electronic ignition help...

Hi guys,

At a swap meet last weekend I picked up a neat little piece, it's a
Studebaker V-8 distributor with the guts from a B/RB MoPar distributor
swapped in so that I can have a fully electronic ignition. (I was
actually trying to build one of these for another project last year but
I got to the stage where I had all the parts laid out and that was about
it... other things got in the way of me finishing that project..)

ANYWAY... the questions. I have the distributor, the wiring harness,
and the orange control box. So far so good. Did not have a ballast
resistor so I went to the parts store and got one for a '73 Chrysler, I
figured that would be about right. When I opened up the box to look at
it there are four terminals on it... all the wiring diagrams for this
setup that I have found online show a single ballast with two
terminals... what gives? I'd actually like to install this next weekend
as I am having driveability problems in my '55 Stude coupe and would
like to eliminate the distributor as a possibility.

thanks,

nate

 

Ohm both sides of the resistor, one will be 5 ohms, one will be
1.2 ohms or so. Use the 1.2 ohm side as described in the wiring
diagrams that you found. This all assumes that your orange
control box has 4 pin terminals instead of 5.

-Or- go back to the FLAPS and have them pull a ballast resistor
for a 1979 Pick Up truck with a 360 engine. That should yield a
single ballast resistor. (Echlin # ICR23)

Make absolutely certain that the control box is well grounded,
run a braided ground wire between it and the engine block.

Mount the control box so it will receive some air flow to help
keep things cool. (inner fender, firewall, radiator support)

 

Ayup, the instructions say to disregard one of the wires in the harness
(the kit was never installed in a car, the guy just lost the ballast
resistor) so I am ASSuming you are correct.

Thanks! That should get me going. Now to find some free time to run
out and work on the beast again...

Just curious, what is the 5 ohm resistor for? ISTR a discussion about
this a while back but don't recall the answer.

nate

 

Yeah, good luck getting that orange box to work reliably and last. They
were good some years back (though no better than the stock box, flowery MP
catalogue description notwithstanding); they got shittier a few years
after introduction. Early failures are not uncommon.

When(!) the orange box in my '62 fails, I'm going to swap in an HEI
module. It's a dead-simple swap, supports larger plug gaps and requires no
ballast resistor -- two real improvements.

That'd be a dual resistor, which is not what is needed with the 4-pin
Mopar modules. The dual resistor is used with the 5-pin modules.

DS

 

I never had one fail nor have anyone I know???
Dodgem

 

I've had numerous failures of the MP boxes, both orange and
chrome as have friends who opted for the conversion.

I switched to the Echlin brand, now at least when they fail, the
parts store will warranty them.

 

IIRC, the 5 ohm resistor controls current to the base of the
switching transistor, the 5 ohm resistor is now (on the 4 pin)
mounted internally to the ECU making failure a box replacement
instead of a ballast resistor replacement.

Carry a spare. Seems the best way to ward off evil spirits.

 

I have heard of that swap, and also am told that any number of
aftermarket ignitions can be triggered by the distributor directly
without a module... but I have the orange box now so I might as well
give it a try. I thought however that the ballast resistor was more
for the coil than for the module, i.e. if I use the stock Prestolite
coil I still need the ballast; if I use an aftermarket coil with an
internal resistor I don't need a ballast, yes? I was thinking it would
be preferable to keep the ballast resistor esp. since I am using an
Avanti (4-pole) starter so that I could install a bypass wire from the
starter solenoid. (right now I am using the stock 6V wiring and a
cheap aftermarket coil with internal resistance, but I'm not so much a
purist that I won't do a little modification to the wiring harness.)

Just for curiosity's sake, can someone explain this to me or point me
to an explanation?

thanks

nate

 

Measure both sides with an ohmmeter, and then connect to the LOWER
resistance side. The other side was only used in EI systems through
about 1975 (? or somewhere around there). Its a resistor that is
internal on the newer electronic ignition boxes, which you can identify
because they only have 4 pins in the 5-pin connector.

 

AH now it kind of makes sense. So the higher resistance resistor in
the dual ballast is some kind of power supply for the old control box
which would be wired to the pin which is now unused on the newer boxes,
yes?

thanks guys for all the help

nate

 

I don't know what it has for a shaft, I guess none or you will add
one.
Remember, the RB has a longer shaft than the B.

