Distributor squeak, semi-new cap

About 5 months ago I installed a new cap wires and plugs, also a small white ceramic inset that spins inside the cap. I started my car yesterday and there was a low pitched squeak coming from the cap (If you push on the cap it stops but once you let go it continues.) Its the same sound as bad breaks, a on-off-on-off squeak but not as high pitched. I removed the cap and there is a little carbon and no real signs of rubbing under the cap, any suggestions?

Thanks for any help and ideas,
MP

Need more info. What year, which engine, how many miles, etc.

Ah, right, my mistake.
90 Caprice classic 4dr sedan, 305 5L Fuel injected. About 118,200 miles, maybe 6 months and 3-4000 miles on the new distributor cap, wires, rotor and plugs.

did you get the rotor pressed on the distributor all the way? I had that kind of noise on my 88 c1500 and I hadn't pushed the rotor on enough.

I would definitely say the noise is the rotor not pushed down far enough onto the shaft. I've had the same thing happen with mine.

I'm fairly sure I had, I'll take the cap off tomorrow and check, I made a quick run up the road, the sqeaking stopped after I drove 1/4th a mile after a 1 and 1/2 minute warmup. It was about 60F outside. Would tapping the rotor down with a rubber mallet ensure its all the way down or would that be detramental? Thanks again for the help.

I'm fairly sure I had, I'll take the cap off tomorrow and check, I made a quick run up the road, the sqeaking stopped after I drove 1/4th a mile after a 1 and 1/2 minute warmup. It was about 60F outside. Would tapping the rotor down with a rubber mallet ensure its all the way down or would that be detramental? Thanks again for the help.

You should never "assist" a rotor install with anything other than your hands - it can easily be broken. The "key" in the shaft portion of the rotor can break off and cause ignition timing maladies.

It was so much simpler with the screw-on rotors!

Makes sence, seeing as its all ceramic and plastic. I figured I'd ask about the "If it don't work, hit it with a hammer" approch. Thanks again.