Confirm my suspicions: Distributor woes

[GregLast]

So the car died while out on a trip. Never could get it to start again. I figured it was something electrical, because everything else checked out.

Checked for spark, no spark at the plugs.
Checked for spark by removing the coil wire, and holding it next to a head nut, Big blue spark.

Here's where I get adventurous: I took the coil wire out of the distributor cap and held it to the contact on the rotor, and cranked it. Nothing. But, when I held it a little ways away, it would spark to the edges of the rotor contact (on the top of the rotor), and try and start the car. First signs of life.

Is this a bad rotor? It is quite old.

 

[mike657894]

check it for continuity. but also a cheap part and should be part of a tune up. scuff it clean with some sandpaper maybe. you probably need a new condenser. http://www.macsautoparts.com/ford_model_a/model-a-ford-distributor-rotor.html

 

[Smurkey]

Check the carbon "button" in the cap. Sometimes the grind down to nothing and don't make good contact with the rotor.

 

[Fred K-OR]

Do you have a bad distributor cap? Or missing or bad contact under the distributor cap or dose the distributor cap contact not touch the rotor?

 

[Bob C]

Holding the wire away from the rotor increases the gap which increases the output
voltage of the coil, I would be looking at possible fouled plugs.

Bob

 

[dennis lumbert]

If the ignition rotor is bad,the spark will jump thru the rotor to the distributor shaft instead of going to the spark plugs.jumping the spark plug gap in a pressurized cylinder my require more voltage then the rotor insulator can handle if it's cracked or broken down from age.Sometimes you can see evidence of arcing on the inside of the rotor were it sits on the shaft. dennis

 

[Tom Wesenberg]

Yep, I've had to replace a few rotors that shorted through to the shaft.

And because of this you may have wet plugs also.

 

[TinCup]

Greg yes condenser or rotor are possible suspects. Have you pulled the plugs yet? Give us a shout if you can't get any further and I can round up an intervention here in the city.

 

[Mitch//pa]

Shove a little electrical tape up inside the rotor hole to insulate it from the dist shaft.. Then retry your tests

 

[GregLast]

Greg yes condenser or rotor are possible suspects. Have you pulled the plugs yet? Give us a shout if you can't get any further and I can round up an intervention here in the city.

Unplugged the plugs, and they are black, but not wet, and it's not a thick layer. Easily cleanable, and with the car attempting to start, I'm pretty sure once I clean them, they are good.

I really think it could be the distributor cap. I've had my suspicions about the little carbon button on the underside for a while now. I put in an order to Snyders for a new one, and it should be here in a couple days or so. Ordered a rotor as well. I'll check the gap to the distributor body contacts when I get it installed.

Hopefully this breathes life back into her, and I can get it out on the road this next week.

TinCup: If I have any trouble, I'll certainly reach out. I had a change in my schedule at work about the time I started coming to club meetings and haven't been able to make it back out. You guys have a real nice group, and I hope I can join in a little more this year.

 

[GregLast]

Well, that did it! Replaced the distributor cap and rotor, and it's doing much better. Need to redo the carb next, old gaskets, and some OLD seals are creating some inconsistency, I think. Needs to be done either way!

 

[Anteek29]

Great - thanks for letting us know your successful solution