A couple of days ago I was going to do my shopping by roadster, but the car was acting gutless. So I left it home and took the modern car. Yesterday I got around to investigating.I found that the #3 plug had a broken insulator rattling around loose. The insulator in #4 was loose also, but wasn't broken. Naturally, both had plenty of soot blown all over them. When I looked inside the two plugs, I found that #3 had the original type washers, and #4 had one of the copper crush washers I've been trying out.
This shows three plugs with insulators that have broken in the last year or so, and a new X plug I bought not to use, but to compare with the originals. A few weeks ago a Model T friend kindly sent me a gift of the current style washers which are shown on the right. At the other end are some of the copper crush gaskets I've been trying out.
So here's what I have in the car now. #1 is a "brass hat" plug with modern washers above and below the insulator. #2 is a take-apart plug with original washers. #3 is a brass hat with two moderns, and #4 is a take-apart with two moderns. I'll see how these hold up.
All are gapped as close to .030" as I could get them. I think that's correct, but I've seen different opinions on that.
Just a dumb question but could the overheating with the spark retarded caused this?? Bud still in Wheeler,Mi.
Maybe not so dumb, Bud. I suspect it could have.
There can be other factors. Over heating is just one factor to consider, this associated with a lean mixture being run over time. Not to mention that there are two placed to tighten the plug. One is at the base where it is to be tightened, and at the top where the plug goes together. There is also the possibility of quality control. The plug may be defective with a hair line crack from the time it left the factory.
A spark too advanced would be more likely to cause the problem. But I personally think it is the age of the spark plugs and perhaps strain on porcelon then the plugs were last assembled which caused the problem.
I think there was a reason smooth sides were stopped being made.Bud.
We recently discussed this issue. Early X plugs were before the 775 standard was invented. If you wanted Champion brand plugs that would not break you'd buy the more expensive "Heavy Stone" variants.
(Message edited by m2m on September 10, 2015)
Ford specified they were supposed to be gapped at 1/32 of an inch.
FYI Steve, your first pic is about 20% too wide to fit on my computer screen without scrolling. A minor inconvenience, to be sure, but though you should know in case it looks OK on your screen.
So you are zippy doing along and develop a miss. What to do? To check for plug gap at 1/32 of an inch just reach into your pocket and take out a worn dime. Exactly 1/32. (Motor Age, 15 February 1912).
Looks like they cracked because the gaskets don't fit right. Those soft copper washers might work better.
Re the 775 insulators, this was the designator for the formulation the Frenchtown Porcelain company used in manufacturing spark plug insulators. They were a very prolific producer, making hundreds of different brand insulators for different companies, including even some small town garages. Not too long ago some of our Spark Plug collectors began digging at the site of the old factory and uncovered hundreds of different brand factory seconds that were tossed out. You'll see them often on ebay. The Frenchtown Porcelain company had no relationship to Champion.
Until 1915/15 Champion produced their own insulators but at that time they purchased the Jeffery DeWitt Spark Plug Company, and along with it, the rights to mine Silliminite, which was a superior insulating material. That's about the time the famous Champion "brass hat" style of plug began to appear as it was a Jeffery DeWitt feature that Champion adopted. I don't know what year the catalog page shown above is but suspect it pre-dates the 1915/16 introduction of the Champion Silliminite insulators.
The Champion (or any other) plug often broke because the packing (or gland) nut was over-tightened. If you ever need to cut a piece of glass, a broken spark plug insulator will do nicely. That stuff is tough!
Thanks for the that useful info.
I guess this must be the ebay seller:
He's doing really well!
They are all from the same guys who have been shoveling them out of the ground for several years now. Some rare stuff has turned up but the problem is people have been making plugs with them by using the steel parts from Champion and other common brands. Been collecting plugs for over 40 years now and always look forward to Hershey as new stuff turns up all the time.
Apparently Champion produced both kinds of plugs for several years if brass hats were introduced in 1915. Their advertising shows take-apart plugs into the twenties.
I could be wrong, but I think brass hat Champions came later than 1915.
The ad above from 1921 is interesting...I would have thought "Heavy Stone" plugs would be long gone by the 1920s. Perhaps they're clearing out old stock? The discounts shown point to that.
There were at least several type of X plugs made. To add to the confusion other Champion plugs could be used on a Fords such as "Heavy Stone", #30, #31, #33 and all these came in at least a couple of different variants!
And I've seen NOS #30 with "Made in Canada" on them.
There are some NOS Silliminite #31 on ebay now:
If you can buy the 10 for $200 that's not a bad buy. That's cheaper than the new X plugs.
Champion continued to make a big deal about Sillimanite through the 1930's. This is a 1934 fair exhibit that toured for several years:
There is no clear-cut "ending" date for the Champion X with straight sides as there were thousands of then in inventory worldwide long after the newer style brass hat plug was introduced. War surplus increased the stocks of old style X plugs tremendously as well, so they were indeed available long after 1915.
Rip was built in late 1917 and still has its original straight side Champion plugs. Champion straight side plugs were original equipment in Model T's at least through 1921 from what I can determine, perhaps later as stocks were used up at the various factories.
So, Steve, what's the story on your latest #3 plug misfire issue?
Here's the latest. After being busy with other things recently, I drove the roadster when I went to town yesterday. All was fine until I heard the telltale tick tick tick, and the lack of power told me I was running on three cylinders. I stopped in the shade of a big tree and checked the plugs. The collar was loose and the insulator was jiggly on #3.
That was a common brass hat X with modern washers. I would have just tightened the collar and gone about my business, but I found this strange development.
The electrode and insulator are recessed so far up into the plug that the gap is more like ten dimes than one. I have no clue how this happened. Fortunately I was carrying spares. The other three plugs were OK.
Do you think it's still in the engine?? Bud in Wheeler,Mi.
Looks like the center electrode broke off and fell in.
I agree with Royce, that looks like trouble! If you're lucky it broke up into small enough pieces to make it past the exhaust valve and out the exhaust pipe.
Do you have access to a borescope to see if any pieces are still left in the cylinder and if the top of the piston has any impact marks on it?
Steve, I see from your blog that you've been working on your coils with a borrowed ECCT, do you have an update on that one plug that looked like it had the center electrode broken off?
I'm still working on the coils. I'll report on that later.
All I can report on the plug with the shortened electrode (#3 with modern washers) is that I looked through the plug hole into the chamber and didn't see any debris, and that I replaced it with another plug.
I'll also mention my $9 experiment. I bought a set of Autolite 3095 plugs to see how they are. I haven't done enough driving with them to have any opinion yet.