Help! Distributor making noise

[yellowvette]

Boy I'm stuck on this one. My '77 l-48 w/350 trans. has developed a "tapping" kind of noise from within the DISTRIBUTOR itself, I belive it could be "arcing" current, as noise doesn't seem mechanical (by listing with a metal tube), seems to be most noticeable when cold. Worst part is high end performance is not great, low end is fine, will get to red line in low gear fine, but second and third will not exceed about 4200 rpm. New cap, coil, rotor, wires, module, pick up coil (have never replaced capacitor) .Anyone with any insight here, I'm crazy with this, had it apart a dozen times.........
Thanks

 

[LLC5]

Boy I'm stuck on this one. My '77 l-48 w/350 trans. has developed a "tapping" kind of noise from within the DISTRIBUTOR itself, I belive it could be "arcing" current, as noise doesn't seem mechanical (by listing with a metal tube), seems to be most noticeable when cold. Worst part is high end performance is not great, low end is fine, will get to red line in low gear fine, but second and third will not exceed about 4200 rpm. New cap, coil, rotor, wires, module, pick up coil (have never replaced capacitor) .Anyone with any insight here, I'm crazy with this, had it apart a dozen times.........
Thanks

Two things come to mind, 1) missing round rubber insulator between the coil and cap 2) missing ground strap to the coil. It could obviously be another problem, but I have seen these missing many times.

 

[yellowvette]

Thanks, hadn't thought of those, I'll be taking a look tonight.

 

[yellowvette]

Pulled coil out, washer in place, as were ground straps. Checked continuity of all leads, checked out o.k.. Now I pulled distributor out (again), noticed vertical play seems excessive, measures .0695 clearance between thrust washer and gear, seems excessive to me? Could coil be shorting or bad, its only a year old stock replacement, anyway to test coil? Anyone with any thoughts on this would really be welcome, in the meantime it's a good opportunity to clean the motor.........
Thanks

 

[LLC5]

Pulled coil out, washer in place, as were ground straps. Checked continuity of all leads, checked out o.k.. Now I pulled distributor out (again), noticed vertical play seems excessive, measures .0695 clearance between thrust washer and gear, seems excessive to me? Could coil be shorting or bad, its only a year old stock replacement, anyway to test coil? Anyone with any thoughts on this would really be welcome, in the meantime it's a good opportunity to clean the motor.........
Thanks

If the coil is still out, check for carbon tracks between the coil itself and the metal holder surrounding the coil. You should be able to see hot spots on the coil, usually at the corners if there is a problem. Also check the under side of the rotor for the same problems.