Worn contacts in cap

[green 66]

Hi guys! Was tuning up my 66 with cap and rotor and noticed contact points inside cap were only worn on outside edge.Seems like rotor is barely making contact.What would cause this.Motor is a 73 440 electronic 6a msd.

 

[khryslerkid]

The rotor doesn't make contact with the "posts" inside of the cap. An arc jumps between the rotor and the cap when they get close enough to each other. The arc creates pitting and carbon buildup on the leading edge of both contacts, rotor and cap. When there is too much carbon, pitting, buildup, it compromises the amount of voltage that goes to the spark plug. Time to clean or replace. Capiche?

 

[green 66]

Replace cap and rotor or plugs.It seems like the arc is catching the tail end of the contact. It's a fairly new cap

 

[khryslerkid]

How bad do they look? If they look bad, replace...

 

[khryslerkid]

Replace cap and rotor or plugs.It seems like the arc is catching the tail end of the contact. It's a fairly new cap

Counterclockwise rotor rotation on the BB distributor.

 

[PurpleBeeper]

A long time ago when my motor still had points I got actual PHYSICAL contact between the rotor and the contacts inside the cap. The cap contacts looked "scraped". My problem was distributor housing bushing wear which allowed the distributor shaft to wobble.

 

[khryslerkid]

check that too! Thanks PB

 

[kiwigtx]

Hi guys! Was tuning up my 66 with cap and rotor and noticed contact points inside cap were only worn on outside edge.Seems like rotor is barely making contact.What would cause this.Motor is a 73 440 electronic 6a msd.

Please consider carefully in future where you post the questions...this was originally in the Welcome Wagon.

 

[Mopars & Missiles]

Replace cap and rotor or plugs.It seems like the arc is catching the tail end of the contact. It's a fairly new cap

Possible the rotor phasing is late.

 

[green 66]

How can I fix that

 

[hangn0ut]

What distributor? The phasing is set at the factory. Its designed in and very hard to change or mess up. MSD does have some adjustable rotors. Dont think you have that though. You might drill a hole between #1 post and the coil post and then check phasing using a timing light looking through the hole. You will be able to see if it lines up properly. Check it at higher rpm also.

 

[green 66]

Thanks Hangnout-if it is not lined up than what.The dist is electronic probably 1974? Cap and rotor are accel#8320.will try to get some pics.

 

[hangn0ut]

Factory distributor,get a factory cap and rotor.your better caps have raised half circles of plastic around each terminal inside the cap. To help prevent carbon tracking. I think mallory caps are made like that. Remember when you check phasing your rotor should sweep across the terminal as the timing advances.

 

[hangn0ut]

Replace cap and rotor or plugs.It seems like the arc is catching the tail end of the contact. It's a fairly new cap

Yeah,here your phase is fine. Most of your run time is at low rpm. As rpm comes up and timing advances the rotor sweeps to the other side of the terminal. You will see this if you check it with a timing light.

 

[green 66]

Ok thanks-will get factory cap tomorrow