Oxidising distributor point

[85_Calais]

One of the points on my distributor cap is oxidising with a similar residue that appears on car batteries. Can anyone tell me what causes this and whether it is likely to have any impact on the quality of the spark?

[ari666]

only one of the points?

all of them will do it eventually. it is oxidisation from the electrical current passing from the rotor button to the cap. will it have impact on your spark? absoluteley.

if its only one point i would be looking at the condition of your spark plug and lead on that point.

[85_Calais]

As always thanks for the advice!

Yeah it's only happening on one point...strange. Looks like I'll be buying a new distributor cap this weekend, as I think this may be the cause of it sporadically backfiring on LPG. The spark plugs and leads were only changed recently but will check them too.

[ari666]

hmmm, TBH i have never really seen only one point do it. i cant really think of a good reason why it would be either, sorry. but i will bet 100 bucks itll be the cause of your backfiring.

[Darren_L]

if your cap is worn out, it is more likely to occur as the spark is jumping a larger gap.
buy a new cap and keep an eye on it. All caps will eventually get the build up, but over time

[vkberlina]

do rotor button and cap at the same time, also for a bit of trouble shooting mark that point on the cap and the lead and switch the lead with another the same length and see if the oxidisation changes position, this will show if its a faulty lead. You could also change the spark plug to a different position and see if it affects it also. My money would be on rotor and cap though.

cheers
Scott