Holley Distributor cap & rotor wear

[Chris]

What do you think of the wear on this distributor cap? It has about 400 miles on it and the rotor, and this is the second time it has turned out like this. To me it appears the rotor is shorter then it should be. Holley distributor with Standard brand cap and rotor. I did some measurements to try and conclude what I was thinking. I have a new Standard brand on the bench that measures the same and guess the one before was very close as well. I have ordered new Airtex/Wells brand to see if they are different. I am having EMI (interference) issues with my FI system and think this may be the source. Let me know what you think or reccomend. Thanks

196 ci IC
Hamilton Fuel injection
Holley Distributor with Duraspark conversion
Standard IH1443 cap (made in USA)
Standard IH318 rotor (hencho in mexico)

 

[int77345]

are those terminals broken in the dist cap ?
is the rotor impacting them ? rotor should not touch them

 

[Chris]

The posts are machined in half. No contact with them at all. It doesn't appear that the rotor is damaged from contact either. It seems to me the rotor could be longer where it would pass over the machined area of the post, instead it is passing just short of the "contact" area by my measurements. Speculating that the arc is possibly damaging the cap do to jumping to the contact? Just not sure why this is happening for a 3rd time in very few miles. Looking for any insight. Doesn't look normal to me. Thanks

 

[Chris]

Additionally, rotor height measurement compared to cap height places the rotor just below machined "contact" area of post on cap. So that part seems correct.

 

[Scoutboy74]

Arcing usually leaves black carbon deposits on the cap contact surface. That damage looks like physical contact. Is the rotor down all the way on the shaft? It appears as either the rotor is sitting up too high, or the cap is too far down on the distributor body, although I don't know how that would be possible. Can you post some pics of your distributor while the cap is off?

 

[Chris]

The top of the rotor to the housing is 1.466 inches.
The cap is 1.465 inches from mating surface to the "contact". So it's right there. The top of the rotor appears dirty so that could be it. Shouldn't the tip of the rotor pass over the contact area? My sketch photo shows the rotor is too short to do so. You may be right though, the rotor may be hitting the cap by the above measurements. What's the cure? Hoping the Airtex/wells cap and rotor a slightly different. They won't be here until Friday.

 

[1975IH200]

Are you using the correct dust cover?

 

[Chris]

No, I do not have the dust cover installed. It will not fit with the duraspark parts installed. That would give it a liitle boost though wouldn't it? Wonder if i could cut one up and make it fit.