What's a Ballast Resistor for anyway???

[Joe Guilbeau]

Here again,

We are standing on the shoulders of those who walked before us.

When points were around, they found that the full voltage applied to the points from the battery would "burn-up" a set of points in a few hundred miles, so they reduced the voltage when the vehicle is running to reduce wear on the points. Also a large charge on the points would sometimes jump the points gap, not a good thing.

Thats all there is to it.

Joe

[M/Z]

OK, well that is good to know, but here is a follow up question. Do I need to keep the balast resister if I have switched to a point-less ignition?

[Don S]

Joe Guilbeau...
... Thats the way i saw it but I believe the life of the coil may also be involed :confused:

Good Luck and CUL.. ds..

[Joe Guilbeau]

http://yarchive.net/car/ignition.html

Read this stuff for some technical discussions...

[Desert Beast]

as far as i know ballast resistors are for HID headlights (to build up the voltage for the arc) :D

[Don S]

Originally posted by Joe Guilbeau:
http://yarchive.net/car/ignition.html

Read this stuff for some technical discussions...OK Joe... I've read half of it and will get back on the thread a little later. It also opened up another little avenue I would like to explore.

Good Luck … and CUL… ds..

[Don S]

. OK I read the whole artical
… I don’t consider myself as an electronic type person but I do have a general class Ham Ticket. The stock BID ignition in my ’76 401(and only used in '76 & '77) is still running with the original module. The article didn’t change my opinions about the ignition systems so perhaps I’m a little dull. The 5% ‘gains’ from converting to other ignition systems is not worth the hassles and expense until I start racing my FSJ in the Winston Cup. :D
… John De Armond’s article did bring up something of a physics – airflow question for me. The question is, if a piston cylinder has 175 psi at low 500 RPM would it gain or lose pressure at 3000 RPM ? I believe the air would have to move at a higher velocity and that would reduce the flow rate and compression pressure. :confused:

Here I have quotes of the high lights of the page.

Originally posted in John De Armond's article :
“BTW, if there is an indication that there is insufficient spark energy in a drag racing or other short term environment, one can increase the energy by reducing or eliminating the ballast resistor. The coil will likely overheat over the long term so don't do it on the street”.

“The total energy available with a Kettering system is proportional to the peak current in the primary and the coil inductance. This is why heavy current and large coils work better. Also why electronic ignition works better. It permits more primary current than can be handled by points”.

"We tested rise time, we tested voltage, we tested everything. These were all important, but only to ignitions that were weak. Sparks like flicking a Bic in a dark hangar are bad, sparks that blast the combustion chamber like Thor, god of thunder are good."
“I went so far as to build some apparatus where I could switch high voltage from a robust source to the plug. All the way up until I started melting the electrodes, I saw a small but definite increase in power”.

“In my research using motorcycle engines, I'd typically see an improvement pretty much across the RPM band of around 5% when moving from a stock-type system to a then-state of the art system”.

“The pressure of compression at the time of ignition raises the dielectric strength of the air and thus increases the necessary voltage”.Good Luck and ;) CUL.. ds..

[Mud Thrasher]

as far as i know ballast resistors are for HID headlights (to build up the voltage for the arc)
Desert beast: the ballast resistors act as a resistor to reduce voltage to the points type dist. AMC, instead of putting a ballast resistor in decided to go with a resistor wire installed into the wiring harness between the ign. key and the ign coil. It reduces the voltage the the ign coil when the engine is running. AMC only used ballast resistors in 1972. If your resistor wire is bad then instead of trying to find another resistor wire(i tried) you can get a ballast resistor and install it inline like i did. Which it's rated at 1.35 ohms.

[Crazy_Jeepman]

my 70 has had a ballast resistor for the points ignition...........I just threw it away.........Going HEI, I like the one wire simplicity of it.