Hi Steph
The difference in the plugs is the temperature range, I think the N12Y is a
hotter plug than the N9Y, the R stands for Resister (they have one built in
for radio suppression) and the C stands for copper (they have a copper
core). To determine which is the hotter plug look down the hole at the
business end, the plug with the deeper hole will be the hotter plug as the
depth governs the length of the heat path, the longer it is the further the
heat must travel to be dissipated to the head through the plug body.
I hope this makes sense for you.
Graham.
2500PI MKII
Sprinted Dolomite
2000 MKI
Toledo
1300 Front Wheel Drive
http://members.tripod.co.uk/TriumphIW/index.html
> Just one question. I went to my autopart store and when I asked for the
> spark plugs, the reference number out of their books was Champion RN12YC.
> He said that it replaces the N9Y. I couldn't find the N9Y but saw RN9YC.
> Yet, their book said RN12YC.
>
> The other number on the box said 404CC (RN12YC) and 440CC (RN9YC) i think.
>
> Any thought on that?
|