Ah, yes, I remember it well.

You can use either a 4 or 5 wire module.

Single ballast (.5 ohm) goes between the key and coil positive.
2nd resistor in blocks supplies pull-up current to something in the
module. 4 pin boxes have that resistor inside the box.

This shouldn't make it run much better, unless something
is wrong with the original distributor.

 

Close, .5 ohm and 5 ohm.
The .5 ohm one is the one that gets hot and fails.

I wouldn't do that, some that vintage are 1 ohm.
You need .5 ohm.
One for a 61-72 Mopar (excluding dual-point
Prestolite ignition) would be the choice.
Or use the 4 pin resistor with the 5 ohm resistor
connected or not.
Do you have a FSM for a 73-78 Mopar?

One of the 4 wires is a ground, ground that while "making"
the harness.

 

Using the stock Studebaker shaft and housing. The "head" of the dist.
is the same as the old MoPars, just the housing and shaft are different.
Specified B/RB because they rotate the same direction.

nate

 

Heh, sounds familiar... some things never change (that was the first
advice I gave to my ex-GF when she bought her '69 Valiant...)

nate

 

oh yeah forgot to respond to this bit. There likely *is* something
wrong with this distributor, as determined after a bit of back and
forth on another newsgroup with the MoPar faithful... apparently the
Studebaker-spec Autolite/Prestolite distributors used laminated steel
advance weights without bushings, whereas the MoPar spec ones used
weights with Oilite bushings pressed in... so the Studebaker ones have
a real bad reputation for poor operation after only a few tens of
thousands of miles whereas the MoPar guys apparently have no idea what
we're bitching about as the MoPar ones work fine until the thing just
falls apart from old age.

Now to digress a little bit... Studebaker also used Delco distributors
for various models, both early and "window" flavors, and while those
have a good reputation for durability at least one person who messes
with performance parts for Studes (and the guy that put together this
conversion that I bought, coincidentally (?) enough) swears that the
Delco has a lot more variation in spark timing than a Prestolite in
good condition. Not having an oscilloscope I don't have the ability to
confirm/deny that but it costs little to buy "junk" MoPar stuff and
mess with it (before you take offense I am not implying anything
about MoPars, I used to drive a slant six Dart once upon a time and had
a lot of respect for the car, I just mean old parts that *others* think
are junk...)

nate

 

Hey!!!

The greatest thing in the world is to find a guy with 5 Mopar parts
buried in a truckload of Chevy stuff at a swap meet. I know people that
have picked up HP exhaust manifolds for $5 each, and 906 cylinder heads
for $10 apiece that way

 

Both sides can and do fail, and you'll have a hard time finding a
dual ballast with a .5 ohm side since all that appears to be
available currently is 1.2/5 ohm.

Wanna take a guess what ohmic value resistor MoPar Performance
has been shipping with their electronic ignition conversion kits
for the last 20 or so years?
Besides, dropping the ballast resistor value does nothing more
than shorten the dwell time, coil saturation remains unchanged,
coil failure can be expected from over current though.

Let's see... 4 wire ignition box
2 are for the pick-up coil
1 goes to the coil negative
1 goes to the J2 ignition on hot

Which one is the ground again?

Yeah, I've got a few mid 70s FSMs, I was working in a Chrysler-
Plymouth dealership when these systems were as common as factory
closings.

 

1978 (just FYI while I'm here)

Yes.

 

Don't use a coil with an internal resistor. Keep the ballast
resistor idea. You could make a ballast bypass with one
of those Bosch relays, or other.
I'm not familiar with your starter.
OH, does Avanti mean a ~1964 GM starter with solenoid?
If yes, yes, you could use the ballast terminal for the bypass.
(4-pole is likely a wrong description)

You can use a 4 pin ballast with a 5 pin module, the extra resistor
won't be connected (through the module's missing pin).
If you use a 4 pin ballast, you can use almost any module.
If you use a 2 pin ballast you will not be able to use a 5 pin
module.

 

Of course. I should have figured that.