correct spark resistance

[Deleted member 12676]

If you use a spark plug with resistance (such as Iridium plugs) then you need to use a non-resistor spark plug cap. Otherwise the spark current will be reduced for a weak spark. And if you have a non-resistor spark plug and a non-resistor spark plug cap then the excess spark current may burn out your high voltage coil. With small engines every little nit-picking thing is important.

 

[FurryOnTheInside]

Thanks. Noted.

 

[Frankenstein]

If you use a spark plug with resistance (such as Iridium plugs) then you need to use a non-resistor spark plug cap. Otherwise the spark current will be reduced for a weak spark. And if you have a non-resistor spark plug and a non-resistor spark plug cap then the excess spark current may burn out your high voltage coil. With small engines every little nit-picking thing is important.

Interesting, I think I asked before but forgotten, how do you check the cap for being resistive or not? Maybe in your website probably?

 

[crassius]

zero resistance in plug, wire, and cap works best - caps have resistance coded in the part number

 

[FurryOnTheInside]

Doesn't it scramble nearby electronic devices if there's no resistor plug or wire/cap? Or am I remembering that wrong..

 

[crassius]

nearby is relative, it won't hurt your neighbor's wifi (pretty much the same as any points&distributor car) - it will hurt your spark if you put resistance in

 

[FurryOnTheInside]

nearby is relative, it won't hurt your neighbor's wifi (pretty much the same as any points&distributor car) - it will hurt your spark if you put resistance in

I was thinking more of Frankenstein's question of how to tell if the cap has no resistor... and also a wireless bicycle computer and my Bluetooth speakers connected to my phone.

 

[Frankenstein]

Doesn't it scramble nearby electronic devices if there's no resistor plug or wire/cap? Or am I remembering that wrong..

I was thinking more of Frankenstein's question of how to tell if the cap has no resistor... and also a wireless bicycle computer and my Bluetooth speakers connected to my phone.

Resistors will prevent or at least help with certain electromagnetic interference, or so I've read.

Apparently there's this good read I found when trying to answer this question: http://forums.sohc4.net/index.php?topic=67096.0

There's a piece of text I think is relevant, stating "NOTE: NGK makes caps in 0 ohms, 5000 (5k) ohms, and 10,000 (10k) ohms types. Pick the right one!"

That would lead me to believe that if I were to remove the cap and hook my multimeter up to it I should be getting 0 or very close to 0 ohms, while a resistor type should be around 5k ohms on average.

The resistance goes up as the plug ages (which makes sense because that's what resistors do right up till they die at infinity ohms,) so that means that even our bikes could be victimized by a bad cap..

I'm wondering the ohms on my iridium plug is suddenly, and my wire and cap too...

 

[crassius]

NGK and others have part number charts online that show how to read resistance from part number - also the size & angle etc.

 

[Frankenstein]

NGK and others have part number charts online that show how to read resistance from part number - also the size & angle etc.

I bet, but what does that tell us of the millions of nameless brand caps that come with our kits...