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Ford Electronic Distributorless Ignition in Willys Jeep Tornado Engine - why & how to do it.

Why do it:

Even if you 'tune' the factory ignition system almost perfectly, it will lose adjustment to the detriment of accurate sparking. It is said that points can be slightly burnt if the ignition is left on with the engine not running, but in any case they do deteriorate quite quickly. Further, it is not possible to set the factory system to adapt to engine temperature or altitude.

With increasingly demanding Aircare requirements it makes sense to update the old 'points & condenser' based ignition system.

There are many different 'electronic' ignitions systems available for older engines - some fit conveniently under the old distributor cap like the Pertronix systems. Other possibilities include adapting a Chevy HEI distributor to the Willys engine. The problem, of course, is that you still have a distributor with its mechanical drawbacks.

Ford made a huge step forward in the early 1990s with their Electronic Distributorless Ignition System (EDIS). Brent Picasso's MegaJolt Lite Junior system allows control and programming of the Ford ECU, so that almost any engine can benefit from the Ford EDIS. Advantages are:

  1. elimination of distributor altogether - no points/condensor/mechanical centrifugal advance
  2. sensing is directly from crankshaft - no sloppy gearing
  3. super proven Ford technology
  4. used parts available in almost any large wrecking yard (cheap)
  5. stronger spark - spark gap can be increased to 40 thous (1.16mm) or more
  6. MegaJolt controller is completely programmable (2 different programs can be loaded)
  7. Ignition advance inputs can be made for engine temperature as well as the engine speed and vacuum/load
  8. Outputs for tach, rev limiter and shift lights
  9. Limp Home mode. Should the Mega Jolt controller fail or just be disconnected, the Ford EDIS reverts to a set 10 degrees before top dead center setting to keep the engine running.
  10. Since the Ford EDIS is a so-called "wasted spark" system where the spark plugs fire every crank rotation, any unburnt fuel should be ignited near the end of the exhaust stroke. This has the added benefit of decreasing hydrocarbon readings in emissions.

How to do it - 6 components and then computer setup:

Required for the change to EDIS in a Willys are the following components that can be found in wrecking yards - I got them from Boost Engineering:

  • Ford EDIS module (+ custom homemade bracket)
  • Coilpack (+ custom homemade bracket)
  • Crank position sensor (+ custom homemade bracket)
  • 36-1 Trigger wheel (attach to crank pulley/harmonic balancer)
  • MegaJolt Lite Junior controller from Autosport Labs (+ custom homemade bracket)
  • Fused circuitry using Ford connectors and aftermarket relays
  • Access to correct Laptop computer with old fashioned 'Serial Port'

Step 1: Making Your Own Custom Trigger Wheel aka "Steel Plate Origami"

It would be wise for anyone needing a so-called 36-1 trigger wheel to buy one from the many suppliers out there. Most wheels cost only about $20-30 but some from overseas cost as much as $55-75 delivered. These wheels are about 1/4" thick and either laser or water cut to be quite accurate. You can also get a pressed sheet metal trigger wheel from Ford Parts UK for £12.80. Ford Granada disc Assy c/Shaft And Ign Timing Part number 1078767.

Being a person who will always take the high road which ends up being the most difficult, I decided that I wanted a lighter trigger wheel, one that was exactly 6-1/2" diameter. No large enough wheels, ready made, seemed to available in the States - there was one source in England. Having been burned on overseas delivery with large unexpected costs due to customs brokers, taxes, etc., I decided to make my own wheel. How difficult could it be? The answer to that rhetorial question, of course, is bloody difficult and time consuming!

In the end, the homemade trigger wheel was the best for my application and all the heartache was forgotten. So, here is how I did it. The idea of making my own wheel came from the work of Matthew Kimmins in the UK.

Trigger Wheel Template and 12 gauge steel

A template for the trigger wheel can be downloaded from

KEW Engineering Trigger Wheel Template

I took the template to the local photocopy shop and increased the size by 48% so that the outer ring, at the base of each tooth would be 6 - 1/2 inches in diameter. I used #12 Lepage 5 minute epoxy glue to carefully attach the paper template to the cleaned metal. It is important that the template survive abuse and still remain attached to the work until the end.

12 gauge domestic cold rolled steel was bought for $10 and rough cut into a circle with a jigsaw. 14 gauge would have probably been thick and strong enough but I wanted to be sure that the teeth wouldn't bend due to centrifugal force. 12 gauge is about 2.5mm thick while the source website recommended any gauge that had a thickness between 1 and 2mm. The extra 1/2mm might come in useful if the teeth needed to be ground down...

Tooth Rough Cut

Instead of using a grinder with cut-off wheel to make the initial tooth rough cuts, I used a good old hacksaw. 72 cuts take over 1 hour. I cut slightly too deep on about 3 or 4 cuts... bad!

