1972 dart - stopped running while at 50 mph ? no warning

-
There used to be a longer rotor, which is no longer available. I doubt very much that is causing your problem per se. The rotor MIGHT BE

...Defective, AKA manufactured wrong, which would be rare
...Have carbon track "punch through" under the contact and down into the female area for the shaft. I already told you to check that maybe you missed it. Examine it carefully or replace.
...Be certain you don't have a wrong part somehow
 
...Have carbon track "punch through" under the contact and down into the female area for the shaft. I already told you to check that maybe you missed it. Examine it carefully or replace.

i saw that , i just was not sure what to look for . but YES , i think there is what you describe " punch through " what is that from ? what causes that ? i replaced it , but want to know the cause , so maybe i can help prevent that from happening again . thanks
 
Punch through can be from several things including say, a crack , void or defect in the rotor. This primarily happens with high energy ignition systems. Another cause is ANYTHING which causes a high voltage condition in the secondary circuit, meaning the path from coil--wire--cap---rotor--to the plus towers---plug wires---to plugs--to cylinders

Bad wire, broken plug, disconnected wire, burned valve or other lean/ misfire condition. This causes an overvoltage condition, and the spark voltage skyrockets--and just like lightning---looks for the easiest path to ground. If the rotor is somehow compromised, material quality, humidity, dirt, etc, it can arc across/ carbon track or punch through
 
points checked ( post #55 ) and are fine . engine still in time and not jumped , as below

with good coil hotwired , and swapped out condenser with and old one still did not start . dwell then checked and reset to its happy place at 34 . no start . rechecked spark with tester . sparking good from coil , kinda weak at spark plug wire . then i pulled out of the trunk an old , kinda funky rotor with bent up tab and all . however , i noticed it looked slightly bigger than the 3 months old one that was in the car . i mocked up with an old cap that came off the car from the last tune up and the new rotor could barely reach the contacts ( not exact science here , just holding it in the cap loose ) but then checked the old rotor and it was way close up to the contacts . anyway , put old funky rotor in and it started right up with the number 1 spark wire still attached to the spark tester ( I.E. ran on 7 cylinders ) . i shut it down then . connected the coil positive wires , the number one spark plug wire , and the air cleaner etc . started up great and ran for a half a minute , before i cut it off because i heard what i think is a valve tap . i guess its possible the rotor i recently got was wrong and was just long enough to last a few months , or it failed or something made it fail .

my question now is the valve tap , now i know its been sitting for a week being cranked , so i get there might not be much oil in there up top . plus its really cold out . was only running one minute . the points adjustment should now have changed the timing a little . timing showed just a hair or two after 0 . cold engine at idle ( not fast idle ) . i think i usually have it at 2.5 ( with engine hot ) , but cannot remember if that was before or after 0 . i wrote it down somewhere , but finding that will take another week . the plan now is to get a new rotor ( or two ) , and while at it a condenser , another coil , cap wires points , just to have extras . then with a new rotor etc . warm it up and set the timing . that might take care of the valve tap , but how concerned should i be running it like that for timing it etc ? its not a horrible tap , but i know its not good to hear it at all . i think its just one cylinder , but will check all by the hose/ear method if it doesn't go away quickly after warmup/timing . any suggestions before or after setting the timing ? thanks again everyone . i appreciate everything .
I see nothing about where you verified timing is right. Can you elaborate? Just because the points are "good" means nothing.....except the points are good.
 
I see nothing about where you verified timing is right. Can you elaborate? Just because the points are "good" means nothing.....except the points are good.

the timing showed just a hair or two after 0 . cold engine at idle ( not fast idle ) . timing is a little bit off from where it was , i just can't remember exactly where i set it previously . wrote it down somewhere , probably can't find that . but i can adjust the timing again . i wrote still in time , only because it was running really good . i hastily assumed that it did not jump or break . i still have not verified it with the test you mentioned yet . me mentioning the points are fine was just a follow up to two other members posts , who wanted me to check them after i accidentally went battery positive to coil negative . they did not get burned from that mishap .
 
the timing showed just a hair or two after 0 . cold engine at idle ( not fast idle ) . timing is a little bit off from where it was , i just can't remember exactly where i set it previously . wrote it down somewhere , probably can't find that . but i can adjust the timing again . i wrote still in time , only because it was running really good . i hastily assumed that it did not jump or break . i still have not verified it with the test you mentioned yet . me mentioning the points are fine was just a follow up to two other members posts , who wanted me to check them after i accidentally went battery positive to coil negative . they did not get burned from that mishap .
I didn't think it was running now?
 
yes , running really good . replacing the rotor got it running . the rotor had punch through , i just found out from 67dart273 what that is and what to look for . i didn't see it until really closely examining exactly where to look . i still have to fine tune the timing . and trying to figure out what caused the punch through . but , at least its running and driving .
 
GREAT!! Rotor failure would be rare on non-electronic ignition. I recommend you check all plug wires and plugs, maybe do a compression check and be sure all 6 are "hitting."
 
-
Back
Top