Copperhead

Pulled the cap off the distributor to change cap & rotor & found THIS.

Haven't looked under a distributor cap for decades but pretty sure this isn't good. The outer ring is loose but doesn't come off. I blew it off (lots of crap flew out) and not sure what to do with it next. Lube it? Clean and lube it? Replace it?

Advice please. No wonder it runs like crap on the top end, cap and rotor are junk too.

Apeiron

What part is loose?

ASE doc

Sounds like the pick up coil cover. I commonly find these loose. It doesn't mean that there is any failure in the distributor. The parts that commonly have trouble are the module that is attatched to the base by two small screws (most auto parts stores will test the module for you at no charge), and the pick up coil that is under the loose cover (this coil can be tested using an ohmmeter, it should read 800-1000 ohms). Also, the pole piece and timing core(the metal "gearlike" peices you see inside the cover) can become dislodged from their mountings and cause inconsistant timing. If your ignition tune is poor(cap & rotor, wires, plugs), that's most likely the cause of your high speed power loss.

If this were my car, I would probably replace the distributor with either a new AC Delco, if you can find one. Or an MSD Pro Billet upgrade. The MSD uses an improved magnetic trigger design and in my opinion is a better peice. Dist failure on these cars, with their age is prevalent.

pvr007

iTrader: (1)

i have the same problem, but apperently people say that it doesnt matter, i mean if its a daily driver, but if you are looking to perfect the car then go ahead and replace it with a new one

henryd3

iTrader: (128)

Grab the shaft and try to wiggle it from side to side and see if there is any play there. If there is, replace it, If not it could still be usable. See how it runs with new cap and rotor. Any loose stuff or broken off pieces in there?

Copperhead

If the pickup coil cover is loose, can it be removed to inspect the guts and then put on tight? Can't be good to leave it rattling around under there. Should I clean this thing with contact cleaner, or silicone spray, or just leave it dry?

I'll inspect it a little closer this weekend. Where to get the correct Delco distributor??

ASE doc

Many auto parts dealers sell AC Delco through their aftermarket network. Do an internet search. I dont remember how the cover is held in place but think it was just stuck on with adhesive. Ive found several that were loose. It doesn't seem to affect performance. Contact cleaner should be fine.

RBob

iTrader: (1)

The cover is held on by a snap ring type of thing. Hard to explain, it is one of those inside serrated washers that is pushed down over the mount, then locks into a groove. They are usually destroyed when removed.

When purchasing a new pickup coil there should be a new retaining washer in the box.

It is normal for the cover to rotate some. As it isn't keyed in place or anything. Just can't turn it past the reluctor poles, which is what stops it from rotating.

It is normal for them to get all rusty inside. This is from the ozone that is generated by the spark jumping from the rotor to the cap.

What I typically do is: pull the distributor out and disassemble it. Check the shaft side play, if OK continue. Check the star wheel, make sure that it is still firmly attached to the shaft. Also check the magnets, they should be in decent condition. If they have pieces missing or are all swollen and cracked then purchase a new shaft assembly.

Then lightly wire brush the star wheel and reluctor and spray them with clear paint.

If the ICM is an OEM GM unit reuse it. Buy a new pickup coil and use it. Clean everything up, use new heat sink paste and reassemble.

Couple of tips: if you shim the shaft to reduce end play, no tighter then .014", the housing expands more then the shaft when it heats up.

To get the shaft out using a gum cutting carb cleaner works great. Spray it into the bottom of the distributor to cut the varnish off the shaft. May need to keep working the shaft up/down & turning while adding more carb cleaner.

When putting the gear back on the shaft, the dimple gets aligned with the slot at the top of the shaft (rotor key). And the gear end of the gear goes on first. The round end of the gear is at the bottom of the distributor.

RBob.

ASE doc

Thanks RBob!

Apeiron

Shimming is a great idea, too