What is the difference between and Champion X and the Champion A-25's?
The X's are a little nicer in that they can be taken apart into component pieces and rebuilt. The 25's are like a modern remake equivalent. They fit the hole and do the job but are not take-apart.
Here's a better answer from Royce Peterson in an older thread:
The Champion X plugs were assigned a new part number to match the system Champion was using for all their plugs about the beginning of WWII. That number was A25. So you will find new old stock Ford script Champion X plugs in boxes marked with the Ford part number, Champion X and A25 on the ends. You will find other plugs from the same period with all the same markings but without the Ford script.
Champion began finding ways to make the plugs cheaper to manufacture. Transitional changes eliminated first the brass top, then the blued parts were cad plated, even later the bases were made one piece so you could no longer take the plugs apart and clean them. Recent A25 plugs have stainless steel metal parts, eliminating the need for any plating.
There are perhaps 30 variations of the Champion X plug / A25 that I have seen for sale or own in my collection. There are variations in electrode diameter, electrode length, knurl nut design, porcelain shape, brass top or not, etc. There are variations with "Made in Canada" and "Fabrique en Fr." to add another variation multiplier. Take apart cad plated A25 plugs are found in Sears Roebuck packaging from the early 1960's like the ones Ted Dumas is describing.
I have been collecting the X plug variations and advertisements for years. It is amazing all the changes that have taken place in the X / A25 series. I have never seen any precise record of when exactly each change took place, and must base my guesses by period advertisements. You could write a sizeable book on the subject.
So no one plug works better than the other.
I believe generally speaking the older original Xs are better quality than the newer A-25s.
Can someone please tell me what are the best plugs to use with a Fronty R head? Thanks very much!
Ken that's a terrible head. No good plugs for it. I'll be glad to help you and trade you my stock low head for that, you'll be a lot happier.
I had been running Motorcraft F11 plugs for about four years and at some point, for some reason, decided that my engine would be happier if I treated it to a set of NOS Champion-X plugs. I also felt strongly about having the correct, historical appearance.
Well, it didn't work out. The engine ran just awful on the Champions, so the Motorcraft plugs went back in—and looked as wrong as a tiger eating a salad with extra tomatoes.
But hey, at least the engine was running nice and smooth, again.
Well, fortunately, Langs carries a special knurled thumb-nut that will fit the top of a Motorcraft spark plug and it sort of, maybe, kind of looks right if you squint just a little. True, no compromise ever got a standing ovation, but this is one I can live with. Maybe it'll work for you too.
I have Montgomery Wards brand in the car and they seems to do ok.
The modern 25 non-take apart, which I think have a different number now, the threaded part where you screw the nut on can come out real easy if you over tighten the nut and try to take the nut back off.
Motorcraft seem to do good also, the only problem I have seen is the crimp where the porcelain fits into the base develops leaks and you can see black blow by on the porcelain. Could just be the lot group that we happen to get.
John / Everyone - I have A25 plugs in my RAJO head. These are the same set of plugs my dad ran in the head back in the 1970s, and I'm sure before that (probably in the 60s). Cleaned them up and gapped them at .038" and they run great. Just my $0.02, YMMV.
Looks like personal experience/preference is the answer here. Thanks to all who responded.
I guess as long as it runs well it really doesn't matter what plug you use.
That's exactly correct, John. The trick is in determining which plug will do it.
I figured there was no other way to ascertain whether my really good engine had the potential to run really great until I tried the type of plug which, according to legend, is able to leap a 0.040 gap in a single bound and save Jimmy & Lois at the same time—the Mighty Champion-X.
But yeah, turned out it was only a legend.
Thanks for the offer Seth -- I wish all my friends were as generous as you!! I still don't know what plugs it's best to use!
These seem to work OK for me.
As Royce pointed out, there have been many versions over the years. The last here (#6) is the current one.