Teeth roughed out

Here you can see the trigger wheel with the inter-tooth areas broken off with pliers and with the first attempt at careful tooth dressing using a cut off wheel on my angle grinder. The width of the teeth is supposed to be the same or less than the gaps between the teeth - I'm not there yet.

If you look carefully at 9 o'clock just below the base of the teeth, you can see that I used a compass to redraw the circles on the template. The photocopy enlargement process is not accurate at all. The photocopied circles ended up being ovals.

Wheel Centre Hole Cut Out

After considerable tooth dressing with grinder and file, I rough cut out the middle hole with a jigsaw and then rounded the inner contour with an arc profile file to follow my redrawn center hole.

I center-punched 36 positions for future alignment holes yet to be drilled. Without proper machining equipment (dividing head) it is not possible to accurately punch the hole positions. This can be dealt with later however.

The pointer indicates the place where I first thought an extra hole must be cut to balance the missing tooth at the top. We are a long way from that job!

Alignment Holes for Wheel

The 36-1 wheel was first centered and clamped on the harmonic balancer/pulley unit. It is critical to have the best alignment possible "by eye".

Then three 1/8" alignment holes were drilled for temporary attachment of the trigger wheel. I will change the relative clocking of the wheel later, but the three holes allowed me to work on the teeth more.

Teeth Bent with Pliers

With the rough trigger wheel now attached using 3 temporary sheet metal screws, I bent each tooth about 20 degrees using parallel jaw pliers. Do not use strong gripping visegrips as these will leave deep scoring on both sides of the teeth.

Teeth Persuaded with Hammer

Now, very carefully 'persuade' the teeth over the outer edge of the harmonic balancer using a ballpeen hammer. Easy does it! I ended up going round the 35 teeth about 5 times, bending a little more each time. No crooked teeth please!

Tooth Length Dressed

The next step involved flipping the rough trigger wheel over and reattaching it to the harmonic balancer. Amazingly, my alignment holes line up accurately - lucky?

Now to dress the teeth to the same length (slightly too long). In a moment of inspiration, I devised a flat surface on the work bench shimmed to the correct height so that my vise gripped grinder could cut horizontally.

Once again, by cutting slightly each rotation, I was able to remove a little material each time. 5 or 6 times around and all the teeth were almost uniform in length.

Trigger Wheel Trial Fitment

First trial fittment of the trigger wheel in place on the pulley/balancer on the crank. You can see the teeth are just touching the timing mark on the front engine cover. I must take a little more off each tooth and then align the trigger wheel to the crank position sensor.

This was a good time to start thinking about where to locate the crank position sensor.

Further Tooth Dressing

Here, I am removing a little bit off the teeth the good old fashioned way. This has to be done several times. I suspect that when the pulley/harmonic balancer with trigger wheel is bolted and torqued onto the crank, the teeth might still be a bit too long...

Trigger Wheel Template Still There

I left the template on the wheel until the very end of fabrication. Here you can see the missing tooth at 6 o'clock and the balancing triple hole at 12 o'clock. The area of the missing tooth was 0.1054 square inches, which is about equivalent to 3 holes of 13/64 inch diameter.

Trigger Wheel To Paint

Here is the wheel ready for paint. I noticed that the teeth were the same width or slightly wider than the gaps. Another 60 minutes of grinding and filing produced teeth that were uniformly narrower than the gaps. This, of course, introduced an error in the balancing... the three holes should have been slightly smaller, perhaps 3/16". Hmmm.

From Whence We Came I have plenty of 12 gauge material left for at least 2 more homemade trigger wheels...
Trigger Wheel Ready To Attach

At last, here is my home made trigger wheel painted and attached with 6 SS fine thread 1/4" bolts, 3/4" long; SS lock washers and blue (#242) Loctite in place. Torqued to 7 ftlbs. Smaller bolts might well have been sufficient and would have been lighter.

Word of warning: it is possible that the outer pulley may have slipped/twisted slightly on the inner part of the harmonic balancer. The two parts are only held together by a compressed rubber band. Check that your assembly still reads zero degrees (TopDeadCenter) when the No. 1 piston is at the top of its movement. Ours was still fine after 45 years of use.

