Burnt Rotor ( AC Delco)
 

96 Astro distributor rotor has burnt to ground twice within a couple or three months. Has anyone seen this and or know of a common cause? I've never seen one do this before, and both were practically identical. I've had it since new, 150k. Runs great, no sign of anything going wrong until it actually fires to ground on the rotor mounting plate / distributor shaft, shutting it down. No codes. Ideas?

Welcome to the forum

make sure the cap is seated snuggly, may want to consider changing the coil...

Thank's for responding. I'll be sure to check the fit again. Ironically the first cap and rotor change wasn't until about 110k and they looked fine. I should have left them alone, but along with changing the plugs (recommended @ 100k ) which also looked great, I had the parts so put everything on fresh: plugs, wires, cap and rotor (all Delco), trying to keep the doghouse R&Rs to a minimum. Toothbrush around the base @ cap install. Coil tested within factory spec'd ohm ranges, although those were cold checks. This weekend I'll check it at running temps, now feel dumb for forgetting it then. I'll let you know.........