Correct spark plug for a 1921 Premier Touring Car??

[tomwallace]

I bought a 1921 Premier Touring Car a quite few months ago and I am just now getting time to get the car running.

I have been rewiring the car because the original wire was corroded and void of insulation.
We just replaced the spark plug wires with the correct period wire.

The car had a mix of 2 types of spark plugs. I got info from some source that the replacement plug would be an Autolite 3076. So I got a set and started to take out the old plugs. The old plugs had a lot of soot and looked burnt. So they definitely need replaced.

But the old plugs have a much longer throw than the new Autolites! I am afraid that the new plugs would not deliver the spark to the correct position in the cylinders. See a photo of the plugs below.

Any wisdom or suggestions would be appreciated,

Tom Wallace
Dayton, OH

[jrbartlett]

Was this car from Houston? If so I knew it in the 1960s.

[PFindlay]

Hi Tom, nice car.  My brother recently picked up a 1915 Premier.

 

According to my 1919 Dykes manual, the long plugs that were in your car are 7/8 - 18 plugs with a 1/2" extension.   The Autolite plug you bought is a 7/8-18 standard length.

 

Also according to Dykes, the 1919 Premier used 7/8-18 standard plugs.  Perhaps someone with a 1921 Dykes can confirm if that changed, but I doubt it.  You probably have the right plugs.

 

I use the long plugs in my Cadillac (Champion W18) , even though the correct plug is a standard length W14.  I believe it's a hotter plug, good for that oily, sooty combustion.  As long as there's room for the extra length you can probably use either.

 

Peter

 

[tomwallace]

No. This car came from Moorecroft, Wyoming.

 

I have all the history of the car since it was purchased as a used car in 1927.

 

Thanks

 

Tom Wallace

Dayton, OH

[Spinneyhill]

I have some very poor photos of some very old charts. The Premier is said to take a 7/8-18, what looks like manufacturers number JC-43. The picture is like this, so it is standard length.

  Unfortunately I don't know the year of the chart. But it appears to say the same as Dyke's, referenced above.

[cahartley]

These probably have TOO long a reach.

 

http://www.fme-cat.com/overlays/part-detail.aspx?brandId=CP&pNum=589&partType=Spark Plug 

 

 

You could modify the electrodes.

[tomwallace]

I got a set of Champion W18's yesterday. They look like they will work well.

 

Thanks all.

 

Tom Wallace

[Gary Haptonstall]

Tom, glad to see this car in good hands. This car was owned by my grandmother's uncle back in the day, then eventually restored by Dick Smith.Would love to chat about it with you. gary.haptonstall@gmail.com