HT leads and all that

[Justin S]

Just put some new Ford HT leads on my S3 and the distributor cap had a metal surround on the old one which was tatty bent up.I put the new cap on minus this and wondered afterwards,do I need this on for some reason? All I can think is it is some kind of splash guard,unless you all tell me otherwise?
Also,on the cap,I have some in-line resistors?for each lead.Are these needed? I know that my Westfield used to somehow upset the reception to a neighbours TV when I started it up.Is that the only thing it will stop,can I take them out also?

[Mark Adams]

The tin surround is there for suppression, and you could dump it. In my experience it doesn't make much difference.

You can dump the suppressors also if the leads are resistive (at least 5,000 Ohms). I think the plugs are usually resistor types as well, so the poor old thing is stuffed full of resistors. You can always put them back if you get interference problems, although I suspect you will find no effect whatsoever on performance.

Note that some resistance in the plug leads etc., is a good thing. Too little or too much means that the spark becomes self-extinguishing.