Re: 1924 Ruddertwin Spark Plugs

Home › Forum › Ask A Member › 1924 Ruddertwin Spark Plugs › Re: 1924 Ruddertwin Spark Plugs

January 30, 2017 at 10:16 pm #52157
Anonymous

    I have a rudder twin that the OEM Champion plug was a #7 (old numbering system) that converts to a modern D16. I tried a D16 and the plug stayed white, and was too hot as was the #7 that ran white. I switched to a D9 and now it runs a brown color, which is the correct color and is cooler. The D9 was a 5MJ or 5M.