200 at 0 to -5, 0 (TDC) from 200 to 500, 600 = 5 BTDC, 700 = 10, 800 = 15, 900 = 20, and 1000 = 25. Everything above 1000 will be fixed 25 BTDC.

I use bins for 1000, 1500, 2000, then 100 RPM increments to 2700.
 
i put two EIs on an IO-540 rebuild recently. Didn't want to trust first start to luck/initial estimating, so pulled plugs and Mixture to ICO. Then cranked and observed timing. Skytech happilly spins the engine above my 250 cranking threshold.

Larry

Not a bad idea, that would tell me if I am in the ballpark.
 
The manual states 5 to 10 degrees, which pretty much matches observation on a lathe.



See Global Controller Configuration Dialog. Nothing set in Megajolt software will have any effect below 200 RPM, when the Ford EDIS module apparently has full control. However, you can set the advance which will be active between 200 and 500 RPM. This is separate from the Big Map.

Point is, there is little value in specifying a mapped advance bin less than 1000. The software will extrapolate for all RPM between whatever is set in cranking advance and the advance value in the first mapped RPM bin.

Example: Clock 10 degrees as planned. Set "cranking advance" to 10. Header the first column on the big map as 1000. Set 35 in all spaces in every column.

Result will be cranking below 200 at 0 to -5, 0 (TDC) from 200 to 500, 600 = 5 BTDC, 700 = 10, 800 = 15, 900 = 20, and 1000 = 25. Everything above 1000 will be fixed 25 BTDC.

I use bins for 1000, 1500, 2000, then 100 RPM increments to 2700.


Dan,

Thank you for the help. I set up the MJ as noted above. I started the engine on the left mag and the brought the EI online. The timing was a good 10 degrees off (per the timing light), so I adjusted to match the 25 degree mark on the rear of the flywheel.

I must have a problem with my installation, i am getting a slight ping when the EI on, and poor running with afterfire (i think) when running only on the EI. I belive I may have my cylinders paired incorrectly. Or have a cylinder dropping in and out.

I need to confirm I have my ignition harness going to the correct coil posts.
 
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Ok, using the Pmag manual for reference (same coil), looks like I swapped 2 and 4, that explains a lot.
 
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Bearing Fit

I suspect Slick had a reason for doing it. However, it goes against industry convention and I would exercise caution following their lead, unless you know why they did it.

FYI, mine has been in service for over 500 hours without a hiccup. The design is similar to the version dan posted. It will be interesting to see what Dan did on his bearings. I am sure his has as many or more hours on it.

Best of luck on the project. FYI, I built two of them and only used one. Happy to sell the extra if you get frustrated.

Larry

Interference fit of both the inner and outer races is really the only way to ensure that engine oil from the accessory case can't seep around the sealed bearing without introducing another seal into the assembly.

Skylor
 
Dan,

Thank you for the help. I set up the MJ as noted above. I started the engine on the left mag and the brought the EI online. The timing was a good 10 degrees off (per the timing light), so I adjusted to match the 26 degree mark on the rear of the flywheel.

I must have a problem with my installation, i am getting a slight ping when the EI on, and poor running with afterfire (i think) when running only on the EI. I belive I may have my cylinders paired incorrectly. Or have a cylinder dropping in and out.

I need to confirm I have my ignition harness going to the correct coil posts.

I made that mistake (mismatched coil connection) and got the same afterfires. You put two pieces of tape on the flywheel; One at TDC and the other 180 opposite. Mark them 1 and 2. Put the timing light on #1 top plug and spin the engine with bottom plugs out and ICO. #1 tape (or whatever you marked for the TDC position) should be in the light. Move light connector to #3 plug and spin again. The other numbered tape should be in light.

You need to be carefull with wasted spark, as both plugs on the coil fire at the same time. If I remember the 4 cyl correctly (I recall FO:1324, but can't be sure), coil pairs are 1/2 and 3/4. You can have similar problems if not paired correctly. When a coil fires, one plug should be in a cylinder that is in compression and the other plug should be on a cyl that is in exh stroke. On a 4 banger it is easy. With the crank set at TDC via the flywheel markings, the two cyl at TDC are on the #1 coil and the two at BDC are on the #2 coil.

Your EI should reference which coil connection is intended for the first plug to fire in the rotation. I would expect it to be labelled Coil 1 or Coil A, as Megasquirt calls it. Vaguely remember this being an outgrowth of the MS code base.

Larry
 
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Interference fit of both the inner and outer races is really the only way to ensure that engine oil from the accessory case can't seep around the sealed bearing without introducing another seal into the assembly.

