What's up with todays plugs?

[dthx]

My 1976 parts list says to use Champion J4J plugs.
Are they still available?
And if not can I go to the auto parts store and get an alternate?.....
OR should I order something.....
Don't want to get a plug with the wrong heat range.
Any help would be appreciated.

 

[fhhuber]

Yes, Champion still makes the oddball plugs not called for by anything made since the 1930's.

Your auto parts store might have to special order if its really strange. I'm not familiar with the J4J, but I don't think its anywhere near as obnoxious as some I have needed.

 

[samuel joff]

Not sure auto parts how long serve. It will much better and appreciate for him to find out the original one like Champion J4J plugs anyhow.

 

[F_R]

J4J is now called J4C. Same heat range etc., except the ground electrode extends all the way across the center electrode. The J4J extends only half way across. You can file the "C" back to be like the "J" if you want to. However, the J4C is kind of hard to find. They probably will want to sell you a J6C, a hotter heat range.

 

[emdsapmgr]

Bombardier still stocks the J4J plugs for their dealers. 502193 is the p/n.

 

[60sboater]

I bought some J4Js last year for my '72 25hp Johnson. I think I got them at O'Reilly auto parts.

 

[dthx]

I went to Oreilly's and they didnt have the j4j but they gave me an AC Delco R45.....said that it was an equal......how can I be sure.....?
Do all of you recommend the actual J4J.......
I think it's very cool to have a 1976 engine that cranks up at the dock and runs great......it gets very little service....just down the river to catfish and up the river to the camp to fry em up...
I dont want to damage my engine.....guess I should just go ahead and order the J4J and forget about it.

 

[82rude]

r-45 is equal to j6c .j4c is the direct replacement for j4j which is no longer made .Doesn't mean you cant get just no longer made.Where I am j4c are easily available as are j6c .I use or have used j4c in my older j/e engines with zero issues .Do not be surprised if the plugs you order from brp come in as j4c.Theres no reason not to use the j4c as that's the replacement for the now defunct j4j.Its very likely that there is still j4j around as the current stock would have to be used up but once the last one is sold that's it .

 

[dthx]

Thank you for taking the time for that reply....It helps.

 

[samuel joff]

J4J is now called J4C. Same heat range etc., except the ground electrode extends all the way across the center electrode. The J4J extends only half way across. You can file the "C" back to be like the "J" if you want to. However, the J4C is kind of hard to find. They probably will want to sell you a J6C, a hotter heat range.

Glad to know more about this J4J here. And name have been changed which I didn't know. Thanks for your efforts.

 

[F_R]

I went to Oreilly's and they didnt have the j4j but they gave me an AC Delco R45.....said that it was an equal......how can I be sure.....?
Do all of you recommend the actual J4J.......
I think it's very cool to have a 1976 engine that cranks up at the dock and runs great......it gets very little service....just down the river to catfish and up the river to the camp to fry em up...
I dont want to damage my engine.....guess I should just go ahead and order the J4J and forget about it.

Dagnabbit, that shows what happens when you believe plug charts. They must be written by idiots that figure if it fits the hole, it will work. The AC equvilant to a J4J is an M42K. I happen to have a bunch of them out in my shop. But I think they probably are NLA so they'll give you anything. FYI, an R45 is more equal to a J8 in heat range, and is also a resistor plug. NOT what you want in most outboards.

 

[Crosbyman]

if the heat range is the same in another brand.....does it matter or is it just nostalgia ??

http://www.sparkplug-crossreference.com/convert/CHAMP_PN/J4J

 

[F_R]

I will withhold comment on the NKG brand, because I am not familiar with their numbering system. But just for general information, plugs are classified according to some basic factors

Thread diameter & pitch
Thread length
Seat type
Heat range. This refers to how well it dissipates heat from the plug tip to the cylinder head.
Special design features. Q means inductive resistor, R means resistive resistor, etc, etc
A potfull of other special qualities such as electrode design, material, rustproofing, and more.

Plug mfrs and engine mfrs are constantly working together to design whatever new engines need or require, and new numbers appear frequently. Therefor it is quite understandable that old designs are either obsoleted or replaced with something that "will work". Think how huge their inventory would be if they stocked all designs ever made.