Champion c4 plugs

3

31ster

Senior Member
Good evening. I bought these plugs today along with some others. Can anyone tell me if they are valuable or just good plugs to run. Also what the specific application would be. There are ten plugs in the box Thanks ian
 

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Someone must have found a tomb with Champion plugs in cosmoline. I bought a box of them also this summer for $1 each. I'm not sure what they fit, but any plugs sealed like that have to be worth what I paid just for a shelf display.
 
Champion C 4 spark plugs are very good spark plugs and run clean. C4 plugs are discontinued and are not listed in the Champion heat range chart. I believe and have been told that the C4 has the same range as the Champion W 18 which is 7 . I think that the C4 was used in the model B four cylinder engines as well as some other applications. These spark plugs are two piece and the brass top version looks a lot like the 3X plugs and at first glance will fool some . There were at least 3 versions of this plug . The first version was blued or dark colored base with a brass cap at the top. The second version didn't have the brass cap and the third version had a silver colored base and no brass cap. I think that the last version was discontinued in the very early sixties and replaced with the C16C that wasn't a two piece plug or the exact same heat range. I've paid as much as $100.00 for 5 new old stock C4 plugs. I have also bought new old stock C 4 Champion plugs in boxes of 10 . The ones that I've found had a note recommending proper gap for use in the model A & B engines. I've still got the first set that I bought in 1960 with the silver base. If I was you and needed spark plugs, I would run them in my model A .
 
Thanks for the replies and info. I bought the box and four individual plugs. I will prob put the box on the self and use the others in my car. It amazes me how much care and obvious pride went into a spark plug. I was looking at one of them and it still has finger prints in the wax wrapper
 
The C-4 Champion plug was introduced in 1932 for the first year of the V8 engine. For that one year of 1932 the V8 engine used a spark plug of the same thread pattern as the Model A and Model B. (Reference 1932 Service Bulletins) In 1933 the V8 engine used a different thread pattern which continued for the following years. Over the years following 1932 the C-4 gradually fell into use as a replacement plug the the Model A and Model B. There is a slight difference in the heat range from the 3X per the Service Bulletins.
 
Like Tom I also bought a box this year ( fall. ).There seemed to be a surplus of them at Hershey. The going price seemed to be 10 to $ 15 a box. I ended up paying 15 and then I started to see them cheaper. I installed them in my 29 pickup and they run fine. Wayne
 
1930 coupe said:
When the C-4 first came out Ford said do NOT use them in a four cylinder because they were too cold. In later years after the 3-X went out of production, parts stores started telling people to use C-4 plugs in four cylinder engines.
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Not sure where you get your copied info, maybe from one of the national mags. It hasn't been that long since I was flamed in an attempt to discredit me about the Champion W18 spark plugs . It was said that the W 16 Y had a longer tip-electrode and was hotter than the W 18 , even though the heat range chart stated that the W18 had a heat range of 7 while the W 16Y had a heat range of only 6. Now its being said by somebody that the Champion C 4 is colder than the Champion 3 X because the C 4 has a longer tip electrode than the 3X. I guess it depends on which way that the wind blows and how tip length will be used in an attempt to discredit or say which spark plug is the hottest . Tip length doesn't come into play as far as heat range goes in some cases until a certain RPM is reached. Anybody that has run Champion W 18 spark plugs knows that they are hotter and run cleaner than the colder W 16 Y at the speeds that most model a are used. Same goes for the Champion C 4 . It doesn't seem to matter whether I talk about hotter coils or hotter spark plugs, certain individuals here will try to discredit whatever I say. I'm not trying to sell spark plugs or services here . I do have over 50 years of experience running all kinds of spark plugs in model A Fords.
 
[QUOTE=Purdy Swoft;985616]Not sure where you get your copied info, maybe from one of the national mags. It hasn't been that long since I was flamed in an attempt to discredit me about the Champion W18 spark plugs . It was said that the W 16 Y had a longer tip-electrode and was hotter than the W 18 , even though the heat range chart stated that the W18 had a heat range of 7 while the W 16Y had a heat range of only 6. Now its being said by somebody that the Champion C 4 is colder than the Champion 3 X because the C 4 has a longer tip electrode than the 3X. I guess it depends on which way that the wind blows and how tip length will be used in an attempt to discredit or say which spark plug is the hottest . Tip length doesn't come into play as far as heat range goes in some cases until a certain RPM is reached. Anybody that has run Champion W 18 spark plugs knows that they are hotter and run cleaner than the colder W 16 Y at the speeds that most model a are used. Same goes for the Champion C 4 . It doesn't seem to matter whether I talk about hotter coils or hotter spark plugs, certain individuals here will try to discredit whatever I say. I'm not trying to sell spark plugs or services here . I do have over 50 years of experience running all kinds of spark plugs in model A Fords.[/QUOTE]

Not to worry Purdy. When you speak people on the Barn listen because we know you have outstanding knowledge and you don't use the key board unless you know what you are talking about. ! In other words " you da man " !
Wayne
 
I have seen at least 5 versions of the C-4 plug made over the years of production and have to wonder about the possibility that the heat range varied slightly from one version to another. I think the Ford directive to not run them in a Model A probably had something to do with the low octane gas available at the time. They sure run well with my 5.5 Snyder head.
 
They also run clean with Brumfield heads, F3 heads and stock 4.22 heads. I've personally never seen it said that the Champion C 4 sparkplugs were colder. I read somewhere that Henry was concerned that the higher compression of the 4.6 , C head might blow out the spark and that a smaller gap would be prefered. I can't remember where I read this..There were instructions with some of my C4 plugs that recommended a gap of .032 when used with model A and model B engines. This indicates that they were used as a replacement for the Champion 3 X plugs There is no referance to the heat range of the 3X , C 4 , or the C 16 C spark plugs .
 
Ford Service Bulletin of August 1932, "The B-12405 Spark Plug used on the Improved 4-Cylinder Engine, and for service requirements on the "A" engine, is what is commonly designated as a moderately hot plug, and is exactly suited to the requirements of the Ford 4-Cylinder Engines which are of medium compression and comparatively cold running. Such an engine requires this type plug to prevent the plugs from fouling."

That's a big run-on sentence! I went through my library and the Big Orange Book of 1948, and the Big Green Book of 1950 indicate that the service plug for the Models "A" & "B" engines eventually became the 18-12405 which was the 1932 V8 plug. So I can see a trail that indicates:
A-12405 Spark Plug is a Champion 3X;
B-12405 was A-12405, so the Model "B" engine used the Champion 3X;
Somewhere along the way, the post WW2 spark plug for the Models "A" & "B" became the 18-12405. What brand & number is the 18-12405, and where is the answer documented?
Ironically, there is a caution in the 1932 service bulletin not to use the 18-12405 V8 Spark Plug in the 4-cylinder engines because the V8 plug is too cold and it will foul.

 
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Ford had their own part numbers for light bulbs too and they didn't have a cross reference that I know of either. If they did, I'd sure like to see it. Champion and other related companies changed part numbers every time they changed designs and still do. Champion must have made a half dozen designs that fit in the early Ford 7/8"X 18 thread types. Then there were the others like Edison/Splitdorf and more that didn't survive the depression or were bought out.
 
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