To set the trigger wheel properly:

  1. turn the engine to exact top dead center. To check that piston #1 was at top dead center, I removed the spark plug, inserted a coat hanger wire and turned the crank back and forth to observe the wire's movement...
  2. turn the trigger wheel so that the missing tooth faces the sensor (no matter where you position the sensor). Mark this position on the harmonic balancer very carefully and then remove the balancer and trigger wheel.
  3. with the balancer and wheel on your bench, align your wheel to the exact spot you marked and then.... turn the wheel 'n' teeth (for a 6 cylinder engine, 'n' = 6 teeth) clockwise from that point and fix the wheel to the pulley. By clockwise, I mean looking at the harmonic balancer/pulley from the front.
  4. This is for a clockwise turning (from the front looking backwards) engine. The simplest way to determine if you engine is a clockwise or counter-clockwise unit is to check the fan. By imagining the fan in position, turning, you can figure out is your engine is a CW or CCW unit. The turning fan should draw air through the radiator.
Signal Calibration

Step 2 Sensor position optimization

The triggerwheel/harmonic balancer can be seen here mounted in an old non-running lathe (that I picked up for $50). The sensor is clamped to the tool post and aligned closely perpendicular to the teeth. Next my old analog multimeter, set for 2.5 milliamp scale, is connected to the leads. and all that was necessary was to turn the wheel by hand.

0.3 mm gap

Another angle shows the simple set up

CPS alignment

Now to determine the position along the teeth that would give the strongest pulse. The lathe carriage movement along the bed allows easy adjustment.

The yellow markings on the harmonic balancer are the old timing marks. I made absolutely sure that the zero mark, which indicates Top Dead Center was accurate. Once the trigger wheel is correctly attached, you will never need to time the engine with a timing gun ever again!


Here you can see the black Ford sensor with its center line on the plastic housing. With the center line aligned at 2.5mm to the left of the tip of the tooth - as shown here - I got the strongest signal - a consistent 0.33 to 0.37 milliamps from the sensor. That should do the trick.

So, now, all that is necessary is to mount the harmonic balancer/trigger wheel and CPS back on the engine. The CPS must be mounted no more than 0.3mm distance away from the teeth and with centerline at 2.5mm down from the tooth tips.

Crank Sensor Bracket Design

Step 3 Crank Position Sensor attachment

The CPS must line up accurately and within 0.3mm of the trigger wheel. The bracket that holds the sensor must be strong and not subject to vibration. I located 2 bolts that hold on the front aluminum engine cover and decided to add the sensor there.

In order that the sensor can be adjusted inwards and outwards, I used stacks of plain washers. The aluminum plate shown had to be held proud of the engine front cover for two reasons: firstly the engine cover had an irregular shape which would not allow the bracket to sit flat, and secondly, there needed to be room for the sensor small bolts to have a 'captive nut' system under the plate. I simply (and crudely) welded two nuts onto a small plate. The holes in the aluminum bracket are deliberately too large where the sensor bolts go through... this allows CPS position adjustment.

Front Cover Holes

Here are the attachment points on the front engine cover that are closest to the position needed for the CPS. The unfinished trigger wheel can be seen at the bottom of the picture.

Crank Bolt Lock

The final CPS set up with SS fasteners which will avoid any possible interferance with the clean magnetic field pulses - no doubt overkill. Note where the shielded cable plugs into the sensor. The 22 gauge microphone shielded cable then goes to the Ford EDIS module on the fenderwell.

The exact position of the sensor must be determined back in Step 2 above, so that the strongest pulse will be generated... This was determined with the CPS system off the engine.

Due to the tight fit with the front crossmember, it is not possible to remove the harmonic balancer/pulley/trigger wheel unless you undo the engine mounts and lift the engine.

When I removed the pulley/harmonic balancer the big securing bolt was completely loose and only held in place by the crank bolt locking plate and its two bolts - quite a discovery.

Final Sensor Setup

Here is another view of the final trigger wheel and sensor setup showing the stacks of washers used as spacers.

The yellow captive nut plate (no wrench needed back there) behind the aluminum deck is a time saver - adjustment of crank position sensor simply involves loosening the two small metric bolts.

The sensor and its wire must not interfere with any belts on the front of the engine.

Harmonic Antiturn Tool

Crank bolt torquing.

Here is my homemade tool to hold the crank from rotating while the big 1-1/8" crank bolt is tightened to 120 ft/lbs. I simply welded some scrap metal flanges (with holes) to a piece of bed frame. My homemade tool attaches to the crankbolt locking system making the tightening job straightforward... simply hold the bedframe lever with one hand and torque with the other.

Time for a pint...

Board Construction

Step 4 MegaJolt V4 controller assembly

This is the end of the first part of assembly - the power supply. The circuit test uses a temporary 9 volt battery hook up. This was our first attempt at "surface mount" circuit board construction - not too difficult with a good quality soldering system and small tip.

MJLJ Internals Here is the V4 MegaJolt Lite Junior circuit board fully assembled with the phone jack computer hookup at the top left, the connection to the Ford EDIS module (plus power and ground) at the right. I am holding the vacuum line from the manifold that will allow engine load to be measured. Very tidy.


The completed MegaJolt controller was attached under the Willys dashboard and wired with minimum connections. On the right are the fused 12 V power (12 gauge red), ground (12 ga black) and the two 22 ga communications with the Ford EDIS computer (SAW red and PIP white). The copper wire is the twisted shielding over the signal wires which connects only at the EDIS end.

