suddenly a rough running engine

dont know, there was not a ballast on the coil when I purchased the car..
there is a spare wire in the loom at the coil...
Peter
Ballast resister is hidden in the loom on our cars. Best way to test is turn on ignition and use a volt meter on the low tension side of the coil. If 9v its ballasted and the electronics will have a hard time with the that in the new distributor. If it’s 12v it’s not ballasted and the problem lies somewhere else.
 
Is your car a series 2? From my experience the wire going to the coil is pink/white and is a ballast wire. It has a higher resistance resulting in 9 v to the coil. The second wire comes from the starter, so that when the starter is hit the coil gets a full 12V. See if your system requires 12V or 9V (my lumenition system is happy with 9v) Try running a temporary wire from the powered side of the fuse box to the coil to give 12v and see if she fires. I ended up bypassing my 9v wire completely and installing a ballast resistor, because over time the ballast wire can degrade and supply insufficient voltage. Good luck.
 
hi there, thank you fr your helpful replys, I will do the tests.
Q : when getting number one cylinder on TDC to set up dizzy cap and timing, the rocker is removed and No 1 plug.
When checking the valves for both being closed when at TDC, there was no rocking as per normal valve set up.
Is this because the engine has hydraulic valves?
Peter
 
Is your car a series 2? From my experience the wire going to the coil is pink/white and is a ballast wire. It has a higher resistance resulting in 9 v to the coil. The second wire comes from the starter, so that when the starter is hit the coil gets a full 12V. See if your system requires 12V or 9V (my lumenition system is happy with 9v) Try running a temporary wire from the powered side of the fuse box to the coil to give 12v and see if she fires. I ended up bypassing my 9v wire completely and installing a ballast resistor, because over time the ballast wire can degrade and supply insufficient voltage. Good luck.

not sure if series one or two?
mine is a 1976, P6B, V8, auto box, 4 door sedan.
 
hi there,

did the test with a meter and had 12 volts at the + side of the coil and nothing on the minus side.
Is that normal with the ignition turned on?
The spark is very weak and engine will not fire , even for a second, would have thought that having 8 , one-would catch alight?
Have not had a reply from simmonbbc (power-spark) people!

Peter

Q : when getting number one cylinder on TDC to set up dizzy cap and timing, the rocker is removed and No 1 plug.
When checking the valves for both being closed when at TDC, there was no rocking as per normal valve set up.
Is this because the engine has hydraulic valves?
 
hi there,

did the test with a meter and had 12 volts at the + side of the coil and nothing on the minus side.
Is that normal with the ignition turned on?
The spark is very weak and engine will not fire , even for a second, would have thought that having 8 , one-would catch alight?
Have not had a reply from simmonbbc (power-spark) people!

Peter

Q : when getting number one cylinder on TDC to set up dizzy cap and timing, the rocker is removed and No 1 plug.
When checking the valves for both being closed when at TDC, there was no rocking as per normal valve set up.
Is this because the engine has hydraulic valves?
Hey Butter fingers,

You should test as follows:

If you have points fitted rotate engine until they’re closed. Then measure voltage across the two wire that would be connected to low tension terminals of coil. Do this with them disconnected from coil. The ignition system switches the ground on and off to energize the coil.
 
Hey Butter fingers,

You should test as follows:

If you have points fitted rotate engine until they’re closed. Then measure voltage across the two wire that would be connected to low tension terminals of coil. Do this with them disconnected from coil. The ignition system switches the ground on and off to energize the coil.

hi there,
I have fitted a new electronic dizzy, no points type, problem is a very weak , intermittent spark..
have now had an informative reply from simonbbc (powerspark) people, so will do their recommended tests.
Peter
 
did a power-spark recommended test by earthing the coil via the minus terminal and measuring the voltage at the plus terminal with the
ignition on, my result was 3.65 volts, should be 12 volts, so the conclusion is that somehow the system still has a ballest fitted somewhere, but ware?
its interfering with the new dizzy and coil.
How can I get rid of the ballest thing?
 
So you're only getting 3.65v to the coil then? Try with a power wire direct from the fuse box to the +ve side. I suspect you have a ballast-wire in the loom? But even then 3.65V is too little and there must be another problem? In any case - run a new wire to the coil (temporarily) and see what happens?
 
did a power-spark recommended test by earthing the coil via the minus terminal and measuring the voltage at the plus terminal with the
ignition on, my result was 3.65 volts, should be 12 volts, so the conclusion is that somehow the system still has a ballest fitted somewhere, but ware?
its interfering with the new dizzy and coil.
How can I get rid of the ballest thing?
Yep, that’s not right! Sounds like the ballast resister has died. Rob1 suggestion is the way to go.
 
I should clarify - I suspect in your vehicle (as in mine) the coil wire IS the ballast resistor. There is a steel section from under the dash to some point in the loom (to create the resistance), but with standard wire either end. These degrade over time and start causing trouble. Just bypass it to start with to eliminate/prove it as a problem. I ended up running a new wire from the ignition switch to the coil. In my case I wanted to retain 9V so I also put in a standard resistor just before the coil. Make sure you use a decent gauge of wire to carry the amperage.
 
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sorry if I am wrong in thinking but is this a new install of a electric ignition kit ?
 
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I made a massive mistake with mine I did not disconnect that battery before fitting then wondered why there was no spark its a absolute must
to disconnect the battery before fitting
 
sorry if I am wrong in thinking but is this a new install of a electric ignition kit ?
yes..

had a reply from power-spark, David , my contact person, said the same as others, it appears that the ballest is still connected somewhere in the wiring
loom . He recommended to bypass and run a new wire direct from the ignition switch to the coil.
there are white 2 wires , joined together that connect to the plus terminal. One must be from the ignition, what is the other one for?
possibly from the starter motor?.
So if I run a new wire would I also connect the other wire together as well? that is the question!
Peter
 
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I made a massive mistake with mine I did not disconnect that battery before fitting then wondered why there was no spark its a absolute must
to disconnect the battery before fitting

mine has a cut off switch in the cab and is always turned off.
 
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