Endless point burning

[vtfireman85]

I have worn out the screws changing points on my M, every year I go to dig it out and the points are burned, it goes to bed running ok, comes out not. The battery is always up, suggesting it is not leaking through the switch. I do the works, points, cap, rotor, condenser, today I ordered the full work up, plus a new coil, and an external resistor. The tractor is 12V negative ground. Has a 12v internally resisted coil. 
thoughts? What am I missing? 

[Sparky]

Using a DVOM, check for voltage at the points with the switch off....but if you did have voltage, I'd guess that it wouldn't shut off....

Sooo.......only thing I can really guess is that you have them adjusted incorrectly?

 

Travis

[snoshoe]

What is primary ohm reading on present coil? Any sign of oil vapor inside distributor? Also how do you plan to bypass resistor for starting?

[vtfireman85]

8 minutes ago, snoshoe said:

What is primary ohm reading on present coil? Any sign of oil vapor inside distributor? Also how do you plan to bypass resistor for starting?

I will check tomorrow. At 12V is there a need to bypass? 

[vtfireman85]

12 minutes ago, Sparky said:

Using a DVOM, check for voltage at the points with the switch off....but if you did have voltage, I'd guess that it wouldn't shut off....

Sooo.......only thing I can really guess is that you have them adjusted incorrectly?

 

Travis

.020

[cedar farm]

Points should only be run at 6 volts. 12v for starting and 6v for running.

[vtfireman85]

4 minutes ago, cedar farm said:

Points should only be run at 6 volts. 12v for starting and 6v for running.

Which, theoretically an internally resisted coil should provide, yes? I haven’t checked mine. 

[snoshoe]

2 minutes ago, vtfireman85 said:

I will check tomorrow. At 12V is there a need to bypass? 

If pistons and head are original and it is warm. Probably not. If it has been firecratered or higher compression head put on or it gets cold. Yes. You mention changing condenser each time. You just might want to check one of those out. Leakage and capacitance. 

[vtfireman85]

3 minutes ago, snoshoe said:

If pistons and head are original and it is warm. Probably not. If it has been firecratered or higher compression head put on or it gets cold. Yes. You mention changing condenser each time. You just might want to check one of those out. Leakage and capacitance. 

Fire craters, gasoline head, 22degree dist. 

[snoshoe]

Just now, vtfireman85 said:

Fire craters, gasoline head, 22degree dist. 

You're gonna want a bypass

[vtfireman85]

6 minutes ago, snoshoe said:

You're gonna want a bypass

Any suggestions? It has the full current starter button and a battery ignition 2 terminal switch. Another wire to the points from the starter side of the switch? I assume I want yo put the resistor between the coil and the points, not between the battery and the coil. I have seen both. 

[acem]

I don't like coils with internal resistors.

I prefer standard coil and external resistor.

That way you can check everything and have higher power for starting. 

 

[vtfireman85]

4 minutes ago, vtfireman85 said:

Any suggestions? It has the full current starter button and a battery ignition 2 terminal switch. Another wire to the points from the starter side of the switch? I assume I want yo put the resistor between the coil and the points, not between the battery and the coil. I have seen both. 

Never mind, that wouldn’t work, it would back feed..

[snoshoe]

Resistor goes between ign switch and coil. Bypass goes between resistor and coil. Starter side of switch would feed back. You can add another mometary switch to hold while cranking or use a solenoid like a 450. Can still use present button to activate solenoid. A little overkill but should last.

[HydroTek]

The old discussion about internally resisted coils ...

I have never found a resistor inside any of the coils I have cut open for the copper -- done a plenty of them

There are 6 volt would coils , and 12 volt wound coils
with a few odd balls boasting higher voltage spark that have a different amount of copper

Yeah , I know what is printed on the outside of some coils -- there is no resistor inside

Kinda like headlights -- do you get the internally resisted bulbs to use on a 12 volt system ? -- no you get 12 volt bulbs

You DO use a 6 or 8 volt coil on a 12 volt system with a resistor for better starting
some also use a switch to jump the resistor while the starter is engaged

Burning points is likely because the wrong voltage coil is used -- ya got a 6 volt coil running on 12 volts -- gonna eat points

[vtfireman85]

4 hours ago, HydroTek said:

The old discussion about internally resisted coils ...

