Announcement

Collapse

Get more Tips, Specs and Technical Data!

Did you know... this Forum is a service of the Studebaker Drivers Club? For more technical tips, specifications, history and tech data, visit the Tech Tips page at the SDC Homepage: www.studebakerdriversclub.com/tips.asp
See more
See less

Spark Plug dimensions

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Spark Plug dimensions

    I am in the process of changing Champion plugs in my newly-rebuilt 259 from H-12 to RH-18Y; I'm experiencing fouling and radio interference. However, I notice that the 18's will extend into the firing chamber about 1/4" further than the 12's did, due to the projected nose core. I have visions of destroying my piston heads--any cause for concern here?



    51 Commander State Sedan
    Butler PA

    51 Commander State Sedan
    Butler PA

  • #2
    For sure you don't want the threaded portion extending any further into the combustion chamber. The plug will screw in just fine and even though nothing may get in the way of anything important, carbon will build up in the exposed threads and you'll never be able to unscrew it.

    As far as the porcelian part sticking out further, that's because the 18 is a hotter plug than the 12.

    Comment


    • #3
      Yes and no. The spark plug is a long way from the piston, so you don't have to worry about that. I am not familiar with the plugs you are using, but you need to get the thread length correct. If the threads extend into the combustion chamber they will get carbon buildup on them. This will make them very hard to remove. Likewise if the threads are too short carbon will buildup in the head. If it is just the ground strap that is longer or shorter I wouldn't worry too much.

      David

      Comment


      • #4
        H18Y was a factory specified plug for some years of 259s. You are right to be concerned in general, but in this instance you don't have a problem, use them and be happy.

        nate

        --
        55 Commander Starlight
        http://members.cox.net/njnagel
        --
        55 Commander Starlight
        http://members.cox.net/njnagel

        Comment


        • #5
          In addition, you may want to "read" them after a few miles to make sure they are the correct heat range.




          Dick Steinkamp
          Bellingham, WA

          Comment


          • #6
            Thanks to all of you for the explanations and sage advice. I will install the RH-18Ys and check them 50 or so miles down the road for glazing.


            51 Commander State Sedan
            Butler PA

            51 Commander State Sedan
            Butler PA

            Comment

            Working...
            X