What is a ballast resistor?

[Dirk35]

Revisiting after a search:

1. What is a ballast resistor, what does it do?

2. Do I need one?

3. If so, how do I hook it up?

Heres the info of what I have:

1935 Ford PU, Ford 302 with MSD Pro Billit Distributor with the little two wire plug. MSD Ignition box. Chevy Steering column with switch in the column. AC Delco Alternator with two spade terminals and one out-put post. JEGS Mini Starter for Ford. I still havent figured out  what wires to hook the starter solenoid yet.

[Dave]

Revisiting after a search:

1. What is a ballast resistor, what does it do?

2. Do I need one?

3. If so, how do I hook it up?

Heres the info of what I have:

1935 Ford PU, Ford 302 with MSD Pro Billit Distributor with the little two wire plug. MSD Ignition box. Chevy Steering column with switch in the column. AC Delco Alternator with two spade terminals and one out-put post. JEGS Mini Starter for Ford. I still havent figured out  what wires to hook the starter solenoid yet.

A ballast resistor is just a resistor that cuts the voltage to the coil from 12 volts to approx 6 volts. If you need one or not depends on the coil you have. Pertronix coils dont need them if i remember right but most gm ford  and chrysler do. On later gm cars they used a wire that in it self was a resister and they eliminated the resistor or at least thats what i was told. I used to use vw coils that had it build in but i cant remember what year they were..  The older gm products used another wire from the starter solonoid that gave 12 volts to the coil for starting and then swiched 6 volts on the run side. I hope im not confusing you lol. I have a mallory unilite and a mallory coil and it needs a resistor
Dave

[Jbird]

The MSD instructions should tell you if you need a ballast resistor.
I get them from NAPA, P/N DR794 it has a nice gold bracket for mounting. Some resistors actually mount through the ceramic insulation and are prone to cracking.
      Jbird

[Dirk35]

I Shouldve covered that too, its a MSD Blaster 2 coil.

Will I need it?

In all the MSD Instructions, it never even mentions a ballast resistor.

However I have a wire from the Haywire harness labeled Ballast resistor. The instructions say: "connect the brown (really cannot remember what color) labeled Ballast Resistor to the Ballast resistor if used in your application."

Very vague indeed.

I really need to call Haywire, but figured Id wait till after the Holiday.

[Dave]

I Shouldve covered that too, its a MSD Blaster 2 coil.

Will I need it?

In all the MSD Instructions, it never even mentions a ballast resistor.

However I have a wire from the Haywire harness labeled Ballast resistor. The instructions say: "connect the brown (really cannot remember what color) labeled Ballast Resistor to the Ballast resistor if used in your application."

Very vague indeed.

I really need to call Haywire, but figured Id wait till after the Holiday.

how about the msd web site ?
dave

[Dave]

Revisiting after a search:

1. What is a ballast resistor, what does it do?

2. Do I need one?

3. If so, how do I hook it up?

Heres the info of what I have:

1935 Ford PU, Ford 302 with MSD Pro Billit Distributor with the little two wire plug. MSD Ignition box. Chevy Steering column with switch in the column. AC Delco Alternator with two spade terminals and one out-put post. JEGS Mini Starter for Ford. I still havent figured out  what wires to hook the starter solenoid yet.

Sitting here waiting to go out for the afternoon deer hunt and thinking. Wonder who came up with the term ballast resistor and why? A resistor is a resistor There are different types but they all do the same thing. In the case of a ballast resistor its actually a wire wound resistor. How does it work??? It creates a resistance against voltage then in turn burns off the voltage in heat dropping the voltage. As you might have figured out by now the more resistance the more voltage drop. In the ham radio hobby we use a lot of carbon resistors. Carbon is used as a resistance material instead of a wound wire..Oh ya there are variable resistors also that can be adjusted to a certian resistance or change to accomadate a range of resistance. Im looking at my steering wheel for nascar racing and its got 4 in it.  How about a big carbon silicon carbide resistor for heating? We use em in a big oven at work. Same deal throw hi voltage at it and it burns it off in the form of heat..... Ok Enuff....
So why do they call it a ballast resistor? beats me but as long as I can remember thats what its been called........................

whats next ? Diodes zener Diodes.... ? How about i tell ya how i made the fm antenna for the radio in the 32 just like (well not as pretty but its hidden) the ones they sell for 40 bucks for about a buck? I really had fun with that one...

Dave
ps: im not braggin here that i know sumpin im amazed that i actually do . Now if i could just see another deer to shoot at:lol:

[enjenjo]

I really need to call Haywire, but figured Id wait till after the Holiday.

