melting point

[Alastair]

I'm probably being really stupid here, but why did the plastic insert on my points (1300 Ital engine) keep melting. It stopped after the last strip down but I'm intrigued.

[Scott]

Which plastic insert?
If you mean the one the distributor cam operates, then this is probably due to lack of lubrication. A small amount of grease should be smeared on the cam to lubricate this plastic piece.
If you mean the insulating collar for the points spring, then the only reason I can think of why this is melting is due to a short in the points pivot point where this collar sits. Current must be flowing at times across this short to generate heat in order to melt the plastic piece. This seems unlikely as the short would also affect the engine operation, ie: misfiring, not starting.
Hope this is of some help.
Regards, Scott.

[Alastair]

Sorry - I should have been more specific. It is the plastic insert which includes the heel which bears against the cam which was melting - two new sets of points in succession. I had installed and lubricated the felt which bears against the cam and it did not appear to be the heel wearing. What seemed to be happening was that the pressure of the spring was compressing the melted plastic enabling the points to close up. I'm actually wondering if the points themselves were defective - the ones fitted now are of a different make..... Thanks for the reply, by the way!
Alastair

[Kevin]

What seemed to be happening was that the pressure of the spring was compressing the melted plastic enabling the points to close up.

I think you must be right about the points being deffective somehow as I have not come across the plastic melting before so something must have been shorting, but I have seen severe wear on the heel which is because the outer surface of the cam has not been lubricated as scott said, this is as well as the felt inside.