the "Hot" in reference to the plugs refers to the temperature of the
ceramic around the center electrode. The lower compression engines tend
to soot up this area more and the higher temperature helps burn it off.
You want colder plugs for the high compression engines to prevent
pre-ignition off the hot ceramic...
"in the old days" we used to start/warm up the Spitfire race engines
with hotter plugs, then change over to the colder plugs for the race...
Clark
------------------------------------------------------------------------
--
Visit me at: http://members.aol.com/cwnicholls
>----------
>From: Ken Streeter[SMTP:streeter@sanders.com]
>Sent: Thursday, August 07, 1997 3:46 PM
>To: Michael Cline
>Cc: triumphs@autox.team.net
>Subject: Re: Spark plugs
>
>Michael Cline wrote:
>
>> I am confused! I have a 1971 TR-6, what spark plugs should I use?
>> I see in my Bently manual on page 32 it states "N-12Y (N-9Y on
>> 1973-1976 cars)", is this correct? Other catalogs contradict this,
>> such as TRF....N-12Y "hotter plug may be better for later cars
>> with emission controls") What should I use in my '71 and why?
>
>There is much mis-printed information on this in the manuals,
>particularly with contradictions, etc.
>
>I use Champion RN-9YC in my 70 TR6, and Champion RN-12YC in
>my 1974 TR6. The RN12YC is a hotter plug. From what I have
>been able to find in various literature, this is the factory-
>suggested configuration:
>
> Champion N9Y -- 1969-1972
> N12Y -- 1973-1976
>
>Feel free to substitute your favorite brand of plug (NGK,
>Splitfire, whatever).
>
>I don't honestly know why the lower compression engines want
>the hotter plug. Maybe somebody else out there that knows
>can explain...
>
>--ken
>'70 & '74 TR6 Daily Drivers
>
>--
>Kenneth B. Streeter | EMAIL: streeter@sanders.com
>Sanders, PTP2-A001 |
>PO Box 868 | Voice: (603) 885-9604
>Nashua, NH 03061 | Fax: (603) 885-0631
>
|