Eureka?

I may have gotten it done! Needs to be nailed down, so to speak, and then it needs tested in an EEC-IV system somehow. I think spinning it in a drillpress and hooking an elec meter will suffice. Will need to figure out where all the #1s align (between 5.0 and Mopar) before I tackweld the trigger wheel. Need to do this in a bigblock housing after that.

There is not a lot of clearance for all this, so you’ll need your skills, and there are some subtle details involved too. Unless you have a handful of Ford and Mopar dizzys to sacrifice, read the info below while doing it and think 2-3 steps ahead -- because I am typing what I remember, a full 5 days after doing it.

I highly recommend using a remote-mount TFI distributor for this retrofit. Ford’s TFI was notorious for having heat-related issues with the TFI module (it’s the gray plastic thing that mounts to the side of a Ford dizzy and hooks into the brown part in the pics below). Module gets hot, ignition dies, then car starts up when it cools off – pretty easy to diagnose when you know what to look for, but let’s try to avoid it instead. The module requires heat-sink compound between it and the dizzy housing, and if omitted the TFI can overheat. Ford started remote-mounting the TFI on T-birds, trucks and some others around the early 90s, and the brown component is moved into the remote-mount setup also, so wires are all that must exit our dizzy in that case. More info: http://www.therangerstation.com/tech_library/remote_tfi.htm

Some of the tips to success:
To re-cap, the Ford wheel is a larger diameter than the Mopar wheel, and the Ford dizzy is larger diameter also. Grind some of the sensor so that it can be shoved closer to the dizzy housing. Grind some of its mounting pins off also, then drill them for mounting screws. Feed the sensor’s connector thru the slot on the side of the dizzy. (I don’t fully know where this housing came from, the slot is for a vacuum pot, perhaps TBI and Mag dizzies may not have this slot?)

I am undecided on whether the shaft collar should be cross-pinned to the dizzy shaft. It will grip the shaft pretty well and I doubt it would ever creep out of alignment due to the low mass of the trigger wheel, but things would get ugly with the fuel timing if it ever did. I don’t know if it could cause engine damage - the ignition timing is controlled by the EEC based on the wheel, but it can only deliver to the sparkplugs based on the rotor, which is fixed to the shaft by a tab, so I don’t think it can deliver spark to the wrong cylinder at a wrong-enough time to cause damage. Regardless, it would be a PITA to diagnose if it started to creep.

Grind some of the sensor ‘reflector’ down to get it to fit better. Grind pins / drill mounting holes.


I held the sensor in place based on the wheel location so that gaps between the wheel and sensor would be correct, then drilled one mounting hole. Snugged that screw in place, the re-aligned and drilled the 2nd hole. Held the wheel to the shaft collar and rotated the housing. Felt some rubbing, so I wallowed one of the holes slightly, re-adjusted the sensor, and it was perfect.


Here the shaft is pushed up as normal so that you can see under the shaft collar. The shaft collar must be high enough for the bottom of the wheel to clear the sensor, but low enough that the dizzycap rotor can bottom out on the shaft (remember that we still have to preserve the rotor/cap geometry!). Do not sink the wheel so low that it can read the top part of the wheel, which does not have window breaks in it. Note that the sensor is not centered, this is one of the tricks to making the Ford sensor fit.


A little grinding to get the serrated-flange locknut to fit.


Trigger wheel is just a little above the housing base. Encyclopedia Brown-types will notice that the wheel in these pics is gold-colored, unlike the prior Ford wheel I pictured, which is a dark color. This particular wheel was from a V-6 Ford, and was sacrificed for this latest experiment. The correct wheel still needs to be tack-welded to the shaft collar.