CHRYSLER spark plugs?

ok i was going to comment on some one elses tread but i thot i would make my own. i know for the origonal chrysler cdi system and distributer you need to use the surface fire spark plugs, but i often convert these motors to car coils, and should i still run the surface fires with the car coil conversion? I have always believed that the surface fires wanted more voltage and would kill the coil faster than normal. i have ran these motors with the car coil conversion, with and without surface fires and if any body know the best way (Frank) thanks!

Re: CHRYSLER spark plugs?

by the way i almost always use old bosch coils off of '80's volks wagens becasue i got a bunch of them, or i commonly see ford coils. niether of these need ballast resistors. but what is best for external ballast resistor, and none external resistor?

Re: CHRYSLER spark plugs?

can you difine what you mean by "convert to car coils" do you mean just replace the original coil and leave the cdi unit in place
The bosch coils are essentially 6v coils ..you can check the primary and if its 1.5 ohms its a 6v and 3 ohms its a 12v ( join your meter probes and subtract that reading when testing the coil ) The ford ballasted coils were also simple 6v coils.

What plugs did you substitute for the surface discharge type?

Re: CHRYSLER spark plugs?

you remove the cdi and coil (fried) that chrysler put on, and you replace it with a car coil and condensor, sot hen your ignition system is pretty much the say as any old car, distibuter ran coil and condensor. and i use champion L77 JC4 (im pretty sure thats what they are, or they might be for my 18hp evinrudes i forget, lol) but anyways i use th ebent electrode style

Re: CHRYSLER spark plugs?

if you are using the 1.5 ohm bosch coils without a ballast resistor on 12v then the contacts will not last long ..on a car I would say 1000 miles .The coil will draw 8A !!! Best fit a ballast resistor
.. all makes of ballast resistor from the 70s are the same .. they are 1.5 ohms each . Without one your modification will let you down for certain. Do not be misled if the coil is marked 12v that only means for use on a vehicle with a 12v battery ..checking the primary resistance is the definative test .

Re: CHRYSLER spark plugs?

i know i run ballast resistors on them(im a chrysler fan through and through and have many spares for chrysler cars) I have been using the bosch coil for 2 summers, with no problems what so ever, motor starts as soon as the starter touches the flywheel. but were not discussing coils, we are duiscussing what plugs should i use on the car coil conversion, i ran surface fire plugs for 1 summer, and found it was erroding the plug, i swapped out to bent electrode type and found smoother idle, (not that i cared) and the plugs havent been changed once. after probably, $2000 in gas @ $1.50-1.60 a litre. what i want to know is is ther any ill effects of running bent electrode, i dont mind if i haved to put a plug or 3 in every once and a while,

Re: CHRYSLER spark plugs?

acctually i think the spark plugs i use are champion J-4J (bent electrode style)

Re: CHRYSLER spark plugs?

Good on the ballast resistors ...others might try the mod and not realize they need the resistors hence my comment ..if you want to know how to fit a bypass cable to give extra volts for starting without changing the solenoid let me know.
If you have run that much gas on bent electrode plugs then all should be fine ..I am convinced that the people who have had problems have had the timing wrong or fitted too hot a plug...the surface discharge plugs are intended for an AC spark which moves metal one way then back ...the coil system is only centre to side spark ......glad it runs well