Burnt ignition points

[Two Crabs]

When I did a complete tune up on my 73 Eldorado I replaced the points, condensor, rotor cap rotor and coil.

The coil was a no resistor required type ( the old coils tags were missing so I took a chance with the resistor style coil )

Now a month later I have a fried set of points.

The NAPA book calls for a "Non resistor " coil which means that there should be a Ballast resistor somewhere down the line.

Any ideas where it might be located as it is not readily apparent. ?

I just found a wiring schematic that shows a resistor wire that is either pink or yellow.
So Ill check for that wire tomorrow.

Don

[The Tassie Devil(le)]

Yes, these vehicles have the resistance wire, and definitely require a "Use with Resistor" coil.

The Starting 12 Volts comes directly from the Starter Motor, and then reverts to the lower voltage whilst running.

As for the burnt-out points, that is another matter.

My memory is fading, but I recall that if the Condenser is faulty, the points burn-out from one side of the points, but I am not sure which side the metal transfer goes.

Bruce.

[Dave Shepherd]

Correct on the condenser, depends on whether it has too much capacitance or too little which way they pit.  But you must have the matching external resisted coil if you still have the resistor wire in place from the ign switch.

[Two Crabs]

I Replaced The Condensor When I Put New points In.

Now It Is Wait And See With The Old Coil.

[TJ Hopland]

My brain is already 'off line' for the day but when I get it going again tomorrow I will try and wrap my brain around the possibility that having too much resistance could cause excessive wear. 

My experience has been that 90+% of the points and condensers available the last 10 years or so are junk on a good day.  I have had lots of issues and even tore apart a few motors thinking it could not have been an ignition problem because they were new.  When motor got rebuilt and still had same problem I narrowed it down to the points being the issue.     FWIW the only brand that has not let me down recently is Standard Ignition. 

I too remember being told you could 'read' the points to tell if the condenser was working and or sized correctly.   I should dig out some of my older manuals and see if any of them can freshen up our memories on these things.  Not sure it would do a lot of good since I suspect many if not all the condensers made today are one size fits all and likely have quite a tolerance window. 

[R Schroeder]

What did you set the point gap at ?
If they were to close they will burn up quickly.
As mentioned above, the condenser is important too.
Roy

[dadscad]

Points should be set at 30° dwell. Acceptable range is 28-32°, 30 being the optimal setting. Check the point plate ground wire, be sure it is intact and hasn't broken with vacuum advance movements. Be sure the distributor point plate has a good ground to the battery negative terminal.

The points and condenser need a good ground to the point plate, the point plate needs a good ground to the distributor body, the distributor body needs a good ground to the block, the block needs a good ground to the body of the car, the body of the car needs a good ground connection to the battery terminal. Give it a check with your digital volt/ohm meter to see what you have.

HTH, David

[Two Crabs]

Thanks For all the replys.
I set the point with my "Sun Dwell meter" at 30 degrees.

I am going to run a 100 or so miles and see what the points look like with the old coil installed.
I am pretty sure that the cause of the burnt points was the resistor coil that I installed last month.

Don

[Two Crabs]

Burnt another set today within five miles of use.

Monday I will replace the "new Condenser" that I recently installed with another new one.

Has anyone installed an HEI system, what brand and any issues ?

Don

[Dave Shepherd]

Sounds like you have 12v to the coil positive side.

[TJ Hopland]

You can install an HEI from a 75-80.   The distributor from a 500, 425, or not EFI 368 will physically fit in the engine.   Where it gets slightly complicated is belt clearance.  The HEI being larger diameter required them to go from the dual AC PS V belt setup to a wider single belt.    If you don't have working AC its not a problem, just get a shorter belt(s) to run to the PS.   Some have reported if getting the distributor timed just right only having slight rubbing.   Others have said they have been running just the outer belt without issues.   If you are getting the distributor from a junkyard also grabbing the pulleys off the donor car will solve the problem too.  Remember the AC pulley also changes so again if you have working AC you have to deal with that too.     

[dplotkin]

Sounds like you have 12v to the coil positive side.

Yup. I suspect your ballast wire is not in the circuit where it limits current (which has the effect of a voltage drop) through the primary side of the coil. An open condensor could cause this symptom too, if it were shorted it wouldn't run. Before you change the condenser verify voltage at coil positive, ignition on, is something below 12 V.

Another thing, the starter solonoid sends full battery current to the coil positive during cranking only-that terminal on the starter should go dead when the key is in "run". See if it is. Full battery current to the coil all the time will burn up the points.

Dan

[n2caddies]

Would this be a good application for the Pertronics electronic ignition set up using the stock distributor?
Randy

[TJ Hopland]

It could be because you then don't have to worry about the belts.   

A few years ago it was much cheaper to just go to a junkyard and grab a used HEI but now days the yards don't tend to be full of these cars anymore and if you do find one they want real money for them.

[The Tassie Devil(le)]

You really need to check the voltage that is going to the coil when the Ignition Switch is turned on.

A Multi Meter is good for this task.   You really have to know what the voltages you are dealing with when trying to solve a problem.

The Positive Side of the coil should be something like 8 volts with the switch on, and when the starter motor is engaged, the voltage should rise to 12 volts, then reverts to the lower voltage when the starter is released.   If it doesn't do this, find out why.

Bruce.

[TJ Hopland]

When you test with the volt meter the points have to be closed.   IF the points are open there won't be enough load to make the resistor really 'show'.   Instead of trying to get the engine to stop with the points closed just running a jumper from ground to the - terminal would do the same thing assuming a - ground system. 

When cranking you won't likely see 12v either, you will see what ever the system voltage is with the starter turning which even with a good battery and stuff will be below 12v.  That's another reason for the bypass circuit on the solenoid, just trying to get as much voltage as possible to the ignition.  Without the bypass circuit you will see an additional drop below system voltage.     

[Two Crabs]

The car has been running now for 1 hour in my shop with no problems.
I changed out the new condenser with another new condenser, cleaned and reset the points.
It appears that the first new condenser was bad. It was one of those cheap sets that "Rock Auto " sells for a $1 or two.

[TJ Hopland]

Sounds like progress.  Hopefully things will start coming together so you can get it on the road soon. 

[Two Crabs]

Ran the car on the "Cleaned" points and another new Condenser. Everything is working ok.

Replaced the cleaned points today with a new set of points that has a condenser built into it, set the dwell to 28 degrees and timed the ignition.

Drive the car thirty miles. Runs just fine now. All the problems experienced since the original tune up were traced to a bad "new Condenser "

Thanks all for your help.

Don

[The Tassie Devil(le)]

Set the Dwell at 30 degrees, and don't forget to set the timing with the Vacuum Advance hose off and plugged.

Bruce.