Distributor wiring
- Thread starter old31
- Start date
BRENT in 10-uh-C
Well-known member
If you want to change the distributor on the side of the road, what do you do then? Unscrew it from the base plate? Imagine the stress that would cause if you dropped that little nut into the grass or gravel while working on the side of the road.
I honestly don't see the rationale of this tip on a properly restored Model-A. The only time the lower plate ever creates a problem is when the wire end comes loose causing an intermittent connection. Although there is an aftermarket piece to replace the wire, -even this is not needed if the original wire is replace, -or if the wire ends are recrimped and resoldered.
These Tech Tips are often written as a (harder) way to band-aid the original problem. But with that said, maybe next month's Tech Tip will be to purchase a membership to AAA and then remove the spare tire and jack from your Model-A. If you ever have a flat, let AAA bring you home where you can change it in your driveway.
Fhane
Senior Member
What is the problem with the original set up? Also the plate spring is eliminated. Without the spring the upper plate will vibrate.
For over 60 years I have worked on many Model A’s. One of my pet peeves is all of the home made fixes, custom wiring, short cut repairs and so forth. The customer brings the car to the shop for a repair. Now is it my job to figure out the custom repair someone else made? Absolutely not. I explain to the customer the repair will be done as close to the original standard or I will not do the job. Sometimes an exception is made, but not often.
The Model A is probably the most documented automobiles in the world. We buy an antique, I believe we should keep it that way, allowing for modern safety applications.
For over 60 years I have worked on many Model A’s. One of my pet peeves is all of the home made fixes, custom wiring, short cut repairs and so forth. The customer brings the car to the shop for a repair. Now is it my job to figure out the custom repair someone else made? Absolutely not. I explain to the customer the repair will be done as close to the original standard or I will not do the job. Sometimes an exception is made, but not often.
The Model A is probably the most documented automobiles in the world. We buy an antique, I believe we should keep it that way, allowing for modern safety applications.
The Master Cylinder
Well-known member
It looks like this tip is more geared for when you use the modern upper plate as it has the condenser on the upper plate.
nkaminar
Well-known member
The original configuration was made to discourage theft. The distributor had to pulled from the engine to unscrew the armored cable. Without the pop-out ignition switch popped out the wire to the distributor was grounded. This made if very difficult to hot wire.
Fhane, post #6, had a good point. Without the spring for the top plate there would be a lot of vibration there, which could effect the grounding of the fixed point.
With the stock condensor and points, this "fix" would not work.
Fhane, post #6, had a good point. Without the spring for the top plate there would be a lot of vibration there, which could effect the grounding of the fixed point.
With the stock condensor and points, this "fix" would not work.
CWPASADENA
Well-known member
Jim/GA
Well-known member
The spring between the upper and lower plate is also the primary source of ground for the upper plate. The distributor body was (or is) coated with paint, and the upper plate fingers in the slot don't make a very good ground.
Will N
Well-known member
The only issue with the lower plate is the pigtail connector that flexes as the upper plate moves with the spark advance. Over many years, the insulation can break and the pigtail can short out against the body of the distributor. This so called fix does not change the underlying issue. That wire from the armored cable direct to the points can chafe as the upper plate is moved too.
The best repair IMO is to use this fine strand silicone wire to replace the wire on the lower plate - much more flexible and forgiving. I've used this wire with great success.
https://www.amazon.com/gp/product/B017TFR6SM/?tag=atomicindus08-20
https://www.amazon.com/gp/product/B017TFR6SM/?tag=atomicindus08-20
Bob Bidonde
Well-known member
The ignition points, the condenser and distributor casting need to have a low resistance ground path back to the battery. The slide shows how to check the ground path. Note the check is to the battery, so the resistance of everything in between is measured.
Attachments
Thanks for the graphic, Mr. Bidonde. When I first saw this in the past, I soon checked the resistance on our coupe's engine ignition ground path. I probed the ground side of the points and the positive battery post as you describe. As I recall, the resistance was a fraction of an ohm and a small one at that.
Our motor was a fresh overhaul 3.5 years ago. I've had the distributor out 3 times since then. When I do, I use some 320 wet dry sandpaper to clean and lightly scuff the boss around the base of the distributor and the small one around the locating dowel pin, even the lower part of the casting that drops into the head. I do the outer surface of the hole in the head too.
I smear a shadow, not a coating, just a shadow of conductive / carbonized grease on these surfaces to retard any formation of corrosion. The ground and cable connections at the frame and battery get the same. Haven't had any ground issues yet.
Our motor was a fresh overhaul 3.5 years ago. I've had the distributor out 3 times since then. When I do, I use some 320 wet dry sandpaper to clean and lightly scuff the boss around the base of the distributor and the small one around the locating dowel pin, even the lower part of the casting that drops into the head. I do the outer surface of the hole in the head too.
I smear a shadow, not a coating, just a shadow of conductive / carbonized grease on these surfaces to retard any formation of corrosion. The ground and cable connections at the frame and battery get the same. Haven't had any ground issues yet.