+/- 2 it's not a digital. (It might be a bit old school too.)
Points and Condenser Again
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Now, the item that is still odd: You indicated the C+ voltage is the same when cranking and running. (But, that is possible if there's a low battery voltage when cranking, and a much higher alternator voltage when running.). While idling, can you check the alternator voltage (should be about 13.5, more or less) and compare that to the reading you get on the coil C+ terminal (which should be lower, 7-9v, due to the dwell current pulses through the resistance wire, and averaged out in your meter circuitry)?
Thread Starter
Racer
Joined: Aug 2013
Posts: 358
Likes: 23
From: Brigantine NJ USA
While idling, can you check the alternator voltage (should be about 13.5, more or less) and compare that to the reading you get on the coil C+ terminal (which should be lower, 7-9v, due to the dwell current pulses through the resistance wire, and averaged out in your meter circuitry)?
On the same analog voltmeter while idling 14.5 volts at alternator, 12 volts on positive at coil.
Using a digital timing light voltmeter see below
Digital timing light voltmeter while idling 14.7 volts at alternator, 14-7 volts (jumps back & forth) on positive at coil.
Reading from Positive side coil
Key on no digital reading (analog voltmeter 8 volts)
Cranking digital 9.7-10.5 volts (Distributor coil wire removed from dist. Cap)
Running digital 13-7 volts jumps back & forth
With key on reading positive terminal on coil no digital volts reading (7.5 on analog voltmeter) then digital 12.2 volts with the points separated with thin cardboard.
Rick
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Below is supplied a bit more accurately
On the same analog voltmeter while idling 14.5 volts at alternator, 12 volts on positive at coil.
Using a digital timing light voltmeter see below
Digital timing light voltmeter while idling 14.7 volts at alternator, 14-7 volts (jumps back & forth) on positive at coil.
Reading from Positive side coil
Key on no digital reading (analog voltmeter 8 volts)
Cranking digital 9.7-10.5 volts (Distributor coil wire removed from dist. Cap)
Running digital 13-7 volts jumps back & forth
With key on reading positive terminal on coil no digital volts reading (7.5 on analog voltmeter) then digital 12.2 volts with the points separated with thin cardboard.
Rick
On the same analog voltmeter while idling 14.5 volts at alternator, 12 volts on positive at coil.
Using a digital timing light voltmeter see below
Digital timing light voltmeter while idling 14.7 volts at alternator, 14-7 volts (jumps back & forth) on positive at coil.
Reading from Positive side coil
Key on no digital reading (analog voltmeter 8 volts)
Cranking digital 9.7-10.5 volts (Distributor coil wire removed from dist. Cap)
Running digital 13-7 volts jumps back & forth
With key on reading positive terminal on coil no digital volts reading (7.5 on analog voltmeter) then digital 12.2 volts with the points separated with thin cardboard.
Rick
Your C+ voltage reading is frequently higher than expected. Can you get a decent resistance reading of the coil primary winding?
Thread Starter
Racer
Joined: Aug 2013
Posts: 358
Likes: 23
From: Brigantine NJ USA
Okay now with a high accuracy digital voltmeter
Positive side coil
Key on 6 volts, 12 volts with the points separated with thin cardboard
Cranking 9.9 volts (Distributor coil wire removed from dist. Cap)
Engine running 10.8 volts
At Alternator
Engine off 12.4 volts
Idle 14.7 volts
1.5 ohms
Do you see my data as acceptable or an issue?
Rick
Positive side coil
Key on 6 volts, 12 volts with the points separated with thin cardboard
Cranking 9.9 volts (Distributor coil wire removed from dist. Cap)
Engine running 10.8 volts
At Alternator
Engine off 12.4 volts
Idle 14.7 volts
1.5 ohms
Do you see my data as acceptable or an issue?
Rick
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Okay now with a high accuracy digital voltmeter
Positive side coil
Key on 6 volts, 12 volts with the points separated with thin cardboard Yup, looks good.
Cranking 9.9 volts (Distributor coil wire removed from dist. Cap) In the ballpark.
Engine running 10.8 volts Given the higher end alternator voltage, that looks to be mathematically correct.
At Alternator
Engine off 12.4 volts
Idle 14.7 volts "Cold" voltage, I'm assuming. I believe this voltage is supposed to drop down to about 13.2-13.5 volts when the engine/alternator gets warm, making life easier on the battery and electricals.
1.5 ohms Typical. Good.
Do you see my data as acceptable or an issue?
Rick
Positive side coil
Key on 6 volts, 12 volts with the points separated with thin cardboard Yup, looks good.
Cranking 9.9 volts (Distributor coil wire removed from dist. Cap) In the ballpark.
Engine running 10.8 volts Given the higher end alternator voltage, that looks to be mathematically correct.
At Alternator
Engine off 12.4 volts
Idle 14.7 volts "Cold" voltage, I'm assuming. I believe this voltage is supposed to drop down to about 13.2-13.5 volts when the engine/alternator gets warm, making life easier on the battery and electricals.
1.5 ohms Typical. Good.
Do you see my data as acceptable or an issue?
Rick
Thread Starter
Racer
Joined: Aug 2013
Posts: 358
Likes: 23
From: Brigantine NJ USA
Mike Thanks, I'll rule out the voltage issue.
Going back to the beginning of this thread regarding “Lemons” I’m back to focusing on the points and condenser. Reading thought the forum it seems Standard Motor Products (SMP) manufactures Napa's Echlin brand and others as well as BWD so I'll give those a try.
Thanks for everyone's input.
Rick
Going back to the beginning of this thread regarding “Lemons” I’m back to focusing on the points and condenser. Reading thought the forum it seems Standard Motor Products (SMP) manufactures Napa's Echlin brand and others as well as BWD so I'll give those a try.
Thanks for everyone's input.
Rick
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