Hi Dennis, Very interesting to read about another option for switching our 4's to EI ! I think that your method of determining the firing point would also work for other brands of units to set the initial point for static timing which would be very useful. Am I right in thinking that the 15 degree A...

Gui - that's exactly what I've done. It's possible to remove the cap without disturbing the front pipe and I've just used typing correction fluid to make white base marks on both the crank bolt and the casing and then ink-marked radial lines for TDC and fully advanced using the standard rod-in-plug'...

Thanks both - Powerspark sounds good. I like that plastic film - clever stuff, will likely order some - £2.45 for a small piece seems good. I'm going to take some pics of my timing marks and post to see if others think this is a decent way of strobe timing. Seemed a simple solution to me although pe...

It was possible to do this by comparing it with the unit on my other square four Touch of class there Paul ;) My distributor is complete and original but there is wear. When I got the bike is was a complete wreck and I was relieved that things like the distributor, generator and drive mechanisms we...

So, I now know that both use mechanical advance retard, Thorspark the original and Powerspark a replacement system. I'm surprised that Powerspark don't go the electronic route as I would have thought that cheaper and easier than building a new mechanical system into a modern replacement distributor ...

I hadn't realised that the Powerspark system used a mechanical advance/retard, I was hoping to go solid state but not sure that's an option unless I make other changes to the electrical system. I've now emailed Thorspark for some more details. Their web site is a bit odd - it suggests that they only...

I contacted Powerspark and here's their reply: Hi Bernie - the DK4A distributor we supply (our part number D31PP for the positive earth version) is intended for the Austin 7. It rotates clockwise and will work with 6v or 12v, but the drive gear will be different to your Ariel. It's possible that you...

Thanks again all for the tips and your ideas - just thinking my earlier idea through overnight I realise that if I did try it I would need to use two control units rather then trying to trigger one from four coils connected together - otherwise the advance would be wrong. If I've thought it through ...

I'm now wondering about modifying a system designed for twins. By either using four trigger coils on one rotor plate - a mod to the circuitry - or two boards mounted back-to-back and rotationally offset by 90 degrees I could then machine a standard rotor to fit on the distributor shaft and enclose t...

Many thanks again for your thoughts and replies. I'll check the dashpot again although I have spent some time checking that it moves freely during the rebuild so probably not that. There is quite a lot of rotary slack in the rotor arm. Some of this might be worn springs - I'm ordering a new set shor...