Burnt Points?

I had trouble with a Shovel-head Harley burning the points, while purchasing a third set, I ran into a rep from Blue-Point. He had a look and pointed out the condenser did not match the points, not even close. He gave me, (get this) a new set of points and a matched condenser, and I never had trouble with it again. The old set would melt and pit one side of the points (I believe the contact on the point arm) and just tarnish the other side. I wonder how many condensers out there actually meet the requirements of the point sets we are buying?
 
Farrell - Good question on matched points/condenser. I am wondering if anyone has a method for matching points to condensers. Is there a formula or chart that a person could use?

Anyone out there know the answer?
Thanks,
 
they get dark grey ish like ash, then pitted on one side. some times you can clean them with what i like to call a fingernail file. just a strait file that is no more than about .025 in thickness, they really work great. Im not one to just throw out $20 points, so if they look burnt, i make sure they are gapped correctly if they are, and the car was missing or running bad, i put in the new set and hold on to the old just incase that wasnt the problem. If they arent gapped correctly, but appear to be burnt, i gap them and see what happens. Most the time they work...for a little while longer.

the biggest cause of burnt points i have seen, is people putting to much dang oil down either the new cam bolts with the center oiler, or down the original oiler on the side. I was fixing a guys car one time and there was oil all inside the distributor. Underneath the condinser, under the rotor, splashing on the sides of the body, and of course in the points. When i asked him how many drops he put, he said I dont know a few lol. So after taking everything apart and cleaning everything, with a mop lol, we threw in a new set of points and it ran perfectly. (pointes were burnt badly, and had not just a pit on one side, but put a crater in it lol) he just couldnt beleive them $20 mustang points would burn up so fastly, i mean he had just put them in right befor the tour, when he "fixed everything else"
 
Perhaps a bit of additional info would help. I'm running a friends engine and distributor while my engine is being rebuilt.

The dist needed new points and has run fine for the last 500 miles or so. They were regapped to account for point block wear. Yesterday, after a 3 minute stop for gas, the vehicle started backfiring, bucking and I barely made it the two blocks home.

Inspection revealed that the points were not closing properly due to extra metal on one side of the point arm contact. It almost looked like a very small teardrop piece of solder on part of the contact. I might add that no soldering has been going on anywhere near the distributor, or anywhere else. No pitting was visible. I removed the point arm and filed the contact flat so that it now closes properly and the car has run fine for the last fifty miles or so.

However, something caused this to happen, and of course if it happened once, it will happen again (probably miles from home on a deserted road, at night, with no help around). lol

That's why I pose the question; has anyone seen this particular symptom before? :confused:
 
Inspection revealed that the points were not closing properly due to extra metal on one side of the point arm contact. It almost looked like a very small teardrop piece of solder on part of the contact. I might add that no soldering has been going on anywhere near the distributor, or anywhere else. No pitting was visible. I removed the point arm and filed the contact flat so that it now closes properly and the car has run fine for the last fifty miles or so.

Ive had bundles of dist. problems before, but nothing quite like you are explaining, but the picture in my head is probably wrong. Are you using the modern points, or originals? i imagine it would make a difference in your case but im just trying to process in my head what could be going on inside there to make a teardrop shape of excess matter of some kind. I would just carry an extra set of points with you in you trunk just in case it happens again. Some oil or dirt probably just got inside the contacts and burnt leaving some kind of build up on the contact points. Without seeing them infront of my face, its hard to picture what you are describing.
 
if the points are dark blue or black they are considered burnt. at this stage the coloring becomes a insulator. metal transfer is caused buy a condenser that has too much or too little capacity. depending on which side of the points the buildup is indicates if the condenser is over or under capacity. been too long ago dont remember which is which. scotty
 
Do not know how points are matched to condensor except for Current carrying capacity of the points as coil and condensor form an LC (Inductance-Capacitance) tank circuit. Think the condensor is about 20mfd, but do not know what the inductance of the coil which is in Henry's but the coil and the condensor form a resonate circuit at some frequency. The points only make or break the connection through the coil for current to flow and the condensor is across this connection. When you have current flowing through the coil and break the flow of electrons the magnetic field in the coil collapses instanteously creating the high voltage in the secondary winding of the coil attached to the plugs via the distributor. There is a lot of current flowing across the points when you break that circuit which is why they burn and if the points cannot carry that amount of current they disintegrate more quickly. That is one reason that in 70's car makers went to Capacitive discharge ignition systems and points lasted forever except for rubbing block wear. The current through the points went to milliamps instead of many amps.
 
Logan said:
Some oil or dirt probably just got inside the contacts and burnt leaving some kind of build up on the contact points. Without seeing them infront of my face, its hard to picture what you are describing.
Click to expand...

Appreciate the responses. I understand how difficult it is to picture. I now wish I would have attempted a photograph.

The "buildup" was definately metal (like solder), and was distinctly lighter in color than the actual grey color of the contact. It took awhile to file it off.
 
One thing you didn't mention was whether this monster was running on 6v or 12v.. Like Scotty said build-up is condenser over or under capacity, but, matching condensers is unheard of today.. Today you just buy the condenser listed in the book for the application.. Oh almost forgot, white is heat/arcing, blue/black is real hot..
 
Thanks for the reminder Patrick.

Running original dist, original style points, 6v. The "build up" appeared white near the edge of contact leaving about .018" gap on the other side of the contact points when closed. So the points were not aligned parallel. Never seen anything like it before.

Since I last posted, I did the shop test on condensor and have good spark from the high tension wire.
 
HoarseWhisperer said:
Thanks for the reminder Patrick.

Running original dist, original style points, 6v. The "build up" appeared white near the edge of contact leaving about .018" gap on the other side of the contact points when closed. So the points were not aligned parallel. Never seen anything like it before.

Since I last posted, I did the shop test on condensor and have good spark from the high tension wire.
Click to expand...
My thought is, being as you are running original points, that rules out the possibility of a wrong condenser. I have been running the same set of original points in one of my cars for 10 years. I had a set of original points to burn out in my 30 standard roadster after only 3 years . I believe that the problem was caused by one of those disconect switches that connect to the battery cable end. The cable had some corrosion and was not tight enough. I think that it caused a voltage spike and burned out the points.
 
Thanks for the tip Purdy.

After reading, I checked out the cable and disconnect. Everything seems in order, so it helps to rule that part out.

Perhaps it would be prudent to shop test the coil?
 
OK, I guess a couple questions.. Well, a statement and a question.. It used to be fairly common on 'modern' style points to have to adjust/bend/warp them to set parallel.. Did you do anything to your condenser?? Is it a re-pro?? I've found either of the mounting screws loose before, even though most of the time they are too tight/rusted/frozen to remove..I guess it was a couple questions after all..
 
You must log in or register to reply here.
Back
Top