The higher the number, the hotter the plug, at least for Champion. So the N9
is cooler than the N12. You mentioned that the new set, unlike the older,
has extended tip, but the 'Y' designation on any Champion plug indicates an
extended tip, so both should have extended tips. If memory serves me
correct, on Champions the N is the series indicating the reach of the
threads, the numeral is the heat range, R is a resistor plug for radio
reception, Y is extended tip, and I'm quite sure, but I believe that the C
indicates wider pre-set gap for newer electronic ignitions.
Also, if I recall, the original Champions for the U20 were N5, or N3 if you
wanted it a bit cooler. The extended tip equivalents were N9Y and N6Y.
Jerry Krakauer
----- Original Message -----
From: "James Cawrse" <nqrithfordatsun@msn.com>
To: <datsun-roadsters@autox.team.net>
Sent: Wednesday, July 21, 2004 9:46 AM
Subject: Spark Plug Evaluation and Question
> Dear List:
> This goes hand in hand with my previous post about plug wires. Of course,
> since I broke a
> spark plug, I needed a new set. Bucking the trend for NGK plugs, my car
has
> been
> running well for some time with a set of Champion RN9YC plugs, dont
remember
> how
> I arrived at this set being good for a roadster, but it ran great with
them
> for some time.
> They are very dark gray, almost black, so the heat range is OK, maybe even
> one step too
> cold.
>
> My local auto parts store had a listing for a 67 Nissan 1600! So, the
> Champions he came back
> with were not the same though??!! They are RN12YC. These plugs have an
> extended tip, compared to the previous set.
> Well anyway, I put them in. The car seems to run fine, in fact it seems
to
> start much quicker, with no choke when cold.
> Apparantly the pistons dont hit the extended tip either, because the car
is
> running fine......
>
> My question to the list is: Can someone out there tell me how these are
> different than the
> old RN9YC set? If the heat range is significantly hotter, I could be in
> trouble with
> pre-ignition once I start driving the car fast again.
>
> Thanks for any advice!
> Jim
> Chesapeake, Virginia
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