The Stovebolt Site Forums The Shop Area Engine Shop Ballast resister, do I need one?

Fried two point sets, switched to a Pertronics Ignitor, engine runs, but sluggish, low power under load. No Resister in line with coil, cked voltage thru coil, 12 volts, cked ohms resistance 1.5 ohms, pertronics manual says 4 ohms for six cylinder, my calcs says I have 8 ohms, do I need a ballast resister? If so what value? Engine 235 six 12 volt system.
Any Freddy Kilowatts out there got an idea?

The purpose of a ballast resistor is to lower the voltage across the points, extending their life. During startup, the resistor is bypassed, to send more voltage through the coil for easier starting. Once the engine is started, the ballast resistor comes into play.

Some coils come with a builtin resistor.

However, Pertronics devices don't even have points.

You might replace the coil with a higher voltage one for better spark, but sluggish under load sounds like a fuel-air mixture problem or a timing problem, not a spark problem.

Thw Eagle speaks the truth. Install a ballast resistor and your points problems should end.

1SG,

Are you asking about the need of a ballast resistor with points or with the Pertronix unit?

What is the brand and part number of your coil?
What is the part number of your Pertronix unit?
What is the year of your engine (and the year of your distributor)?

Thanks for the info, but ballast resistors come in different values, trying to get correct resistance to pertronics ignitor.

Tim, 1961 distributer #1112388, 1961 engine, pertronics unit #1168LS, coil Delco#165 12V. 54 3100 5-window w/hydra-matic.

Paul, truck runs like a raped ape with points and condenser, installed pertronics unit, low power, sluggish....

According to the Pertronix website, if you have a 1.5 ohm coil @12v =8 amps. No ballast resistor is needed.

http://www.pertronix.com/support/tips/default.aspx#a2

Forty9,
8 amps for 8 cyl......4 amps for 4&6 cylinders....

I agree with Ed, take out the ballast resistor and see how it runs?

Tim, am I stating something wrong here? There is not a ballast resistor in the system now, never has been.

and what folks are saying is if you'd had the ignition resistor on your points system, you wouldn't have fried 2 sets of points, a '61 12V points system uses the resistor [STANDARD MOTOR PRODUCTS # RU10] or an internally resisted coil - are you sure you don't have an internally resisted coil? - the ballast resistor has nothing to do with the resistance of the coil itself - if you "checked" the resistance of the coil at 1.5 ohms, how did you "calculate it" to be 8 ohms?

Bill

Bill, I didn't calculate it to be 8 ohms, I calculate it to be 8 amps, here is copy of pertronics formula. I just happen to have the exact voltage and resistance they show, they state 4 amps max for 6 cylinder....

Example
Voltage 12
Resistance 1.5
12 / 1.5 = 8
Total amperage 8

your first post says ohms, not amps .... I think you might find using that formula with 6V would yield the stated 4 amps - did you get a kit for a 6V system?

Bill

I'm using a 40511 On a set up similar to yours.


New plugs-increased gap, wires, rotor, and cap is recommended when switching.

Your performance issues could be something else's

Sorry Bill I screwed up I meant to say 8amps in original post, my bad....nope got a 12 volt kit, the coil on board is old Delco original, no resistor model. I sent Pertonics my findings with the tests they recommend via email, they sent back the same tests that are on there website, duh, never answered my question about a resistor....

DADS50 all new items you mentioned, except plug gap is 35 thousands at present....

the coil DADS is using says 3 ohms, which would give you the 4 amps, might consider a new coil, with everything else new

Bill

Roger that Bill....

Pertronix recommends increasing plug gap .005 over factory.

My 235 runs best with timing advanced 8 degrees.