Spark Plug Type
#1
Spark Plug Type
Looking for spark plugs for my X300. Handbook calls for Champion RC9YCC which I can't find but can find RC9YC at a very good price. Can anyone tell me the difference between the two. In other words what does the extra C stand for.
I would be interested in any other recommendations that you have had good luck with.
Thanks.
EZDriver
I would be interested in any other recommendations that you have had good luck with.
Thanks.
EZDriver
#2
The C indicate a copper core to the electrode, so its not essential. Don't be tempted to use the equivalent NGK plug to a Champion RC9YCC. Generally I think NGK make excellent plugs, but for some reason they don't seem to work well in the AJ16 engine. For the same reason I can't recommend other plugs that weren't the one originally specified. You could also choose to use a harder/colder plug such as a Champion RC8YCC. I actually use RC6YCC plugs in my uprated AJ16 SC engine without experiencing plug foluing problems, but then I never drive my car round town or start it below about 5degC.
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EZDriver (07-13-2012)
#5
Thanks guys. It seems that the car is pretty tolerant on plug ranges. I have had the car for eight years. About six months after I got it I decided to change plugs even though it was running great. I looked in the book and it said RCY9CC. But when I pulled the old ones out they were RCY12CC plugs. I had forgotten that until I realized I had kept the old plugs since they were in such great shape. Since they were in good shape when I took them out I decided to buy the same plug except without the final C as it was not available. What is in the car right now are Champion RYC12C plugs. I'm tempted to disregard the book and replace with the same plug. The plugs in there now have about 50K miles on them.
Any comments??
EZDriver
Any comments??
EZDriver
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EZDriver (07-15-2012)
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#8
I don't know. I've always used the EBC8143's in my car and never had a problem.
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EZDriver (07-15-2012)
#9
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Doug, I was trying to find that referenced bulletin. I found one that stated that the proper plug was the EBC 8143 (RC9YCC) for naturally aspirated but the supercharged engines kept the old AJ6 EBC 11480/1 plugs. Is that what you are referring to? All other research shows the 8143's for all AJ16 applications. I also remember hearing about the 12 cyl cars getting hotter plugs but cannot find that one.
I don't know. I've always used the EBC8143's in my car and never had a problem.
I don't know. I've always used the EBC8143's in my car and never had a problem.
I think that's it.
Here's what I have......which I believe is a *supplement* to an earlier bulletin (which I don't have)
05.1-07
Date
2-95
Amended 12/98
Model 1995-97 MY
Sedan (4.0l) Range
VIN 720001-812255
Spark plugs-AJ16 Engine-
Change in specificcation
ISSUE:
The spark plug specification is updated on all AJ16 (4.0L) Sedan Range vehicles to include supercharged engines.
Hotter spark plugs (part number EBC 8143) were installed on supercharged engines in production from 1997 MY.
ACTION:
Use the following spark plugs as service replacements in all AJ16 engines:
ENGINE PART NUMBER PLUG GAP TORQUE
AJ16 (4.0l) EBC 8143 0.9 mm (.035 in) 22-28 Nm (17-20 lb ft)
Cheers
DD
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EZDriver (07-15-2012)
#11
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Here's this as well. It's the earlier bulletin
http://www.jagrepair.com/images/TSB/...6%20Engine.pdf
Cheers
DD
http://www.jagrepair.com/images/TSB/...6%20Engine.pdf
Cheers
DD
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EZDriver (07-15-2012)
#12
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I'm confusing myself, I think. Not sure.
My notes show that the EBC 8143 = RC12YCC
Since the bulletin calls for *hotter* spark plugs, and in Champion-speak, higher number = hotter plug, it would make sense that the "8143" would be a #12 Champion, not the #9 Champion.
Hmmmm.
I have nothing to do right now, and a full pot of coffee. I'll do some more checking
Cheers
DD
My notes show that the EBC 8143 = RC12YCC
Since the bulletin calls for *hotter* spark plugs, and in Champion-speak, higher number = hotter plug, it would make sense that the "8143" would be a #12 Champion, not the #9 Champion.
