My story starts on my way to work. I drive 50 miles each way and thought it was a nice day to drive my 67 Dart Convertible. 3/4 way there the engine started to misfire. At first it was a stumble, then more misfires, then some backfires, then lack of power barely able to move under its own power. Luckily I got it to my work safely.
For the record... plugs, wires, dist cap, rotor, points, condenser, were replaced 2 months ago. Carb was rebuilt at the same time. I did not replace the coil ( I think it is the original as it says made in the USA and has flats on the + and - posts)
That afternoon I looked at the symptoms and possible causes.
1. The timing chain had been replaced 10,000 miles ago and when the engine is rotated by hand the rotor moved instantaneously in either direction. Most likely not the timing chain.
2. The distributor cap inside center contact was destroyed, instead of a rounded point it looked more like the top of a molar in you mouth. Likely reason for a misfire.
3. Rotor had a round doughnut pattern to the contact where it contacts the cap center contact. probably due to the destruction of the center contact.
4. Points looked good and I had 30 deg dwell.
5. Spark was strong but not consistent ( what you would expect from an electrical misfire)
6. Accelerator pump shot fuel into the carb
7. No gushing of fuel into the carb at idle or off idle
8. 12 V to the ballast resistor.
9. 6-8 volts at the coil while running
10. Ignition timing was right where it was supposed to be.
11. tried advancing and retarding, no improvement
Off to the parts store...
Bought cap, rotor, coil. Replaced the parts and no improvement.
Being 50 miles from home and having limited tools and time I had the Dart towed home $$$.
Today I started doing more investigation.
1. checked ballast resistor. functioned correctly
2. opened carb, everything looked and functioned good
3. disconnected the coil capacitor, no improvement
4. disconnected the condenser, no improvement but I did notice the lead wire from the coil to the points felt odd.
5. replaced the lead wire, no improvement.
6. replaced the capacitor and condenser and of course dropped a nut into the dist!!!
7. pulled the dist to retrieve the nut.
I found the dist shaft had end play up and down. seemed excessive but I had nothing to compare it to so I assumed it was normal. I noticed that the inside of the dist had metal or other dust / fragments in the bottom, and a circle where it looked like the bottom of the plate that holds the centrifugal weights and springs might have been ribbing. I cleaned it out and reassembled and lubed the dist and put it back into the engine.
Still major misfire.
I started investigating how much end play is too much when I remembered that my dad had kept the original dist (not sure why he replaced it with the one in the engine now) so I pulled it out to see if it had end play. Barely any... maybe a few thousandths I thought what the heck and swapped it in (the old dist has sat in a box, points in place for 30 years and and it had 264,000 miles on it when it was removed in 1987)
turned key.... Fired right up. No misfire, no stumble, no issues.
I oiled the side oil port cap and took it for a spin. The dwell was 29 doesn't get better than that.
I looked at the old dist. it had 86 thousandths of play. My guess is that the shaft was moving up and down enough for the rotor to no longer make contact with the cap contact and throughing spark all over the place.
so why is this the tale of the $350.00 distributor....
Rotor, cap, coil, dwell tach meter ~ $50.00
Tow 50 miles on a flatbed ~$300.00
Replacement dist- Free
So the moral of the story.... Keep a spare Dist, 1/2 inch box wrench, 5/16 ignition wrench in the trunk. save your self $350.00!
Enjoy!
For the record... plugs, wires, dist cap, rotor, points, condenser, were replaced 2 months ago. Carb was rebuilt at the same time. I did not replace the coil ( I think it is the original as it says made in the USA and has flats on the + and - posts)
That afternoon I looked at the symptoms and possible causes.
1. The timing chain had been replaced 10,000 miles ago and when the engine is rotated by hand the rotor moved instantaneously in either direction. Most likely not the timing chain.
2. The distributor cap inside center contact was destroyed, instead of a rounded point it looked more like the top of a molar in you mouth. Likely reason for a misfire.
3. Rotor had a round doughnut pattern to the contact where it contacts the cap center contact. probably due to the destruction of the center contact.
4. Points looked good and I had 30 deg dwell.
5. Spark was strong but not consistent ( what you would expect from an electrical misfire)
6. Accelerator pump shot fuel into the carb
7. No gushing of fuel into the carb at idle or off idle
8. 12 V to the ballast resistor.
9. 6-8 volts at the coil while running
10. Ignition timing was right where it was supposed to be.
11. tried advancing and retarding, no improvement
Off to the parts store...
Bought cap, rotor, coil. Replaced the parts and no improvement.
Being 50 miles from home and having limited tools and time I had the Dart towed home $$$.
Today I started doing more investigation.
1. checked ballast resistor. functioned correctly
2. opened carb, everything looked and functioned good
3. disconnected the coil capacitor, no improvement
4. disconnected the condenser, no improvement but I did notice the lead wire from the coil to the points felt odd.
5. replaced the lead wire, no improvement.
6. replaced the capacitor and condenser and of course dropped a nut into the dist!!!
7. pulled the dist to retrieve the nut.
I found the dist shaft had end play up and down. seemed excessive but I had nothing to compare it to so I assumed it was normal. I noticed that the inside of the dist had metal or other dust / fragments in the bottom, and a circle where it looked like the bottom of the plate that holds the centrifugal weights and springs might have been ribbing. I cleaned it out and reassembled and lubed the dist and put it back into the engine.
Still major misfire.
I started investigating how much end play is too much when I remembered that my dad had kept the original dist (not sure why he replaced it with the one in the engine now) so I pulled it out to see if it had end play. Barely any... maybe a few thousandths I thought what the heck and swapped it in (the old dist has sat in a box, points in place for 30 years and and it had 264,000 miles on it when it was removed in 1987)
turned key.... Fired right up. No misfire, no stumble, no issues.
I oiled the side oil port cap and took it for a spin. The dwell was 29 doesn't get better than that.
I looked at the old dist. it had 86 thousandths of play. My guess is that the shaft was moving up and down enough for the rotor to no longer make contact with the cap contact and throughing spark all over the place.
so why is this the tale of the $350.00 distributor....
Rotor, cap, coil, dwell tach meter ~ $50.00
Tow 50 miles on a flatbed ~$300.00
Replacement dist- Free
So the moral of the story.... Keep a spare Dist, 1/2 inch box wrench, 5/16 ignition wrench in the trunk. save your self $350.00!
Enjoy!
