MSD Cap build-up

[Rwillia4]

Thanks for all the input. The buildup is all on the lower edge of the post which makes me thing the rotor is not lined up with post and below it. I'll look up phasing.

thanks again

[RICK LAKE]

Rwillia4 Your cap looks OK. I been through the 1,000 minute cap and less.
This is the best info I have and seen to this date
Center piles fall out of or burnt up in the MSD caps
Burn holes in the rotors
Phazing being out causing all kinds of spark issues
Coils getting weak from heat, vibration, low voltage, and oil filled coils that are mounted on motors in a horizontal location.
For caps and rotors, some of the guys have gone to a cheap cap with a brass center terminal and rotor. It's a SBC I think. If you search CC and FE forumn there are a couple of threads about this with part numbers.
Phazing the distributor, I also have a FAST system with a crank sensor and cam sensor. Need correct phazing to the ECU to know where #1 cylinder is. To get this perfect, get old cap and grind out cap in top with dremel tool and open #1 terminal torward the middle. You want the rotor end to be centered on the cap post and terminal in the cap. You can also run the motor with this open window to check spark and see if you have any other problems. I wouldn't run this on the street because of getting dirt and other debrie in there.
The other thing is which coil are you running?? Are you running a ballast resistor for power. Some coils plug direct to MSD module and some don't.
MSD said "they don't recommend that you mount certain coils on motor or in horizontal location. I think an "E" coil it doesn't matter, oil filled is different. Msd has problems with caps and rotors, I would keep a spare kit along with a spare 6AL in the car with tools to fix on the side of the road. I carry a new distributor, MSD 6al module, and "e" coil with tools. Have used cap and rotor once in 15 years and lent out these parts to another FE owner at SCCA 31.
Good luck Rick L. PS have the remember that there is 20 degrees of steady spark to the terminal at lower rpms. I believe that over 3,000 rpms this is dropped because of rotor speed in the distributor. Also this causes alot of heat in the coil too. Same thing with sequential fuel injection with the old FAST system. Goes from Sequential to batch fire over certain RPM because there is no power differents you will feel.

[STEVE-O]

I replaced mine after about 6K miles and it didnt appear to have as much corrosion as yours is showing there.
A fellow cobra owner gave me the suggestion to seal the front part of the distributor where the wire from the control box enters, with silicon. Lots of dirt and moisture enters thru here. The cap is still vented at the top to release any other buildup of gases.
It may just be that where you are located its more humid and it needs to be changed more often as opposed to here in the dryer NE.