What Champion Plug ru Using in you 340?

[66fs]

Well I looked in my old Motors Manual

N9Y from 1968-1972
N12Y in 1973

I always ran N9Y in the 340's and N10Y in the HP 273's regardless of compression. Always looked good, never a problem.

 

[340inabbody]

Yeah, if you guys notice I didn’t ask what brand you run I asked which particular plug you run in the champion series. I’ve seen so many threads here and other places about one particular plug over another, especially bashing champion. I didn’t want this thread to become that, but I kind of thought it would anyways.

 

[Locomotion]

For instance, a 73 340 calls for a 14 where a 68 340 calls for a 12. I don't think any used a 9.

Motor Manual, Chiltons Manual and my memory reflect my posted #'s.

Who had your numbers?

 

[340inabbody]

While you guys are blabbing, I am wrenching. As usual lol

 

[LO23M8B]

Well they lied to you. They used to sell n12y, n11y, n10y and n9y. Now they don;t sell the inbetween ones. So n11y would be one heat range colder. I've run all of the above in my 340's without issues although in the hotter motors I used n10 or n9. In my Hemi it was n63y's.

 

[Newbomb Turk]

Well my block is a 73 running J heads with TRW 12:1 pistons. Compression is a little high on pump gas as it’s not stock so I want to go with one heat range from stock. Which I believe to be rn9yc or n9y not sure of the difference.

When you go to Champions ******* web site they use different part numbers like 405 for some dam reason.

Then you go to technical help they have no heat range charts or anything but they do show you how to change oil!

Dam retards over there or maybe someone can prove me wrong and show that Im the retard.

Do NOT use a 12 Champion with that compression ratio.

You will kill **** so fast your head will fly off.

You are in race plug territory not street plug ****.

You need to start with a C63CX and keep an eye on it.

Depending on the load the plug will see you may need a C61YC and if you want to use an extended tip then start with the C61YC and tune from there.

Do NOT use a 12 or a 9.

You are in race plug territory.

Pay the money for a race plug and be glad you are doing it.

 

[Newbomb Turk]

Lmao, from my original '69 operators manual

View attachment 1716490531

It ain’t 1969 anymore

 

[Newbomb Turk]

68-72 340 per Champion dealer catalog is N9Y

WRONG.

The OP isn’t running a 10:1 compression ratio.
That is WRONG.

 

[318willrun]

Do NOT use a 12 Champion with that compression ratio.

You will kill **** so fast your head will fly off.

You are in race plug territory not street plug ****.

You need to start with a C63CX and keep an eye on it.

Depending on the load the plug will see you may need a C61YC and if you want to use an extended tip then start with the C61YC and tune from there.

Do NOT use a 12 or a 9.

You are in race plug territory.

Pay the money for a race plug and be glad you are doing it.

 

[Newbomb Turk]

While you guys are blabbing, I am wrenching. As usual lol

View attachment 1716490542

I can’t see what that plug is but if it doesn’t cross to a Champion racing plug heat range don’t use them


No ******* 340 EVER came with 12:1 compression.

So any FSM is 109% irrelevant and 100% wrong.

 

[318willrun]

Do NOT use a 12 Champion with that compression ratio.



You need to start with a C63CX and keep an eye on it.



You are in race plug territory.

Pay the money for a race plug and be glad you are doing it.

It's really not that expensive. Rock Auto has them for 2.43 a plug.
More Information for CHAMPION 298

 

[LO23M8B]

I didn't see it was a 12 to 1 motor. Do as newbomb said on the plugs and don't be cheap on the fuel also. It's gonna cause a lot of damage if you are trying to use pump gas. I've got one car with a 12 to 1 with iron heads 340 and I pay for the 110 race fuel. And you can mix it up some. If you want to run pump gas get a Honda.

 

[A56]

It ain’t 1969 anymore

 

[Bennoel 10]

Well my block is a 73 running J heads with TRW 12:1 pistons. Compression is a little high on pump gas as it’s not stock so I want to go with one heat range from stock. Which I believe to be rn9yc or n9y not sure of the difference.

When you go to Champions ******* web site they use different part numbers like 405 for some dam reason.

Then you go to technical help they have no heat range charts or anything but they do show you how to change oil!

Dam retards over there or maybe someone can prove me wrong and show that Im the retard.

Iirc they started out as N9Y, then superseded to RN9Y, and finally to RN9YC. The R is resistor. Again I believe this was to eliminate the static interference on our 2 watt AM radio. Yeehhaaaa!!
Finally the C is just copper core. This is all from my limited memory.

 

[str12-340]

and there are superior Champion plugs as compared to the "C" copper electrode (eg: platinum). Copper was a step up 20 years ago, but not top of the line now.