Skylor

The slick mag already has an oil seal on the shaft at it's base that separates the bearing from the accy case. I don't believe any design engineer would trust a bearing with an interference fit to prevent oil migration without an oil seal, especially in a splash environment like the accy case.

It's more likely that their reason was shaft retention. I can't remember if their is a bearing retainer, but guess there is not and they use interfererence fits to hold the shaft in place.
 
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The slick mag already has an oil seal on the shaft at it's base that separates the bearing from the accy case. I don't believe any design engineer would trust a bearing with an interference fit to prevent oil migration without an oil seal, especially in a splash environment like the accy case.

It's more likely that their reason was shaft retention. I can't remember if their is a bearing retainer, but guess there is not and they use interfererence fits to hold the shaft in place.

Ther is no bearing retainer, but you’re correct about the oil seal. The double interference is likely for shaft retention and to ensure the bearing races don’t spin free within their bores or on the rotor shaft.

Skylor
 
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I made that mistake (mismatched coil connection) and got the same afterfires. You put two pieces of tape on the flywheel; One at TDC and the other 180 opposite. Mark them 1 and 2. Put the timing light on #1 top plug and spin the engine with bottom plugs out and ICO. #1 tape (or whatever you marked for the TDC position) should be in the light. Move light connector to #3 plug and spin again. The other numbered tape should be in light.

You need to be carefull with wasted spark, as both plugs on the coil fire at the same time. If I remember the 4 cyl correctly (I recall FO:1324, but can't be sure), coil pairs are 1/2 and 3/4. You can have similar problems if not paired correctly. When a coil fires, one plug should be in a cylinder that is in compression and the other plug should be on a cyl that is in exh stroke. On a 4 banger it is easy. With the crank set at TDC via the flywheel markings, the two cyl at TDC are on the #1 coil and the two at BDC are on the #2 coil.

Your EI should reference which coil connection is intended for the first plug to fire in the rotation. I would expect it to be labelled Coil 1 or Coil A, as Megasquirt calls it. Vaguely remember this being an outgrowth of the MS code base.

Larry

Looks like i have 1&3 correct, I just had my paring wrong. If I swap 2&4 I should be good
 
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Ther is no bearing retainer, but you’re correct about the oil seal. The double interference is likely for shaft retention and to ensure the bearing races don’t spin free within their bores or on the rotor shaft.

Skylor

A bearing doesn't need to be held, via interference fit or otherwise, in order to not spin. Radial intertial forces keep the the inner or outer surfaces from slipping. In a properly working bearing, there is much less friction in the in race / ball interface than the retaining surface interfaces, so this interface breaks the inertial force first with the mounting surfaces still held by inertial force. That said most bearing companies recommend a few PSI of axial tension on the assembly to insure tiis. It is very standard for only the internal or external fit to be interference and not both. This improves bearing life.

Larry
 
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Best to use a good reference for any design incorporating bearings. A glance at the SKF catalog says they needed 24 pages, with tables, to properly specify radial bearing fit. I'm just sayin'...
 
Just to follow up, after I swapped the 2&4 positions on the coil, everything is working great. I have to do more ground testing, but eventually it will be ready for flight testing. I set up two maps, one with a flat 25 degree advance to match the mag. The second has an advance curve similar to the recommendations from SDS. Once I am flying I can start to play with the curve and performance.

I did most of the wiring for a second system while I was installing the first. The plan is to eventually have a dual EI setup with a dedicated backup battery.
 
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.

Early%20Coil.jpg


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

Late%20Coil.jpg


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.
 
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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.
 
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.
 
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VR pick up

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.

Wheel.JPG


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:

Kirks%20Wheel.jpg


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.

Waveform.jpg
[/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?
 
New OEM Ford parts, common as dirt. Or any wrecking yard for pre-loved.

Or, https://www.autosportlabs.com/product-category/megajolt-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.
 
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.
 
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 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
 
Anybody have a Megajolt they are not going to use?

I need a Megajolt for a project this winter and before I buy a new one, thought I would check here to see if there were any abandoned ignition projects out there.

If you have one you are willing to part with - PM me and let's talk.

Thanks!
 
Pete, remember, there are versions. The /E Mk2 programs via USB rather than serial, plus it has a rev limiter and better power supply protection.
 
Thanks Dan!

Good features to have. I should retire my airplane only db9 serial laptop at some point........

Pete, remember, there are versions. The /E Mk2 programs via USB rather than serial, plus it has a rev limiter and better power supply protection.
 
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