Champion J11Y/Mopar P-34P spark plugs

[Mopars & Missiles]

Note: recommended not absolute.

I believe that is EXACTLY what I said. "Factory Recommended" Nothing about "absolute". You are entitled to your opinion, just like everyone else. We all know what opinions are like and yours is no different.

 

[lewtot184]

1968 440. FSM says J11Y or P-34P for 383 and 440. Interestingly, it also says if those aren't available, then the J10Y is a suitable replacement.


Thanks!

Now, do I use them or hang onto them?

i have a box of mopar plugs marked 34p which are actually j10y's. the j10y was the performance plug for street wedges until the j11y which I believe was introduced in '67 model year.

 

[RJRENTON]

Gentlemen,
Being a self proclaimed "expert" on spark plugs for the Mopar wedge engine (B=350,361,383,400 cubic inch & RB=413,436W,440 cubic inch) I concur with Lewtot184, the Champion J-11Y and the Mopar P34P are the same plug, both being manufactured by Champion Spark Plug Co., in Toledo Ohio.
There is considerable differences between the J-9Y, J-10Y, J-11Y, J-12Y, J-13Y, J-14Y, etc. (and the resistor equilivants, designated by the R, Q, O, X prefix letters) and later designs with the copper cored ("C" designation) center electrode.
Other factors influencing the heat range is diameter of the center electrode, alloy of the center electrode, exposed length of the center electrode, length of center electrode's insulator from the tip to the internal compression gasket, density of center electrode's insulator.
Different engines used different heat ranges, depending on application....ie, 413 & 426 Max Wedge engines used J-9Y plugs (due to the 12.5:1 compression ratio) compared to regular 413 & 426 street wedge engine. The 361, 383, 400 2bbl engines used J-13Y or J-14Y due to lower compression and mild cams. The 383 HP & 440 HP engines used J-11Y plugs because of higher compression ratios and more radical cams.
Spark advance and static timing are also major influences to spark plug heat range as well as emission requirements.
Which plugs are best??? The Autolite vs NGK vs E3 vs AC vs ???, debate will continue ad infinitum....each proponent will have their own opinions and preferences.
Personally, I use Champion UJ-11G or HO-8A plugs in my 1970 Plymouth GTX Six Barrel, RS23V0A******* with 11.0:1 pistons , Crane cam, 4.10 Dana gears, Prestolite dual point distributor. This is what works for me.
Bob Renton

 

[moparnation74]

What was the OP's original question?..........lol.....

 

[RJRENTON]

Is the J11Y supposed to be the factory plug on big blocks (specifically, 440's)?
I went looking for some after I just installed a set of the only plugs the parts store had in stock recently (NGK). Needless to say, not impressed with those.
I then snagged up on an original set of Mopar 26422913 P-34P spark plugs still in the box for a pretty good price I think.

Were these the original plugs in our big blocks? Are they rare to find these days?
I paid $20 for the set of 8. How'd I do?

The $20 price was decent.....search eBay for either vintage mopar spark plugs or champion J-11Y or P34P or by the part number.
One day last fall, I was surfing eBay specifically Mopar P34P spark plugs and found a person in Texas who had lot of NOS Mopar plugs sale. The price for 8 NOS plugs was $18.00. I corresponded with him and I purchased 16 sets @ $11.50 / set including shipping. I sold 8 sets to a Mopar friend in LV Nevada for cost; I'm keeping the balance for my own use.
FYI....shop around....make an low ball offer....the worst they can do is decline the offer.....but....maybe you'll get lucky.
Bob Renton

 

[moparedtn]

What was the OP's original question?..........lol.....

Yeah, the original questions keep being sort of ignored here.
Question 1: Are the J11Y's OE for the big blocks? Answer: Some, yes, including mine. My own FSM also agrees.

Question 2: Are these plugs rare? I'll answer that one as well. J11Y's are out there for sale somewhat. From what I've seen in digging around, they go for about double what I paid - but here's the kicker:
Mine are the equivalent Mopar-marked originals still in original packaging.
I bought these to use, but I'm having second thoughts now because I haven't found any more of them online so far. At all.

Question 3: Did I get a good deal on these? Most assuredly, again based on what's out there for sale right now.

Question 4 (added later in the conversation): Do I hoard these or install them?
Jury is still out on that one, since nobody has offered any opinion on that one at all.

Guys, thanks for all the usual opinions on folks' favorite brands of plugs.
Truth is, I didn't ask for that because, well, I have my own opinions on that as well.

 

[moparedtn]

The $20 price was decent.....search eBay for either vintage mopar spark plugs or champion J-11Y or P34P or by the part number.
One day last fall, I was surfing eBay specifically Mopar P34P spark plugs and found a person in Texas who had lot of NOS Mopar plugs sale. The price for 8 NOS plugs was $18.00. I corresponded with him and I purchased 16 sets @ $11.50 / set including shipping. I sold 8 sets to a Mopar friend in LV Nevada for cost; I'm keeping the balance for my own use.
FYI....shop around....make an low ball offer....the worst they can do is decline the offer.....but....maybe you'll get lucky.
Bob Renton

See post #11. Ain't my first rodeo on ePay.