Haywire won't know, it depends on the coil and ignition used. I have a Mallory unilite in mine, and it uses two resistors. GM HEI, and Duraspark from Ford use none. Mopar electronic uses one, but it's not the same as GM Points type. Your best bet is to call MSD

[Land Yacht]

The original idea was to drop the battery voltage to the points, so they would last longer during running. When starting , it got bypassed so the coil would see full battery voltage. So the coil would have been designed to run on the reduced voltage on those applications.


In other circuits Ballast seems to do with compensating for something. Wire wound (I'm guessing) has to do with having a higher power rating.

[Bob Paulin]

A ballast resistor is a variable resistor....which differs from a simple resistor.

A simple resistor cuts voltage by a measured amount...for example 12 volts to 6 volts.

As a ballast resistor heats up, it offers MORE resistance....which is good in the case of breaker point ignition.

At slower engine speeds, the points remain closed for relatively longer periods of time, flowing more voltage through the ballast resistor, heating the ballast resistor up, creating more resistance, thus flowing less voltage through the points when they are closed longer, which lessens the burning of the points.

At higher engine speeds, the points remain closed for relatively shorter periods of time, so the ballast resistor doesn't flow voltage for as long a period of time, and cools off, allowing more voltage to the points for better spark from the coil due to higher primary winding saturation.

A thermistor is just the opposite....offering more resistance when it cools, and less when it heats up.

As one GM factory training man once said to me, it should be called a "Therm - missus", because the warmer it gets, the less resistance it offers.......

Voltage reduction is a benefit with breaker point ignitions in keeping the points from burning up.

Most non-breaker point ignitions are designed to operate on full system voltage.


B.P.

[WZ JUNK]

I have a mallory unilite and a mallory coil and it needs a resistor
Dave

Dave,  This is a timely question as this afternoon I am wiring a car with an Accel coil and a Unilite distributor.  I am thinking that the Unilite does not require the extra wire to the coil to supply the 12 volts for starting.  I think the feed wire for the ignition goes to the ballast resistor and that is all I need.  I was going to look this up but maybe someone can tell me if I am correct.
John

[Bib_Overalls]

I hate ballast resistors.  Years ago I had a Corvair powered dune buggy with a points distributor and ballast resistor.  The resistor got bumped and the positive part  made contact with one of the grounded mounting bolts.  The positive lead from the ignition fried and I wound up replacing all of the wires to and from the ignition switch.  My current rod has a "Dave's Small Body HEI" and no ballast.  I'm happy.

[enjenjo]

I have a mallory unilite and a mallory coil and it needs a resistor
Dave

Dave,  This is a timely question as this afternoon I am wiring a car with an Accel coil and a Unilite distributor.  I am thinking that the Unilite does not require the extra wire to the coil to supply the 12 volts for starting.  I think the feed wire for the ignition goes to the ballast resistor and that is all I need.  I was going to look this up but maybe someone can tell me if I am correct.
John

I use two DR125 resistors with a Unilite ignition, hooked in series. This was recommended to me by Mallory some time back. I have never had any trouble using this setup, and have never had one fail. My Marlin has been that way for 14 years now. I did have a Mallory coil fail on that, come to find out my supplier sent the wrong one, points type coil instead of an electronic coil.

[kb426]

The ford sel. has 2 large post and 2 small posts. The large are battery in and starter out. The 2 small posts are extra voltage when cranking to the coil and the other one energizies the sel.

[C9]

I have a mallory unilite and a mallory coil and it needs a resistor
Dave

Dave,  This is a timely question as this afternoon I am wiring a car with an Accel coil and a Unilite distributor.  I am thinking that the Unilite does not require the extra wire to the coil to supply the 12 volts for starting.  I think the feed wire for the ignition goes to the ballast resistor and that is all I need.  I was going to look this up but maybe someone can tell me if I am correct.
John[/quote]


Here's some good tech info as well as wiring schematics for a number of Mallory products.

Just select what you want when you get there.
If I remember right it's a PDF file which requires Adobe Reader.
Adobe Reader is free and if you don't have it, the site will ask you if you want to download Adobe Reader.

Be advised that it can take a little while (1-2 minutes on dialup) to download the Mallory information, but it's worth the wait.

http://www.centuryperformance.com/mallory/mallorytech.asp[/url]

[Dave]

I have a mallory unilite and a mallory coil and it needs a resistor
Dave

Dave,  This is a timely question as this afternoon I am wiring a car with an Accel coil and a Unilite distributor.  I am thinking that the Unilite does not require the extra wire to the coil to supply the 12 volts for starting.  I think the feed wire for the ignition goes to the ballast resistor and that is all I need.  I was going to look this up but maybe someone can tell me if I am correct.
John[/quote]
Yes you only need one wire for the Mallory..
Sorry I didnt get bact to you but I was out playing in the swamp half the night

 I love tracking....
Dave