Dr_Snooz's EDIS Conversion Thread

[Dr_Snooz]

We all know that the 3g distributors are tired. Junkyard units are hard to find and usually too far gone to save. Some replacement parts are available, but they tend not to work. "New" distributors are on sale at RockAuto.com, but I went through 3 of them, all junk, before giving up. These distributors are done.

This makes the EDIS conversion look pretty good.


Background

The EDIS, or Electronic Distributorless Ignition System, came on a lot of Ford cars during the '80s and '90s. It is a simple, robust and inexpensive improvement over mechanical distributors. It came in 4, 6 and 8 cylinder flavors and has become popular with classic car enthusiasts because it does not require a camshaft position sensor. Instead, it uses a crankshaft position sensor and the "waste-spark" principle. It knows that when cylinder 1 is at TDC, cylinder 3 is also at TDC. One cylinder is on its compression stroke, the other on its exhaust stroke. EDIS doesn't need to know which is which. Instead, it fires both plugs simultaneously. One spark ignites fuel, the other spark is "wasted" on the exhaust stroke. Simple, right?


The Parts

Donor vehicles for our 3g's would be Ford Escorts between the years 1988 & 1993 with the 1.9L engine. You can find the EDIS system on cars ranging up to the 2001 Ranger, but in the years following 1993, Ford incorporated the ICM into the ECU, so you can't pull it off and use it on your car. While we can use some of the parts off these newer cars, they don't make good donor cars. I will be using the following parts to make this system work:

1. Megajolt E/MK2 spark controller (not pictured)
2. EDIS trigger wheel - I just bought the crank pulley for a '93 Escort
3. Ignition coil - again for a '93 Escort
4. Crank sensor - '93 Escort again
5. Plug wires - I'm not yet sure how these will fit, lengthwise
6. Ignition Control Module (with the Ford connector) - this is an expensive piece to buy new and worth the trip to the junkyard to obtain
7. Ford connectors for the crank sensor and coil
8. Whatever wire you need to wire it all up
9. PS pulley from a 4g Accord (because I hope to keep my power steering)

In every case but the ICM, the junkyard thought their scrap parts were worth more than new parts, so I bought them new. It's a lot easier than spending an afternoon getting dirty. Get the connectors and ICM from the junkyard and let them keep what they think is so valuable.


The Plan

For the most part, the conversion will be pretty easy. Find a place to mount all the components, wire them together, spend some time on your laptop and go. The tricky part for us is mounting the trigger wheel and crank sensor on the crank pulley. On the 3g, there isn't anything to mount to down there and not much room to work. My car has both AC and power steering, neither of which I'm willing to give up. I have to make it work somehow.

Problem #1 - Mounting the toothed trigger wheel

Fortunately, the trigger wheel on the '93 Escort crank pulley pops off. Thus, I only need to find a machine shop willing to weld it onto my existing crank pulley. Because there is so little space in the bay, the only place I can put the trigger wheel is over top of the PS pump pulley. Either I have to give up PS (not an option) or move the PS pump to be driven off a different pulley.

Problem #2 - Moving the PS pump

Here is the 3g crank pulley. It has 3 pulleys: One for the alternator and water pump. One for the AC compressor, and one for the PS pump.



Here is my PS pump and bracket.



You can see that there's a lot of material on the pump bracket pushing the pump way far out to align with the outermost pulley on the crank pulley. My plan is to shave it down so the pump can be driven off the AC pulley. The AC pulley is a 4-groove serpentine-belt. My PS pump is a V-belt. Thus why I got the 4-groove serpentine pulley off a 4g Accord. I have no idea how to mount it, but I have to figure it out. Worse, with the current small crank pulley driving the PS pump, it is slightly underdriven. If I move it to the AC pulley, it will be over-driven by quite a bit. I'm not sure how that's going to work out, so I might end up casting about for a larger PS pump pulley before this is over. The other problem is that by including the PS pump on the AC belt, there might not enough contact surface on the driven pulleys to keep the belt from slipping. I might have to over-tension the belts to the point that I get premature bearing failure in the driven components. We'll see.

Problem #3 - Mounting the crank sensor

This might be the least of my problems. The AC bracket is mammoth and provides a really substantial mounting surface in reasonable proximity to the crank pulley. It will require some creativity, but will probably work well when I'm done.


Disclaimer

I have about 175 things on my project list and they are constantly re-prioritizing themselves as crises arise. Be patient and don't expect frequent updates here.

This is a work in progress and I have no idea how it will turn out. It might be very successful, or it might be a disaster. If it's successful, then you can use it for your car. If it's a disaster, you'll have a good laugh. Either way, you win.

Wish me well.

[conozo]

Good luck.

Thinking out of the box here: Is it possible to mount the trigger wheel on the camshaft sproket or file down a few mm off an edge of one tooth on the cam sproket then mount the sensor under the cam gear in the timing cover.

I know many guys have mounted a trigger wheel on their crank pulley but i am pretty sure they dont have AC or PS.

[ShiRen]

I would think twice about the escort trigger wheel, that thing is chunky, plus a bolt on part has its advantages. 32-1 trigger wheels are easy to come by. Honestly if you want my protege one Ill send it to you for half of what a new one costs. Ill just quote my other comment about pulleys.

Mazda Protege crank triggers or Megasquirt are good crank trigger options.

Also, for the crank trigger, this is the megajolts life line and it suggests you use shielded cable. You can simply splice this cable in as close as you can to the original wires on the connectors and then ground the shield.

You should also run a shielded cable for the hall effect sensor. I found this a while back

As for the crank trigger bracket, I think the AC could be unbolted, a plate added behind it, and then bolted back on over top.

As for the power steering, easiest solution, and the increasingly more popular solution is an electric pump.

It would be really nice to have a crank pulley like a miata, it looks like this:

And bolts to the crank like this: