Electronic distributors and tuning them.

[Kern Dog]

In 2001, I built a 440 for my Charger and did my first big block swap. The car had a 318 so this was a big step for me.
I’d already read the tech articles in the Mopar magazines and wanted electronic ignition. I installed a complete kit from Summit Racing…Mopar Performance distributor, orange box ECM/ECU, ballast resistor and the wire plug for the spark box. Installation was easy. The car ran great but had a habit of sometimes suddenly misfiring. The reluctor air gap would go from the .008 to as much as .020 and would misfire under load. The advance curve was stupid long too. If I had timing set to 10 degrees BTDC, the total came in 38 degrees and the car knocked under full throttle. If I backed it down to 4-5 degrees BTDC, it wouldn’t knock but was sluggish to accelerate. It was then that I learned about distributor tuning. I had to shorten the range of the advance. Through a series of mistakes, I did stumble upon some help and was able to adjust the guts to limit the range to 14-15 degrees. For years now I’ve either had initial at 17 and a total around 31 or 19 and around 33.
This MP distributor though… on the outside it looks stock but inside it is a scaled down aftermarket design with small, light weights and springs. For years, Rick Ehrenberg has criticized the design, saying the design sucks and the light weights result in unstable timing and spark scatter. Mopar Performance stopped selling these electronic conversion kits a few years ago but a few others have stepped up to fill the void for those that wanted electronic ignition but didn’t want the huge MSD box or didn’t want to go the Pertronix route.
Not long ago, Ehrenberg began selling ignition stuff through eBay. Maybe a year or so ago, a guy on this forum advertised a kit he got from the Rick store. He didn’t use it since he decided to use a later Hemi. I bought the kit for a good price and just stowed it.
Last night at our monthly Mopar club meeting, a member put out this for the raffle:

This is the same model as the one I bought awhile back. The guy gave it up because he found that if you invert it like this….

The shaft will spin but sometimes stops and won’t spin unless you twist it harder. Something is making contact inside. It doesn’t do this when standing up normally. We told the club guy that unless he drives his car upside down he would be fine. He contacted Rick E and the man just sent him another and said to just keep the “bad” one.
I don’t think it is terminal… I’m going to take it apart and see where it is making contact. The reluctor and pickup are not touching at any of the 8 points. It is below the “breaker plate”.

 

[Kern Dog]

For my Jigsaw Charger, I had a nice stock 400 electronic distributor. I did the old school trick of welding up the slots on the T bar.

Now I don’t pretend to be an expert on this. I’m just a guy that jumps in and fiddles around until I break or fix stuff.
Welding the slots works but you have to take the distributor apart to do it. If you weld too much, you just take a round file and saw it open more. I welded up about half of the opening because I figured that I only needed about 14 degrees of the 28 degrees of advance the distributors often have.
For my first effort, it worked. Jigsaw idles at 18 BTDC. And tops out at 32 degrees. This is an iron head 383 with 9.2 compression and 91 octane gas. It has not detonated yet.

Yeah, it is ratty but it runs great and is reliable. I have not had a single “no spark” issue. If it has gas and a battery, it fires up and runs.
This car though…

Over the years, it has had a random condition where it will have no spark. This can happen at first fire after sitting, a warm restart after running fine, cold weather, warm weather, it is just random. Sometimes I walk away and come back later and it just starts normally after getting no spark an hour earlier. It is like Christine where the car just refuses to run. I’ve traded coils, ECMs, ballast resistors and sometimes I’m fooled into thinking the part I swapped made the difference because it suddenly starts normally. I’m sure you can understand my frustration. A couple of weeks ago I cleaned the bulkhead wiring and packed in some dielectric grease and yeah, it starts but I keep wondering if OR when this no spark issue may return.

 

[twecomm]

I had converted from points using the Mopar Performance distributor / electronic ignition system back in 2011 on my 383. Was fine for about 6K miles and became problematic. Engine started running erratically. Checked reluctor clearance, perfect. Swaped orange box with a spare I had, same... It seemed to me that the shaft became sloppy in the casting, perhaps a bearing issue ? Anyways, decide to go with a FireCore distributor which is compatible with "the Mopar orange box". Glad I did as it resolved all my issues and has been problem free since 2011. Chrysler Electronic Distributors - FireCore Performance At least that's my opinion on distributors.

 

[Kern Dog]

It is mostly apart.

I see no contact marks on the plates.

 

[Kern Dog]

The vacuum can seems fine.

Down to this, it seems to spin freely.

You can see it has one stiff and one light spring.
I’ll reassemble it and see if it still makes contact.

 

[pnora]

Is the clip in place on the center of the shaft?

 

[Kern Dog]

Here it is. With the breaker plate back on, it makes contact again.
I had it back together complete with the vacuum can and still couldn’t see where it was touching. I pulled the can…

Big window now to see through and….

One peg on one of the advance weights was touching a rivet.

Center of the picture…

Upside down. The one with the black triangle spring.

You can see the gold anodizing worn away.

Looks like I can file a few thousands off and clear the T bar.

 

[Kern Dog]

Is the clip in place on the center of the shaft?

I don’t see any clip.

When I took that fibrous washer out of the inside of the shaft, I saw this:

Different way to retain the T bar but it seems okay.
I’ll file that rivet end a bit and test.

 

[Kern Dog]

Boom.

No more contact. It clears.
Score!
Here is one though…. The reluctor wheel isn’t indexed with any sort of key way.

I did mark it and pressed it back into the same position but it has 8 points that are evenly spaced to match the distributor cap terminals. I don’t understand how these can be in the right place for each one. The rotor is indexed.
Can someone explain that for me?

 

[Kern Dog]

Here is my point.
The first picture is the distributor I’ve just reassembled. The rotor tip lines up with the vacuum can. See The reluctor and pickup coil.

The reluctor terminal point is slightly away from the pickup.

Now the untouched RE distributor I bought from a FBBO member.

Rotor pointed the same yet now the points align. What issue could this cause? Would the distributor just have to clock one direction or the other and sit slightly different from the other but still work correctly?

 

[pnora]

Boom.

View attachment 1640560

View attachment 1640561


View attachment 1640562

View attachment 1640563

No more contact. It clears.
Score!
Here is one though…. The reluctor wheel isn’t indexed with any sort of key way.

View attachment 1640565
View attachment 1640566

I did mark it and pressed it back into the same position but it has 8 points that are evenly spaced to match the distributor cap terminals. I don’t understand how these can be in the right place for each one. The rotor is indexed.
Can someone explain that for me?

Makes no sense. The reluctor has to be phased to the rotor.

 

[Kern Dog]

I would expect that too.

 

[R/T Boy 67]

The second to last picture in post 9 seems to show a slot in the reluctor that almost lines up with a slot below it, could there be a pin that goes in there? It is hard to tell from the picture.

 

[pnora]

The second to last picture in post 9 seems to show a slot in the reluctor that almost lines up with a slot below it, could there be a pin that goes in there? It is hard to tell from the picture.

I saw that to but figured he would of questioned that.

 

[Kern Dog]

Three distributors are shown below. All three with shaft in same position. You can see the roll pin in the reluctor lines up with the rotor notch in the end of the shaft.

The above is the RE distributor I had apart. I put the reluctor wheel back on as it was before. The one roll pin in the wheel (two are in the wheel) that is visible is in the center of the notch to index the rotor.
Here is spare Mopar Performance distributor.

Roll pin in center. This last picture is of the RE unit I bought awhile back.

The roll pin is slightly off center. The scribe line on the shaft is off center too.
All three have slightly different positions of the pointer on the reluctor despite the rotor tip being in the same position. I know the MP unit (brass shaft) works. I haven’t tried these other two yet.

 

[Fran Blacker]

Eberg was selling adjustable reductors with several slots to choose from, so you phase the reductor to rotor. You say there is no keyway. Just a press fit?

 

[DeltaV]

All three with shaft in sane position.

If it were insane position, then would it be a "dizzy"?



Sorry, I had to...I know how much you like the slang term for "distributor".

 

[Kern Dog]

I keep having to go back and correct that.
Phone posting is where I make most mistakes.

 

[Lefty71]

Interesting stuff regarding the reluctor positioning errors. One more thing to keep an eye out for. Thx for posting up.

 

[Kern Dog]

Here are 8 LA series distributors. The first one is off a bit.

The next one is off a bit too.

Most were aligned with the rotor notch, two were off a few degrees. Everything came from running vehicles, of course. For sure, tomorrow I’ll dig deeper.
I ordered an advance limiter plate and springs from FBO ignition. I plan to use the stuff to retain my desired advance limits. I obviously can’t have 28 degrees of advance.
I need to plot the rpm’s the curve currently starts and ends. I remember that there were guidelines on when you should be “All in” but I don’t remember them. It makes sense that if you can do it without detonation, you’d want to be Fully advanced before 3000 rpms.