Hmmmm.
I have nothing to do right now, and a full pot of coffee. I'll do some more checking
Cheers
DD
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EZDriver (07-15-2012)
#13
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Here's another bulletin. if you scroll down it says that EBC 8143 = RC12YCC
http://www.jagrepair.com/images/TSB/...rivability.pdf
Cheers
DD
http://www.jagrepair.com/images/TSB/...rivability.pdf
Cheers
DD
#14
Thanks guys. You have all been a big help. One other thing I remember just a short time after buying the car which would be about seven years ago, I met with a good Jag tech in Dallas. I asked him how often I should change spark plugs. He said every 15,000 miles which I thought was way too often. I now think the reason for that was because of the use of RC9YC plugs which was what he was used to. The ones I removed shortly after that were RC12YCC pluge and they were in great shape which was why I replaced them with the same minus the last C.
What I will do is evaluate the condition of the plugs that are in there now and make the decision then as to which plug, 9 or 12, to go with. I won't be doing this right away but will post the results as soon as I can.
Thanks again.
What I will do is evaluate the condition of the plugs that are in there now and make the decision then as to which plug, 9 or 12, to go with. I won't be doing this right away but will post the results as soon as I can.
Thanks again.
#15
Here's another bulletin. if you scroll down it says that EBC 8143 = RC12YCC
http://www.jagrepair.com/images/TSB/...rivability.pdf
Cheers
DD
http://www.jagrepair.com/images/TSB/...rivability.pdf
Cheers
DD
Man, I missed that one. I always thought the 8143s were 9s.
#16
Interesting stuff and useful opinions. I don't really have a question, but just thinking out loud here. I've been keen to change the standard Champions on my NA 3.2 Sport, hearing so often that NGK's are superior to Champions, and that iridium's or platinum's will enhance performance in terms of starting, acceleration and fuel economy (although I haven't experienced problems with any of these things while running on the Champions) so now I'm in real doubt, especially about iridiums and platinums, I wonder if these hot plugs will end up causing engine damage. They are hugely expensive and now I suspect they may be waste of money.
I've ordered one of Andy Stodart's modified Crank Sensor Brackets which I hope will deliver the performance & economy improvements I'm looking for, so maybe I'll just get new RC12YC plugs to complement that in view of Doug's and XJRengineer's comments on the plugs.
Cheers,
Tony.
I've ordered one of Andy Stodart's modified Crank Sensor Brackets which I hope will deliver the performance & economy improvements I'm looking for, so maybe I'll just get new RC12YC plugs to complement that in view of Doug's and XJRengineer's comments on the plugs.
Cheers,
Tony.
#17
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FWIW the only reason I went to the NGK Iridiums is that, according to a person whose opinion I value, they're supposed to be easier on the notoriously troublesome X300 coils.
Maybe so, but I started having coil problems at about 100k miles....just like everyone else :-)
I agree....save your money!
Cheers
DD
Maybe so, but I started having coil problems at about 100k miles....just like everyone else :-)
I agree....save your money!
Cheers
DD
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jagent (07-26-2012)
#18
Looking for spark plugs for my X300. Handbook calls for Champion RC9YCC which I can't find but can find RC9YC at a very good price. Can anyone tell me the difference between the two. In other words what does the extra C stand for.
I would be interested in any other recommendations that you have had good luck with.
Thanks.
EZDriver
I would be interested in any other recommendations that you have had good luck with.
Thanks.
EZDriver
last year i replaced the stock ngk's on my 1995 x300 with some other premium sp
had all sort of missing when the engine got hot
went back to ngk and the problem disappeared
i measured how far the electrode stuck out from the base of the thread
and i found that the ngk was about 1/16' shorter
#19
#20
ngk's
in my great wisdom i replaced ngk with some other super prmium platinum or iridium plugs ( forget the brand though) and for a slong as the engine was not hot , it would run ok , when it got hot ( i live in Florida) it started stumbling and missing badly
Last edited by aldol; 01-17-2013 at 07:52 AM.
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RJ237 (12-20-2012)