I have never found a resistor inside any of the coils I have cut open for the copper -- done a plenty of them

There are 6 volt would coils , and 12 volt wound coils
with a few odd balls boasting higher voltage spark that have a different amount of copper

Yeah , I know what is printed on the outside of some coils -- there is no resistor inside

Kinda like headlights -- do you get the internally resisted bulbs to use on a 12 volt system ? -- no you get 12 volt bulbs

You DO use a 6 or 8 volt coil on a 12 volt system with a resistor for better starting
some also use a switch to jump the resistor while the starter is engaged

Burning points is likely because the wrong voltage coil is used -- ya got a 6 volt coil running on 12 volts -- gonna eat points

12v coil in my case

[Diesel Doctor]

On 10/9/2024 at 8:41 PM, snoshoe said:

What is primary ohm reading on present coil? Any sign of oil vapor inside distributor? Also how do you plan to bypass resistor for starting?

On a 12 volt coil, it should read approximately 3 Ohms when measured between the two small terminals with meter set to Ohms. This coil will not need a resister and should work fine with a 12 volt negative system. The wire from the - side of the coil should go to the distributor. The wire from the switch, 12 volt switched power, then goes directly to the + side of the coil.

On a 6 volt coil, it should read  approximately 1 1/2 Ohms when measured between the two small terminals with meter set to Ohms. This coil will need a resister to work properly on a 12 volt negative system. The wire from the - side of the coil should go to the distributor. The wire from the switch, 12 volt switched power, then goes to the resister first, then a short wire from the other side of the resister to the + side of the coil.

[Sparky]

12 hours ago, vtfireman85 said:

.020

Okay....

You would not believe how many people that "absolutely *know*" that they installed their points correctly have dropped off a tractor at my shop because it won't start.

More than a couple of times I've checked the gap on the points and they were set at .20 instead of .020.....I don't know how they can expect that to work, but whatever.

Then again, I get a lot of people in here that simply cannot make a set of point last a season. Those are simply not adjusted well.

 

Travis

[dieselman]

i have found using a external resistor and adding a second condenser has solved 99% of point burning problems, seems the new condensers don't work as well as the old ones did, usually put the second condenser on the negative side of the coil. this has worked very well for me as making sure the breaker points are aligned properly and clean and adjusted to .020. haven't had the cap off my super m in years, best of luck guys.......dieselman

[HydroTek]

That second condenser was common practice on some of the old Chevy vehicles -- even was a mounting ear on the coil bracket 

Whatever junk metal that is being used for points these days , does not last near as well as the old stock

I always try to steer customers to the Pertronics systems just because of the junk points that are available

[vtfireman85]

1 hour ago, Sparky said:

Okay....

You would not believe how many people that "absolutely *know*" that they installed their points correctly have dropped off a tractor at my shop because it won't start.

More than a couple of times I've checked the gap on the points and they were set at .20 instead of .020.....I don't know how they can expect that to work, but whatever.

Then again, I get a lot of people in here that simply cannot make a set of point last a season. Those are simply not adjusted well.

 

Travis

It’s set at .020, I know the difference. I have had to do a little tweaking before to get points to align, and feel fairly confident I have these correct, but I will take a picture and see what everyone thinks this afternoon. I have a fair number of machines here still using points and this is the only one routinely burning them up. 

[Sparky]

1 hour ago, HydroTek said:

That second condenser was common practice on some of the old Chevy vehicles -- even was a mounting ear on the coil bracket 

Whatever junk metal that is being used for points these days , does not last near as well as the old stock

I always try to steer customers to the Pertronics systems just because of the junk points that are available

I haven't had a damn bit of luck with any of the electronic ignition conversions available.

 

Travis

[vtfireman85]

3 minutes ago, Sparky said:

I haven't had a damn bit of luck with any of the electronic ignition conversions available.

 

Travis

I tried it on a 2N (still 6V) ran like a top, until it got cold, then the cranking pulled the voltage down below its cutout and it wouldn’t pop. You could tow it 6” and it would take right off. 
I am not a fan personally. 

[cedar farm]

When the pertronix kits first came out in the early 1990's(plain white box) you could only get them for GM and Ford. I put one in my 1966 Catalina and it's still in there. I have the uniset points in the trunk but so far haven't needed them. But on tractors I've went back to points. Despite the correct ohms on the coil's and having a full 12 volts to the module, I have found as vtfirman85 said, once warm they ran fine, but cold they were hard starting. Messing with the timing didn't hep. The last one I removed was on my 656 Hydro. It's my loader tractor and a couple winters ago it was near impossible to start. Put the points back in and re-did the resistor wiring and now you barely touch the button and it starts. For points I use Tisco from a local repair shop. Seem to be good quality.

[VacDaddyt]

the points are on the neg side of the coil right?