Lucas Dizzy Caps

[type26owner]

My parts guy pointed out a potential problem if you're using carbon conductor wires in the older dizzy caps which have a conducting screw which pierces the wires to establish electrical contact. This is great for copper standed plug wires. It's a potential problem with the carbon conductor type wire though. There is not enough surface area contact between the sharp end of the screw and the carbon conductor in the wire. The workaround is to add a 3/32" x 1/2" long thin brass strip which you slide in between the carbon center core and the insulating sleeve. Leave it stick out and wrap it around the insulator so you can clock the wire end into the cap's hole orienting the shim is on the screw side. The screw is then pierced through brass shim apparently greatly reducing the resistance of the electrical connection. Don't know if this really helps but it certainly sounded plausible. Oh, the better parts stores sell the brass inserts also I'm told but he was out of them.

[mikefromengland]

no need.i use carbon conductor wires with no probs.push in the wire then before you put in the screw use a bradall to pearce the wire then put the screw in.the screw holds in the wire as well.mine work perfect like this.

[type26owner]

Hi Mike,
Being a Yank I have no idea what a 'Bradall' looks like. Could you post a link to a picture? Thanks!

[tdafforn]

Bradawl - thin spikey screw driver shaped device used in woodwork to open up a pilot hole for small wood screws.
Or more formally from a dictionary "an awl for making small holes for brads or small screws"
Cheers
tim

[type26owner]

Mike,
The problem is not the ability of the contact screw to pierce the plug wire. It does that quite well. The problem is the electrical connection is one with very high resistance. The carbon is an electrical conductor but not as good as a metal. The electrical contact area must be increased to compensate for this effect.

I've never experienced this problem because the aluminum lugs in the cap would burn up before a wire connection would open up causing a misfire. A set of plug wires are so cheap I never try to reuse them.

BTW, the Beck-Arnley and Standard and the KIM brands dizzy caps are all aluminum. Suspect the brass ones are coming from NAPA.