No Spark? '31-12V

B

bgalla

Member
One should be able to get a reasonable spark out of a coil with the ignition on and with access to the points opening them. Right! I have held the coil to distributor cap wire close to a good ground and nothing! Could a bad condenser do this? Or is it more likely the coil. There is a resistor interposed between the terminal box and the coil on the Black wire. Other than converting it to 12V it is totally stock. thanks Bruce
 
Is this monster + or - grd ? Not that it matter that much for your problem, but, whatever the battery ground is, it should be the same thru the points.

Do you have voltage to the open point arm when key is on ? It should be about 8 volts if you have the correct coil or external ballast resistor, whichever you're using. If you have no voltage then work back until you do and you'll find the problem. If you have voltage then make sure there is none when the points close. Most of the no spark issues are in the primary circuit somewhere.

Yes, a bad condenser could cause no spark.

How much of a gap are you trying to jump ? 1/4" will do.
 
Patrick: It is a negative grd. When you say "open arm of the points" do you mean open to current with the points closed or should the moveable point arm be open. I may have to refresh my knowledge of how the spark is generated. thanks Bruce
 
With key on there should be voltage to the moveable point arm when it is open [high point on cam showing an air gap] . That indicates there are no problems such as opens or grounds in the primary circuit.

When points are closed there should be no voltage indicating that the stationary point contact is grounded.

With a 12v negative grd system, the coil primary wires will need to be reversed. The negative coil wire will be to end up going to the points.

You'll need to know what type coil you are using. Does it contain a resistor, it not, you'll need to and an external ballast. It'll either be a 1.5 ohm or 3.0 ohm coil. If its oil filled then it should be mounted with the secondary coil wire pointing to the sky.
 
Use a point file or piece of emery cloth folded double to clean the points. Hand crank the engine over until points are closed, then turn on ignition. Use a wood splinter to snap the points open/closed. Should get a nice hot blue spark off the coil wire.
 
bgalla said:
One should be able to get a reasonable spark out of a coil with the ignition on and with access to the points opening them. Right! I have held the coil to distributor cap wire close to a good ground and nothing! Could a bad condenser do this? Or is it more likely the coil. There is a resistor interposed between the terminal box and the coil on the Black wire. Other than converting it to 12V it is totally stock. thanks Bruce
Click to expand...


It could but if the condenser has been made in the last 10 years most likely not.


What has changed? Did it ever work on 12 volts? If you put a piece of paper between the points do you have voltage at the movable arm to a head nut? If so what is the voltage?
 
Have you checked both primary and secondary windings of the coil for continuity w/an ohmmeter?
 
eagle said:
Use a point file or piece of emery cloth folded double to clean the points. Hand crank the engine over until points are closed, then turn on ignition. Use a wood splinter to snap the points open/closed. Should get a nice hot blue spark off the coil wire.
Click to expand...
Very true! Even a little dirt/grease/what not will cause no fire.
 
I agree , I always clean and lightly sand new points , If nothing else , sanding will remove any glaze on the contacts . As for the condenser , If you are using the original style A&L condenser that the better model A vendors sell , its not likely that the condenser will be the problem . I have often called the so called modern points setup a make shift rig . The V8 points are no advantage at all and are difficult to adjust . I always eventually had problems with them . The wireless lower plate that is often used with the V8 points can easily short against the housing . Its your choice but I would recommend switching back to the original points set up. I had lots of trouble with the low cost ignition switch. I had to change to the slightly over fifty dollar switch for dependability . When you set the timing , Set it like Tom Wesenburgs pic. Any rotational backlash in the distributor shaft should be in the counter clockwise direction where it will have no retarding effect on the timing when the cam screw is tightened . Any clockwise back lash in the distributor shaft after the screw is tightened will cause the timing to be retarded . The reason clockwise backlash causes retarded timing is the engine will have to turn to catch up the backlash .
 
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