ignition issue prevention?

[alex 18]

I had the starter solenoid fail on my car, which in turn, damaged the Mallory coil and possibly the Mallory module. Are there any modifications I can implement that would prevent this in the future? Eliminate the starter solenoid?

[det0326 179]

I had the starter solenoid fail on my car, which in turn, damaged the Mallory coil and possibly the Mallory module. Are there any modifications I can implement that would prevent this in the future? Eliminate the starter solenoid?

 

I don't understand how this could happen. If this is original wiring harness

the ignition system only receives 12 volts from solenoid while cranking. Did the solenoid hang up or something. Maybe more info would explain it.

[alex 18]

Yes, the solenoid did get stuck closed. I replaced the solenoid but the damage was done. I am trying to avoid this situation again.

[Brian Conway 264]

Had the same experience a couple of times in the last few decades. Fortunately it happens, to me, so infrequently that I just take my lumps, fix, repair, replace and move on. The only fix I know of is; get out of the car quicker and smack that thing. Brian

[magician 13]

How does a stuck relay damage a coil ? I'm not familiar with the Mallory set up. I might have a solution if the theory of operation is explained. I assume the resister wire is not a factor.

[alex 18]

The Mallory setup is no different than the OEM. An external coil and a distributor. When the starter solenoid is stuck, it sends 12 volts directly to the coil. The coil cannot handle 12 volts for too long. In my case, I only understood the ill effects of a faulty starter solenoid after I began troubleshooting the ignition issues.

 

A caveat, I have not yet replaced these parts as I would like to avoid a repeat performance. So, at this point my theory of what is broken and why it was damaged is not proven. However, as I mentioned, I do want to avoid this situation and am looking for advise.

[harlan69mach 21]

The purpose of the starter relay is to provide current to the starter when the ignition is turned to start. The coil will receive 12 volts when the ignition is in both the start position and the run position. The coil must have 12 volts when the engine is running to provide the high voltage to the distriutor/spark plugs. Leaving the ignition in the run position with the engine not running for an extended time could damage the points and maybe the coil.

If the starter relay stuck the starter should be spinning and alert you that action is needed.

[det0326 179]

The Mallory setup is no different than the OEM. An external coil and a distributor. When the starter solenoid is stuck, it sends 12 volts directly to the coil. The coil cannot handle 12 volts for too long. In my case, I only understood the ill effects of a faulty starter solenoid after I began troubleshooting the ignition issues.

 

A caveat, I have not yet replaced these parts as I would like to avoid a repeat performance. So, at this point my theory of what is broken and why it was damaged is not proven. However, as I mentioned, I do want to avoid this situation and am looking for advise.

 

As Magician said I don't understand why this would happen either, I too am not familiar with the Mallory coil but I know that the older OEM coils would take a lot of abuse before burning out. I don't know how much current the Mallory can handle though. Anyway for protection though you can do a lot of things in designing circuits for that purpose but I think the cheapest

thing to do is put another solenoid to energize at the same time to handle the 12 volt circuit going to the coil. You could even use a relay as long as it will handle the current going to the coil. If you want to explore this idea

let me know and I will try to explain it farther.

Dave

[alex 18]

Thanks for the responses.

 

Bob, the OEM ignition wiring does provide, to the coil, 12V while starting but less then that while running due to the resistance wire from the ignition switch.

 

Dave, I am surprised as well that the coil appears to be non-functional. I would have thought that the module or ignition switch would have been damaged. However, according to Mallory, the coil should have an internal resistance of 0.6 ohms while mine has 0.1-0.2 ohms. I would be interested in your ideas for hardening the ignition system. Would a mini-starter with an internal solenoid be beneficial? Presumably, this would require a relay to provide 12V to the coil while starting.

[stangs-R-me 121]

Low battery voltage can sometime cause the starter solenoid to stick.

 

If you drive car everyday and your charging system, wiring, and battery are performing like new you should not have this problem.

 

If your car is a weekender or maybe even less often, you probably should keep a trickle charger (Battery Tender or similar) hooked up to it and battery will always be at 100% when you decide to take it out on a weekend.

 

My car is probably a once or twice a week over the Summer but there are times where I don't get in it for 3 or 4 weeks.

 

I bought a Battery Tender 10 years ago or so and keep it hooked up to battery all winter and "most" of the Summer ... I say "most" because sometimes I'll forget to hook it back up after a drive. Anyway, I have not had battery or solenoid problems since.

 

I've also got a Mallory (Unilite) Distributor and Coil running through the stock factory wiring.

 

Doug

[magician 13]

Get a 30 amp Bosch relay

Battery power to pin 87

Ground pin 86

Tap off start wire on solenoid to pin 85 on Bosch

Pull "I" wire off solenoid and hook to pin 30 on Bosch

 

No change in operation ,just takes coil 12v out of solenoid

[det0326 179]

Thanks for the responses.

 

Bob, the OEM ignition wiring does provide, to the coil, 12V while starting but less then that while running due to the resistance wire from the ignition switch.

 

Dave, I am surprised as well that the coil appears to be non-functional. I would have thought that the module or ignition switch would have been damaged. However, according to Mallory, the coil should have an internal resistance of 0.6 ohms while mine has 0.1-0.2 ohms. I would be interested in your ideas for hardening the ignition system. Would a mini-starter with an internal solenoid be beneficial? Presumably, this would require a relay to provide 12V to the coil while starting.

 

Alex

Are you sure your meter is accurate?

I would check like a .5 ohm resistor and see how your meter reads it.

you are only talking about .4 ohms or so and I know some of the cheaper meters aren't that accurate when measuring a few tenths of an ohm. Sometimes you can make the reading change a few tenths of an ohm by how tight you hold the leads to the terminals. You may have an expensive, nice multi meter I don't know but I would still check a known resistance with it before I trashed the coil.

Dave

 

BTW forgot to mention the starter, Installing a mini starter would be up to you, I don't see that it would be of any benefit other than there could be a problem with your original starter causing it to draw excessive current and damaging your solenoid. You might could just change the starter an solve all your problems.

Edited December 19, 2013 by det0326

[alex 18]

I did check with two different multimeters which both read 0.1-0.2 ohms. I will check with a few resistors I have tomorrow. I have what I would consider a decent multimeter...craftsman.

 

Magician, thanks for the instructions.