 

[Bennoel 10]

Well back in 71 that epa mandate changed compression across the board. My 71 454 dropped to 8:1!

I wonder what the C means on the Champion plugs. Another thread someone like Yellowrose or someone said it was a “better quality “ plug wtf?

I believe the "C" just denotes copper core ?

 

[340inabbody]

I really am more concerned about readability than a name. Champions I understand are easier to read.

 

[340inabbody]

Do NOT use a 12 Champion with that compression ratio.

You will kill **** so fast your head will fly off.

You are in race plug territory not street plug ****.

You need to start with a C63CX and keep an eye on it.

Depending on the load the plug will see you may need a C61YC and if you want to use an extended tip then start with the C61YC and tune from there.

Do NOT use a 12 or a 9.

You are in race plug territory.

Pay the money for a race plug and be glad you are doing it.

Thanks Ill search for the heat range chart for these and install the C63CX after I understand where they sit in the chart.

 

[Newbomb Turk]

It's really not that expensive. Rock Auto has them for 2.43 a plug.
More Information for CHAMPION 298

Yeah, the CX series plugs are more expensive.

And as my junk goes that’s probably what I’ll end up needing.

 

[Newbomb Turk]

and there are superior Champion plugs as compared to the "C" copper electrode (eg: platinum). Copper was a step up 20 years ago, but not top of the line now.

Not for these engines.

They don’t need rare earth metal plugs. Waste of money.

 

[340inabbody]

Do NOT use a 12 Champion with that compression ratio.

You will kill **** so fast your head will fly off.

You are in race plug territory not street plug ****.

You need to start with a C63CX and keep an eye on it.

Depending on the load the plug will see you may need a C61YC and if you want to use an extended tip then start with the C61YC and tune from there.

Do NOT use a 12 or a 9.

You are in race plug territory.

Pay the money for a race plug and be glad you are doing it.

What does a race plug do differently than the standard plug? Reach? What does that do/for to the combustion?

 

[Newbomb Turk]

I really am more concerned about readability than a name. Champions I understand are easier to read.

For me they are. My dad was teaching me to read plugs since 1974.

All we ever used were Champions. I’ve never had a bad plug.

In fact, when I started going riding by myself when I could drive I would call everyone going with us, find out what bike they were riding and got a Champion plug for their bike so when their **** fouled I could swap in a plug and get them back.

And I always took my plug back.

I made pretty good money as a 14 year old kid tuning up 40-50 year old men’s bikes.

In fact I was taking plugs for other guys before I started driving.

If I’m getting paid to tune something the first thing I do is pick a Champion plug I think it needs and replace whatever they have.

 

[str12-340]

Not for these engines.

They don’t need rare earth metal plugs. Waste of money.

The question is how long the electrode functions before before it loses efficiency. There's a reason that new vehicles go 100,000 miles between plug changes, but I guess if you don't drive your car much (if at all) it doesn't make a difference..

 

[Newbomb Turk]

What does a race plug do differently than the standard plug? Reach? What does that do/for to the combustion?

If it’s a street/strip car I try as hard as I can to use an extended tip plug for several reasons.

One, the extended tip is hanging out a bit further and it gets a bit more fuel on it to cool it at WOT.

You can (often but not always as this depends and several factors) run a heat range hotter with the extended tip. At WOT the plug is cooled by a bit more fuel and loafing around it runs a bit hotter.

You can (again usually but not always) run a couple of degrees less timing with the extended tip plug. It moves the plug further into the chamber.

And the C61YC has a full ground wire. It’s hard to do NA (but I’ve done it when I’ve screwed up) but the full length ground wire will start to melt so you have a better chance of seeing the wire start to deform. When it does you know you are about to eat a poop sandwich.

The C63CX plug has a shorter tip so it’s less likely to give issues at WOT but you need a bit more ignition to make them happy.

Because the plug is shorter you may need a couple of degrees more timing.

Because it’s not getting as much fuel on it, it will be hotter at WOT.

Don’t let the range numbers confuse you.

The 61 is colder than the 63 but it’s further in the chamber.

On the dyno I usually end up a range or two colder on plug because the dyno loads the engine differently. It’s like a jet boat kind of.

If I were you I’d start with the 61 and if that’s too cold go to the 63.

You used to be able to get a C63YC but I’m not sure they make them any more.

You can also see if the C63C is still available.

It blows that all these plugs are being eliminated.

 

[340six]

Something from this pile. What ever is on sale and screw cleaning um. Preferable NGK or Autolite. Even got some Snake oil left incase i need plugs for J Heads. They are all the same heat range 5 in NGK is a Champion 12 and same heat range in Autolite. All 3 are small 5/8 so fit in my aluminum and steel heads. Plus ya can loan some to Chevy guy's