 

[moparnation74]

Yeah, the original questions keep being sort of ignored here.
Question 1: Are the J11Y's OE for the big blocks? Answer: Some, yes, including mine. My own FSM also agrees.

Question 2: Are these plugs rare? I'll answer that one as well. J11Y's are out there for sale somewhat. From what I've seen in digging around, they go for about double what I paid - but here's the kicker:
Mine are the equivalent Mopar-marked originals still in original packaging.
I bought these to use, but I'm having second thoughts now because I haven't found any more of them online so far. At all.

Question 3: Did I get a good deal on these? Most assuredly, again based on what's out there for sale right now.

Question 4 (added later in the conversation): Do I hoard these or install them?
Jury is still out on that one, since nobody has offered any opinion on that one at all.

Guys, thanks for all the usual opinions on folks' favorite brands of plugs.
Truth is, I didn't ask for that because, well, I have my own opinions on that as well.

Missed your question 4 and I see now where it was.......They are readily available to find in relation to the correct J11y's......I would use them.....Keep in mind the OE guys would never consider the "mopar" brand.....Trust me I am not knocking what you have.....I have those as well in sets and some with points included.......They are a cool novelty item.....

If you need a correct set of J11y's in the future shoot me a PM anytime.......I will hook you up with a set better than what you can find but will be more cost than the Mopar plugs, lol....Now that is the set you may want to stash aside

 

[Ranger16]

As long as we are on the subject of spark plugs, here is a question that I have long pondered.
Given the fact that due to the manifold configuration makes plug accessibility a PITA (ESPECIALLY the #3 with P/S), and given the fact that platinum tipped plugs don't erode and have a MUCH longer life, is there a platinum tipped equivalent to the J11Y? It would seem to me that an equivalent in heat range/length/resistance, etc would be the way to go (if there is such an animal), or is that simply wishful thinking? What say you experts?

 

[moparedtn]

Missed your question 4 and I see now where it was.......They are readily available to find in relation to the correct J11y's......I would use them.....Keep in mind the OE guys would never consider the "mopar" brand.....Trust me I am not knocking what you have.....I have those as well in sets and some with points included.......They are a cool novelty item.....

If you need a correct set of J11y's in the future shoot me a PM anytime.......I will hook you up with a set better than what you can find but will be more cost than the Mopar plugs, lol....Now that is the set you may want to stash aside

I appreciate the offer and the opinion.
What's out there available (at least in my research lately) shows the opposite to be true, however - original J11Y's are out there available (for a price, of course) but the 2642913/P-34P Mopar plugs just aren't.
Yes, they're the same plug we know, just dolled up differently - even so, do any of the "concourse" type restorers care what plugs they use?

 

[moparedtn]

As long as we are on the subject of spark plugs, here is a question that I have long pondered.
Given the fact that due to the manifold configuration makes plug accessibility a PITA (ESPECIALLY the #3 with P/S), and given the fact that platinum tipped plugs don't erode and have a MUCH longer life, is there a platinum tipped equivalent to the J11Y? It would seem to me that an equivalent in heat range/length/resistance, etc would be the way to go (if there is such an animal), or is that simply wishful thinking? What say you experts?

I remember the first time I bought a set of platinum plugs, back when I got my '04 Ram (hemi - 16 of the little bastards!).
The factory Champions Mopar was using in the late model hemi 5.7 is a regular ol' copper plug and they recommended replacement at 30k miles.
Oy.
Naturally, folks wanted to install a plug that would last longer than that, especially since other makers were bragging about 100k mile intervals on their plugs.
I jumped on the platinum/exotic plug bandwagon and slapped a set in there.
Truck ran noticeably poorer and fuel economy went in the crapper.
Come to find out, all the computer controls and programming and such were actually dialed in to using the regular old plugs and didn't work as well with better plugs.
I slapped another set of the exact Champions the factory built them with and all was well again.
Haven't deviated from that since, 15 years later. Truck still runs like a raped ape, even without an aftermarket tune.
Still HATE changing the plugs though. Absolute pain in the *** on the trucks, although in the '12 Charger it's a breeze.

Moral of the story:
Sometimes more modern isn't better.
I wonder if platinums would work better in our ancient engines, though?

 

[moparnation74]

I appreciate the offer and the opinion.
What's out there available (at least in my research lately) shows the opposite to be true, however - original J11Y's are out there available (for a price, of course) but the 2642913/P-34P Mopar plugs just aren't.
Yes, they're the same plug we know, just dolled up differently - even so, do any of the "concourse" type restorers care what plugs they use?

Yes the concourse do and if judged those plugs will get dinged.......same goes for oil filters, fuel pumps,air filters etc.....have to have the right stuff....

