How to use HT lead acorns and brass discs?

[jansens]

I am a bit ashamed I need to ask this but how exactly do you use the acorns and the little brass disc with the hole and slit in it when attaching leads to the distributor?

Obviously the central core goes through the hole in the disc but then what? Are you meant to fold the core back and somehow catch it with the slit? Or is the slit just there to provide a step to catch the wire as you tighten the acorn down, a bit like a split lock washer?

Whatever way it goes there doesn't seem to be any cable strain relief at all. It's all just held by that central conductor.

Simon

[john williams]

Simon, simply spread the exposed copper strands out like a "star burst", they are  then gripped by the brass washer when the acorn is tightened. John

[jansens]

Hi John, that makes sense for normal wires. I failed to mention though I am using the non copper wires sorry. These are the Accuspark carbon core leads. The central core is a strong coil of sorts, but a single strand if that makes sense. It could be unravelled but not spread out like a normal multi-core wire.

The carbon core is very tough. I was surprised actually. I actually cut off the modern booted plug ends and put on my own crimped ring connectors then some black heat-shrink over them. I was able to double the core and do a very solid crimp using the proper tool on the plug end. I use thumbscrews to hold them on.

I suspect just poking the solid core through the hole and folding it over will be enough to make a decent connection. I just wondered how other people did it.

Simon

[bob46320]

I used to cut off a bit of a paperclip, bend one end into a circle (size of your washer) and the other end, bend perpendicular to the circle and push it into the carbon conductor. It only needs to be long enough to grip into the carbon core. Crude, but effective.

[Peter Johnson]

The accuspark carbon leads with my electronic distributor came with some gold plated bent paper clip type things that push up the end of the lead. From memory, they were flat sheet folded into a U shape and cut with a pointy end and barbed edges.

Peter

[JonE]

just watch that your brass inserts are all the same depth in the accuspark distributor cap, as of course you need the pressure provided by the acorn to create the contact. This should be obvious by the lead getting tight but I missed the problem first time round just because I wasn't expecting it.

[jansens]

I worked it out in the end. The Accuspark stuff really needs better documentation. I needed to change the plug lead ends to right angle ones and it was then I realised the kit came with the little brass spikes and that on their website they show those being used: https://www.youtube.com/watch?v=7QuGG7wIGj0

That's for the conventional ends. I used the same idea for the Acorn ends. Bob46320 and Peter mention the answer. I just made my own spikes from solid copper wire and pushed them down the centre and then folded them over. That did the trick. Bending the copper into a circle is probably even better.



I still don't like the lack of strain relief on the wires but I guess that was normal back then.

I got it all working and bench tested it and have sparks so that's all good now.



Russell might recognise the battery! 

Oh, another bad thing about the Accuspark was the oiler tube. It was aluminium on mine and meant to thread into the body (on a 6mm thread) but the thread on the tube on mine was stripped. I made a new one from some brass tube soldered to a 6mm brass screw drilled down the centre.

Tomorrow I might see if the engine actually fires. One other thing with electronic ignition is it's tricky to set the static timing. With points you can see where they open. With this I guess I need to just guess? And err on the more retarded side?

Simon

[Ruairidh Dunford]

You can either use a volt meter on the lead to detect when it fires or simply set the rotor arm pointing to the very corner of the baseplate - that always works for me.

[jansens]

I actually just removed No. 1 lead and hooked it to another loose plug sitting on a head stud then I was able to rotate it and see where it sparked. I am in about the right place I think. I could see the voltage on the meter too. An analogue meter would be much better than my digital here.

[mk1-mark]

It is also possible to attach the little brass discs with small brass screws, these give a more positive connection than the paper clip thingies. Funnily enough, I was doing exactly this at the weekend.