The magnet on my pickup coil is cracked and crumbling (BB sized pieces of it are coming off all the way around it)... Its been replaced before for the same reason.

My question is, what can cause this and where should I begin my diagnostics?

 

Yes, thats my favorite ignition part. nothing but heat can destroy that. its tuckd away nice neat. if you want to, go through Napa get an ac delco pickup coil. theyre more reliable. i got an autozone pickup coil made in mexico, yee haw. ive had to replace twice in 4 years, yee haw, i guess im feeding Mexico. yee haw

 

Sorry I may have mis identified the component. I am talking about what I recently have learned is called the 'pole peice' its above the pickup coil, spins and has prongs that pass the reluctor, the rotor mounts to the top of this. This is a stock v6 3.1L HEI distributor.

The magnet on this part is eroding in pieces mostly around the prongs.. Just looking at it doesn't make me think of heat damage.. But if i knew, I wouldn't be asking!

 

dude, in my v8 they are combined. i see what your talking about. V8's have one piece. you cant see the pointed metal, but its there sandwichd