The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: ShaunMac on 08.10. 2013 14:12

Title: Plug caps
Post by: ShaunMac on 08.10. 2013 14:12

Hi all,

Just been making some new ht leads up and realised my spark plug end caps are 10 ohm resistance.
Will this be an issue?
Should I get non-resistance ones?

Thanks,
Shaun

Title: Re: Plug caps
Post by: bsa-bill on 08.10. 2013 14:34

Yes, it's the advice always given

Title: Re: Plug caps
Post by: beezermacc on 10.10. 2013 09:37

Actually, 10 ohms is next to nothing and should not affect running at all. Plug caps known as 'suppressor caps' often have upwards of 10,000 ohms resistance; these are the ones to avoid. Your plug caps are probably designed to be zero resistance, 'straight through' types, and there may be some reason to do with their construction, maybe the materials used, why they have a little bit of resistance. As plug caps are only a couple of quid I'd probably get some new ones anyway.

Title: Re: Plug caps
Post by: Triton Thrasher on 10.10. 2013 18:15

He probably meant 10 kOhm.

Title: Re: Plug caps
Post by: ShaunMac on 12.10. 2013 15:59

Thanks guys. Sorry, yes, did mean 10k ohms.

Title: Re: Plug caps
Post by: terryk on 15.10. 2013 13:33

Dont use them with magnetos

Title: Re: Plug caps
Post by: a10 gf on 15.10. 2013 14:14

Use the 'straight trough' rubber caps, they fall apart\disintegrate after some time (my experience) but have no RF filter\restrictions and does not weaken the magneto spark. Cheap to buy and keep some spares. Example (http://www.ebay.co.uk/itm/BSA-CLASSICS-BLACK-RUBBER-SPARK-PLUG-CAPS-/390676795204).