Model T Sparkplugs
 

Hello,


Where can I obtain a list of what spark plugs can be used in a 1923 Model T? I have a few boxes, bags and buckets of brand new plugs, some still in the boxes that I am hoping will work in my speedster. Some of them Splitdorf, Firestone, Wards, Champion, Aldor, Luthy, Stitt, Fyrac, Fan Flame, etc. I did find some Champion X, and aren't those what was originally used? I think what is in the car right now are A-25(?) Champions, and I would like to change them out because they seem to be somewhat fouled.


Thank you in advance for the assistance.


Jeff

Re: Model T Sparkplugs
 

You have a perfect chance to try different plugs and give us a report on how they all worked in your car. Fouling is not only caused by the plug so check other things such a carb and timing.

Re: Model T Sparkplugs
 

So will any plug work as long as it is 1/2" plug thread and not deeper than the model X into the head? That is why I am looking for a list of acceptable plugs, if there is such a thing.


The fouling could be operator error on my part because I am just learning to drive this car.



Thank you,


Jeff

Re: Model T Sparkplugs
 

Yes to the 1/2 thread plugs and deeper part. No there is no list. Like oil there are many opinions of what works well in someones car. What works well for me does not mean it will work well for you.

Fouling could be from running too rich, but could be other things.

Re: Model T Sparkplugs
 

Pretty much any will work, i use A-25 as that's often all i can find.
The good thing about those plugs in champion X and A25 are resistant to heat and big enough you can clean the tips with a propane or MAPP gas torch if you're careful.

Don't rub them with a wire brush though. I've done that & the metal particles stay embedded a long time.

Re: Model T Sparkplugs
 

What about using a rag or paper towel? I have never cleaned a plug with a torch. Do you just stick the flame down in the plug end?


Thank you,


Jeff

Re: Model T Sparkplugs
 

After a log of digging it appears that Autolite 3095 & Motorcraft F11 are possibly direct replacements. Can anyone please confirm?


Thank you,


Jeff

Re: Model T Sparkplugs
 

Yes, they are.

Re: Model T Sparkplugs
 

Re: Model T Sparkplugs
 

Hi Jeff do you have in your treasure chest the out part of the 2 piece champion X - i have four new NOS cores I picked in my travels I would like to use..
Thanks Stuart

Re: Model T Sparkplugs
 

Unless you have sealing washers with the cores or can find bodies with good ones in them..well lets just say there is more to putting plugs together then just installing new cores.

Re: Model T Sparkplugs
 

A rag or paper towel will remove loose carbon. Some people have access to chemicals to loosen carbon. I have never tried oven cleaner but it might help, or not.

I put the flame down the end of the plug.

Re: Model T Sparkplugs
 

The Autolite 3095 and Champion F11 plugs are 1/2" pipe thread spark plugs made to service a lot of older applications that use such a spark plug. They are much colder heat range than Champion X or other period spark plugs. So they foul much more easily in a Model T. A better approach is to clean and re - use original spark plugs from the era. They will last a long time between cleanings. In my experience they tend to never foul so long as there is nothing major wrong with the engine.


I find that chemicals designed for cleaning guns work very well on spark plugs for removing carbon and soot / fuel deposits. Here is a little write up:
https://modeltfordfix.com/cleaning-t...rk-plug-t1386/

Re: Model T Sparkplugs
 

I do not, sorry.

Re: Model T Sparkplugs
 

I have had most of this from when I was a kid and would go on "rusty iron" trips with my dad to buy stuff and drag it home. Just like dad, I really don't get rid of anything, and my boys like this stuff also, so they can fight over it when I'm gone someday. I'm almost 50, so I hope to enjoy it another 30 years or so... lol.

Re: Model T Sparkplugs
 

What makes the heat range lower on a spark plug? Can something be added in between the wire and plug to boost the heat range on new plugs? I would rather leave these plugs in my collection and use new plugs and have to change them out once a year verses using these nos plugs.



Thank you.

Re: Model T Sparkplugs
 

Heat range is mostly about how fast a plug dissipates heat. The faster it does that then the colder the plug is. It is controlled by the design of the ceramic insulator that is inside the combustion chamber. The more insulation, the smaller the space is between the insulator and the inner barrel of the threaded portion of the plug.

A hotter plug will have more space in there and less insulator around the electrode. The hotter plug heats up faster and will burn out more combustion bi-products than a colder plug will. If a plug fouls more than it should, a hotter plug would be in order to decrease fouling. The problem is, I don't know if there are any hotter ones made in this day and age. A person has to find an old Champion 30 or 31 set that still works or live with what they have.

Re: Model T Sparkplugs
 

Champion X

Re: Model T Sparkplugs
 

I think the Champion X spark plugs made today are closer to the old Champion part number 25 and they are likely cooler than the old part number 30. Now days they just have the one plug.

Re: Model T Sparkplugs
 

Do you have any evidence to support your opinion? I use X in the T, and 3X in my A and they run better than other plugs I have used.