Just because they are not readably available does not mean they are in high demand.......

The price you got then for was a great price in the end and that is what matters here....

 

[lewtot184]

As long as we are on the subject of spark plugs, here is a question that I have long pondered.
Given the fact that due to the manifold configuration makes plug accessibility a PITA (ESPECIALLY the #3 with P/S), and given the fact that platinum tipped plugs don't erode and have a MUCH longer life, is there a platinum tipped equivalent to the J11Y? It would seem to me that an equivalent in heat range/length/resistance, etc would be the way to go (if there is such an animal), or is that simply wishful thinking? What say you experts?

there isn't anything equivalent to a j11y in my opinion. an autolite ap85 is close and with a platinum tip.

 

[WileE]

As long as we are on the subject of spark plugs, here is a question that I have long pondered.
Given the fact that due to the manifold configuration makes plug accessibility a PITA (ESPECIALLY the #3 with P/S), and given the fact that platinum tipped plugs don't erode and have a MUCH longer life, is there a platinum tipped equivalent to the J11Y? It would seem to me that an equivalent in heat range/length/resistance, etc would be the way to go (if there is such an animal), or is that simply wishful thinking? What say you experts?

A good question, but from where I sit, does longevity/frequency of plug changes come into play with how we use these classic cars ? I used to do these routinely back when these cars were due for their tune ups. Compared to some of today's disasters, most of these cars were pretty easy to do plugs. The key was: the right tool and the right technique.

 

[moparedtn]

Yes the concourse do and if judged those plugs will get dinged.......same goes for oil filters, fuel pumps,air filters etc.....have to have the right stuff....
Just because they are not readably available does not mean they are in high demand.......
The price you got then for was a great price in the end and that is what matters here....

Wait a sec. According to my FSM, the P-34P's or Champion J-11Y are the "specified" plugs.
Are you telling me the Champion was the factory-installed one and the Mopar ones are the "aftermarket" ones here?

 

[moparnation74]

Wait a sec. According to my FSM, the P-34P's or Champion J-11Y are the "specified" plugs.
Are you telling me the Champion was the factory-installed one and the Mopar ones are the "aftermarket" ones here?

The ones you have are the OTC mopar part....

The chanpions were the factory line part....

Line parts are not always the same exactness as the OTC part......that why you have to know or know someone who can differentiate them.....you have to be careful when you buyNOS parts of any type....there are subtle variations.....

I have been involved in the OE world for over 25 years....their are very very few cars that can meet a 90 plus correct scale.....it is more than just plugs.....

So those Mopar stamped plugsare incorrect if your trying to be an OE coreeco car.....

If we don't preserve what is correct than people can think they can put on whatever by a part number cross reference.....

 

[moparedtn]

The ones you have are the OTC mopar part....
The chanpions were the factory line part....
Line parts are not always the same exactness as the OTC part......that why you have to know or know someone who can differentiate them.....you have to be careful when you buyNOS parts of any type....there are subtle variations.....
I have been involved in the OE world for over 25 years....their are very very few cars that can meet a 90 plus correct scale.....it is more than just plugs.....
So those Mopar stamped plugsare incorrect if your trying to be an OE coreeco car.....
If we don't preserve what is correct than people can think they can put on whatever by a part number cross reference.....

Got ya, thanks.
Learning all sorts of minutiae about these plugs. These are the "first gen" plugs, anyways, as Mopar superseded the part number later on to
3420752.
It's also interesting that the part number I have superseded a bunch of numbers that came before it in Mopar world:
1889521, 2095247, 2098334 & 2098337
Not only that, but Mopar sold plugs marked Champion J-11Y in combined Mopar & Champion packaging showing the original Mopar part number:

 

[moparnation74]

Got ya, thanks.
Learning all sorts of minutiae about these plugs. These are the "first gen" plugs, anyways, as Mopar superseded the part number later on to
3420752.
It's also interesting that the part number I have superseded a bunch of numbers that came before it in Mopar world:
1889521, 2095247, 2098334 & 2098337
Not only that, but Mopar sold plugs marked Champion J-11Y in combined Mopar & Champion packaging showing the original Mopar part number:
View attachment 608399

There were a lot of variations.......The correct j11y for 69 is a champion only plug....and the champion j11y stamp is an brownish color.....Also look at the plating on the bases between the two.....The colors of the stampings.....

So as you can see through your research. When you start breaking things down to the fine details......Finding the correct parts is very very difficult.....

Try to find an original assembly line oil filter that is correct for that model year.......When you do you may want to bend over first.....

Better than that, try to find a correct trunk seal with the pn moulded on it......

The list goes on.......

I enjoy the preservation of history in the relation to these machines.........

 

[moparedtn]

That's neat and all....but mine is a '68.

 

[moparnation74]

That's neat and all....but mine is a '68.

It is the same.....68/69......just a different pn.....but the look is the same and was the same for several years.....

How neat is that....lol....