N-9YC is the recommended and middle of the road plug. A colder plug is
the N-7YC and colder again is N-6YC. The coldest plug available for the
MGB was the N-60 but I don't believe it exist anymore. and a hotter plug
is the N-11YC and N-12YC. On a hotter than standard engine, i.e. hotter
cam, port and polished ect. you should run a colder plug in the #2 and #3
since these run hotter. A hopped up street engine could use N-9 in #1,#4
and a N-7 in #2, #3. Full race would use N-7 in #1, #4 and N-6 in #2,
#3.
For further clarification the Y in the model number denotes that the
electrode extendeds beyond the end of the core well. So a N-9C the
electrode is flush with the bottom of the plug.
----------
From: mgs-owner[SMTP:mgs-owner@autox.team.net]
Sent: Tuesday, August 20, 1996 5:56 PM
To: mgs
Subject: spark plugs and carbon
Greetings all!
Got the MGB out of mothballs and on the road for the first time since
1990. Been driving it for 3 weeks and am still getting the small bugs
out. I have a few simple question I thought someone might know
something about:
1. What is a "cold" spark plug that can be used in the MGB? Also, what
is a "hot" plug (don't say it's just the opposite please ;)) and where
does the Champion N-9Y fall in this temperature range?
2. Is there an easy way of decarbonizing the combustion chambers
without taking off the head? I'm experiencing nasty dieseling and it's
not related to timing. Had a carb mixture problem that I've recently
fixed.
Hope this stuff hasn't just been covered since I've been off the list
for the last 2 weeks and not even realized it (been kinda busy catching
up with an old friend). Thanks always.
Dave Hay
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