On the left, the grey 'phone cable link connects the MJLJ to a laptop for programing.

It might be wise to change the attachment of the MJLJ Controller from bolts to a foam cage so that less Willys suspension vibration gets through to the MJLJ unit...

Ford Coil Pack

Step 5 Locating Coilpack & Ford computer

In these two pictures, you can see the brackets I made to hold the coilpack and the Ford EDIS6 computer. The coilpack brackets attach to the engine front cover and the EDIS module sits on the passenger fender well.

Considerations for mounting the coilpack and Ford EDIS computer:

  • efficient routing of spark plug wires
  • 1-5-3-6-2-4 firing order (which is different from a Ford V6)
  • heat from the exhaust system
  • vibration (there needs to be plenty of slack in the wiring)
  • special spark plug wires are needed with different coilpack connections
  • All the main components (used) came from Boost Engineering including spark plug wires. <www.boostengineering.net/caregory_s/3.htm>
  • Boost includes a Ford trigger wheel and a safety fuel cutoff switch neither of which was useful in our Willys.
  • Boost guarantees the components function properly.
Ford EDIS ignition in place

Step 6 Wiring

It is wise to solder all wiring splices. I used crimp splicers, then soldered them and then covered with shrink wrap tubing. Not yet bound with electrical tape and plastic protector, there is still time to make changes.

Considerations for mounting the coilpack and Ford EDIS computer:

  • heat from the engine
  • vibration (there needs to be plenty of slack in the wiring)
  • firing order
  • special spark plug wires are needed with different coilpack connections (I got a used 8mm set from Boost Engineering)

A is where the homemade trigger wheel sits on the inside of the harmonic balancer

B is the Ford EDIS computer sitting on a homemade bracket attached to the passenger fender

C is the Ford Coil Pack supported by more homemade bracketry. It would be more pleasing to have the coilpack mounted where the no-longer-to-be-used distributor is but I can't get the distributor out!

D is the shielded 22 gauge cable from the Crank Position Sensor to the Ford EDIS unit. I used copper shielded microphone wire but some installers believe this type of non-automotive wire will have a limited lifespan.

E is the 5/32" vacuum hose that connects the Megajolt MAP sensor to the manifold. Since the old distributor vacuum supply tube did not come from the carburator (not "Ported Vacuum") and was nearby, this was an easy hook up. If the vacuum supply had come from the throttle plate area - "ported vacuum" supply, then it would have been useless for the MegaJolt application.

F is the old distributor cap, still in place. The OEM distributor has defied all attempts at loosening. I have tried chemicals along with twisting, hammering, vibration, heat, cooling with dry ice - no luck so far.


Willys EDIS wiring diagramme The Ford EDIS/ MegaJolt system requires fused circuits and relays in my opinion. Of course, many people do not bother with these complications. I installed a 6 fuse panel under the dashboard - the panel is powered from a specific terminal on the ignition switch. This terminal is powered when the key is turned 'On' and also when the key is turned to the 'Start' position as shown at left. Main feeds for the 2 relays come from the battery with inline 5 and 15 amp fuses. It seems to work well but I only guessed at the fuse values and should look at the OEM fuses in a Ford to find out how far off my guesses are...
Megajolt Default Map

Step 7 Programming the MegaJolt Controller

The MegaJolt Lite Junior controller comes with an average set of ignition advance values already programmed. Of course, a set of values best for the Tornado engine have to be determined...

Global (Basic) Values.

First, the amount of error in positioning of the 36-1 trigger wheel on the crankshaft harmonic balancer must be determined. With the MegaJolt Controller disconnected, a Timing Light on the front pulley should show 10 degrees BTDC (the Ford ECU default setting). Our case gave 11-1/2 degrees, so we were about 2 degrees out.... not bad.

Second, the amount of advance at Start was set to zero to mimic the factory setting. This advance works up to 500 rpm, then the advance jumps to the MegaJolt setting for 1000 rpm.

Ignition Map Values.

MegaJolt comes preset with the ignition values shown at left. Of course values above 5500 rpm are not needed for the "Bronze Age" Tornado engine! To program a specific Ignition Map for the Tornado engine, one of the following can be used:

• Factory OEM values for advance (full Map for most RPMs, vacuum values is not available for our engine)

• Use a previously developed map available on the MegaJolt Library website (none were available for our engine)

• Take the vehicle to a "Rolling Road" dyno-clinic and have professionals develop the optimum map (best but no doubt expensive)

• Develop a custom map for your specific engine yourself (very time consuming - how the hell do you actually do it? I have much to learn!)

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Warning: any change to the factory design of your vehicle has potential dangers which could result in injury or death. Make sure any design changes or repairs are performed by competent, experienced technicians. This page last updated: Sunday,
July 11, 2010