Light Aircraft Association

Any recommendations for spark plugs for a Rollason Ardem 1834 engine?
The Rollason engine data sheet says Lodge HN or Champion LT which are old designations. The current alternatives appear to be Champion L82C or Bosch W7AC. However the Beetle suppliers all say the original manufacture plugs were Bosch W8AC. I suspect that there is only a little heat difference but I am looking for a more certain opinion.
Also should the plugs be the version with an installed resistor, WR8AC rather than W8AC. The ignition system is the Leburg type.

Ta

Jim

Hi Jim

First of all, a plug with resistance built in will not be a problem with a Leburg system however, if it were running on a mag I would personally steer clear of plugs with built in resistance. The mags have to overcome the resistance and as a consequence will suffer in the long term.

On my Luton Minor and VP1 both utilising Lucas SR4 mags, I made sure the ignition system was screened throughout and leads, plugs and plug caps were all without inbuilt resistance and the screening (well earthed) ensured the RF pulses didn't interfere with radio reception/transmission.

As for a suitable plug, the Bosch WR8AC or AP should be fine.

Many thanks Roger,
I've gone for a set of Bosch WR8AC which happened to be under offer at Europarts for 90p (!) each. These are for my Ardem engine in the Nipper. Last year I gave my SR4 'Peacock' set to a school in Newquay who are refurbishing a FRED. In exchange they have cut the second plug hole in the cylinder heads of the engine that will go in my Taylor Mono. They were set up to do this work as part of their STEM studies. This second set is for 10mm plugs, do you have any recommendation for this size?

Thanks

Jim
02559

I really couldn't comment on 10mm dia plugs as never having used them in a VW conversion however, a quick comparison with the Bosch WR8AC came up with the UR6AC as a likely candidate. The heat range of this plug should be OK for the purpose.

I've been looking for the UR6AC but stuggling to find a supplier. Any suggestions?
Thanks
Paul.