how do you clean ignition points?

bigchillcar · bigchillcar's Garage

hi gang,

curious as to what a mechanic physically does when he cleans points that have closed. my '74 911 stalled after idling erratically and wouldn't restart...at least until my wrench cleaned and re-opened them (they didn't have replacement immediately available). i plan to order a couple pair to have available, but in the meantime, should they close again is there anything i can do on the road to 'get me going again'? thanks.

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Rot 911 · 03-14-2002, 10:29 AM

All they are doing is taking a small file, like a fingernail file or emery cloth and cleaning the burns and pits off the face of the points where they close together.

Early_S_Man · 03-14-2002, 10:40 AM

If your wrench did it right, you don't have to worry about them closing up for another ... say, TWO YEARS! And, the CDI-system doesn't cause much burning at all ... most dirty points just need degreasing and wiping off with a lint-free rag, prior to reinstalling. Scotchbrite is 'strong' enough to clean any 'tarnish' off a tyypical set of points in a CDI-system!

boyo · 03-14-2002, 10:40 AM

You might be surprised - my local AutoZone had points for my '72 in stock and for about $4. Maybe not the best quality, but fine for keeping for emergency needs. Just in case you need a part quick.

-Boyo

Jorgeman · Jorgeman's Garage

Bigchill--the cleaning your wrench did was secondary to the regapping--which is an adjustment you can easily learn to make. An old timer's trick is to use a folded dollar bill to burnish the point after filing but it sounds like your problem was the point gap. Also, make sure there's a little lubricant on the points pad.

Early_S_Man · 03-14-2002, 02:17 PM

The reason I mentioned tarnish rather than burning ... is that the points are only carrying 60-70 mA (0.060-0.070 Amps) as a trigger signal to the CDI-unit, instead of the typical 7-12 Amps of a typical battery-coil ignition system set of points!

And, Jorge is quite right about the 'cleaning' being secondary, and, it was most likely unnecessary!

The points closed up because of either wear (lack of lubrication)on the rubbing block, or loose screws securing the set of points, or a combination of the two!.

Superman · 03-14-2002, 02:17 PM

I have some different ideas I guess. First, filing points is for cheapskates (no bigger cheapskate than me). They should really be replaced, rather than filed. New points have a coating...burned and filed points do not.

Gapping would be secondary to filing, rather than the other way around. File first, which changes the gap, the regap them to the correct dwell angle. Then check the timing. Finally run a CLEAN piece of non-shiny and non-waxy paper between them.