3.9 Odd fire vs Even Fire

At one time mopar performance made a reluctor to run a regular ignition in a 3.9. That part is loooong since discontinued.

I modified a distributor cap and a v8 points distributor to get the engine running. The timing events are off on a couple of cylinders. It runs, but I am no happy with it. So, I have a 3.9 that runs, but not the way it should. It is an 87, so it has a mechanical fuel pump, carb and etc.

Anyone know how to modify a V8 or /6 reluctor to work for the 3.9, I think modifying the points cam is probably not as feasible.

Thanks,

sb

Haven't done so, but perhaps you could add a Pertronix Ignitor for the slant-six to your V-8 points distributor. The Ignitor has its own "reluctor" and the distributor shafts might be the same between slant and small-block or close enough to adapt w/ a bushing. One reason I suspect this might work is that I have had Crane Cams XR700 kits that I recall came w/ optical wheels for 6 or 8 cyl, which suggest the distributor plate pickup mounts are the same. You can't get there w/ the XR700 because the plastic optical wheel fits over the rotor cam, so a 6 cyl won't fit a V-8 cam.

What many do for Magnum swaps is use the flex-plate pickup. When used w/ an older 904 tranny, you just cut a slot in the bell-housing top and use the Magnum pickup w/ holder that comes off 2 bolts (search posts w/ photos). Of course, then you must use the Magnum PCM for spark, but that is easy if also using MPFI (I would).

Another approach is to fit a Ford EDIS ignition. That requires a 36-1 trigger wheel on the crank and VR pickup. I put one on my 273 engine (post w/ photos) so "should work", dep on your pulleys. I haven't run it yet. But that requires a spark controller (Megasquirt, etc).

You're going to have to replicate the diso'd reluctor, or else you're going to have one of two things, a shitty running 3.9 or a blown up 3.9. Even fire isn't an option there, and I
see no way to make any existing reluctor into what You need. Same for points. Sorry. Why do You want to do this, if I may inquire?

Killer6 said:

You're going to have to replicate the diso'd reluctor, or else you're going to have one of two things, a shitty running 3.9 or a blown up 3.9. Even fire isn't an option there, and I
see no way to make any existing reluctor into what You need. Same for points. Sorry. Why do You want to do this, if I may inquire?

Click to expand...

I have the extra engine sitting around and an 87 Dakota with the same engine that I'd like to "retro" to make tuning possible. As it is, it runs but the analog computer on the fender is meh, at best.

If I had a picture/drawing of the old MP reluctor I could maybe make something.

sb