Distributor pushing up hard on rotor?

[Cudakiller70]

340 had a miss, pulled the cap. Some carbon dust on rotor and also there's a dent in the rotor top.  Also in the cap a piece of carbon is broken off the center post. Can the distributor be pushing up that hard?

[73_Cuda_4_Me]

Unless your roll pin holding shaft collar at bottom of distributor housing is sheared, the shaft can't move 'up'... should only have about .008-.010" end play maximum...

 

[Cudakiller70]

Unless your roll pin holding shaft collar at bottom of distributor housing is sheared, the shaft can't move 'up'... should only have about .008-.010" end play maximum...

 

Just checked, it has .030 clearance. Looks like I need to order some shims.
Do you think the tolerance up top is that tight that .020 could make a dent in rotor? 
The upper shaft will move up and down about an 1/8" also.
Also theirs no marks or ID on this distributor, guessing by pictures it's a profom or knock off.

[73_Cuda_4_Me]

The upper shaft movement sounds a bit much... the .020 isn't too bad... I probably have that much or more in my stock dizzy...

There should be more than 1/8" clearance from rotor to cap.... the graphite button usually sticks out that much when your looking at bottom of it..  not sure of how the mark got there.. maybe some play-dough in cap and slip together to see what clearance you have?

[Cudakiller70]

The upper shaft movement sounds a bit much... the .020 isn't too bad... I probably have that much or more in my stock dizzy...

There should be more than 1/8" clearance from rotor to cap.... the graphite button usually sticks out that much when your looking at bottom of it..  not sure of how the mark got there.. maybe some play-dough in cap and slip together to see what clearance you have?

OK did Play-do using no pressure putting the cap on there is a gap between the metal tang and the top of the rotor, but when I push down on the distributor on the bench to simulate the shaft going up all the Play-do was squeezed out so ya maybe .020 is enough to do that?

[AARuFAST]

If you are using that blue cap it is not for electronic ignition dist.
Should be tan, rotor should be for electronic dist. Yes there are two different caps and rotors
Looks like the cam on dist shaft is black? ? ? 
Rotor looks like it was not pushed down enough on shaft.  Could be wrong rotor to eat up the cap and carbon button.

[73_Cuda_4_Me]

Wow... wouldn't expect .020 to make that much change... I'll see if I can give you a clearance value for mine... can't get it this afternoon, though...

Supplier variation could be biggest culprit... I'd get a different cap/rotor combo from another company... I don't recognize the 'Standard' company on the box in your picture...

I'll also see if I can get measurement from rotor tip to dizzy housing, just so you know how high mine sits, and then one from mounting lip of cap to one of the plug towers inside...

[AARuFAST]

Can u show photo of the eight contacts inside of distributor cap. Where is the rotor hitting on the contacts............

[Cudakiller70]

If you are using that blue cap it is not for electronic ignition dist.
Should be tan, rotor should be for electronic dist. Yes there are two different caps and rotors
Looks like the cam on dist shaft is black? ? ? 
Rotor looks like it was not pushed down enough on shaft.  Could be wrong rotor to eat up the cap and carbon button.

Cap & rotor
Ahh... I did tell the parts guy it is electronic. The blue cap (blue streak) I thought was a better part, the first cap they brought out was black, but I didn't like that it had aluminum inserts. Ok will go back Monday their closed today.
Yes cam is black.
Yup I'm hoping it's just a mis matched cap & rotor, but looking into it I will need to shim the shaft.

[73_Cuda_4_Me]

No rush on shimming... mine has been running at least .020 (more, actually) since I got the car back in '04... haven't had to bring it to spec yet, and no problems...

[Cudakiller70]

Can u show photo of the eight contacts inside of distributor cap. Where is the rotor hitting on the contacts............

I don't see any contact on the 8 posts only the chip on the center.

[Chryco Psycho]

If the cap is rocked a little as it is installed it can chip the carbon center or if the rotor tab is offcenter it can ride on the edge shaving the center post down

[Cudakiller70]

If the cap is rocked a little as it is installed it can chip the carbon center or if the rotor tab is offcenter it can ride on the edge shaving the center post down

That makes sense for center post carbon.

 Any thoughts on the tab pushing into rotor top?

[Chryco Psycho]

AT least the black cap has brass contacts !
 under the foam in the top of the center shaft there is a small snap ring that holds the upper shaft onto the lower shaft , if that snap ring in not seated or even there the upper shaft can float too high upwards so make sure it is in there , obviously you have a lack of clearance so it could be anywhere from the body being machined too low or the shaft being too long or the cap miscast to short or the center button position too low or ....

[YellowThumper]

I would also confirm that the rotor is 1 not too loose and 2 not too tight preventing it from fully seating on dizzy shaft.