cap and rotor

bassdog · September 6, 2002

Hey guys

While trying to get my engine pulled, we looked at the cap and rotor (needed to get it out of the way for a tranny bolt) and it was pretty worn and a ton of deposits on the cap.

I just bought these new from GM last Nov., so they are only 10 months old!!! What is the usual life cycle of these? I would not think that these would wear down so quick, they look as if they've been on the truck since 94! What problem am I having and will the new motor cure this problem?

Could it be that my timing chain being so worn....

MarkD · September 6, 2002

From what I have seen, there are two main reasons for wear in a rotor button and dist. cap.

1.) Manufacturing variances resulting in either too large or too small of a gap between the head of the rotor button and dist. cap contact or a loose fitting rotor button. There really is no easy way to check this.

2.) High current transfer in the dist. itself. High output coils, bad plug wire(s), bad plug wire contacts are usually the main causes of this.

The deposits can be either rust or burnt ozone. Do you wash your engine? Do you live in an area that has large temperature swings? Do you live in an area with a lot of rain/standing water/high humidity? These things can cause rust on a rotor button.

I can't think of how the motor would cause these problems other than 1.)loose tolerances in your dist. drive gear/dist. housing 2.)blown radiator hose/heater hose.

bassdog · September 6, 2002

The wires, cap, rotor and plugs were all replaced last Nov. When I picked up the engine, the parts guy asked if I wanted tune-up parts and I said no due to the fact these were all only 10 months old. No performance parts of any kind, so that isn't it. I did have one burnt wire, but it has not been burnt long, maybe a month or so. Plugs weren't that great when I checked them, RapidFires...and I regapped them to .40 from .45 at that time...seemed to run better.

I live in New England, so temp. extremes are possible here , but we are in a drought, not much rain to speak of.

Radiator and heater hoses are fine...original, but fine