1930ish Spark Plug Caps Another Idea

Posted by JWL On 2017/7/19 13:41:52

Following up on my comment on the above referenced thread, I offer the following for those of us with engines having 10mm spark plugs. Seems to me an adaptor could be made to allow the fitting of 14mm spark plugs in these engines. Given, the end of the plug would be farther away from the combustion chamber, but maybe a projected core spark plug could help to over come some of this. Just a thought. Comments? Be kind. JWL

Edit:
Come to think about it, the idea will probably not work. The part of the adaptor that would screw into the head would not allow a larger 14mm plug to get anywhere near the combustion chamber. The only way would be to resize the 10mm hole to 14mm and then make an adaptor to take the plug. This way the 14mm plug threads would be fully supported. They are not when the 10mm hole of resized to 14mm as has been a practice. A longer reach spark plug could possibly make up the difference to have the end of the plug in a proper position in the chamber.

It is hot outside, typical Austin August summertime weather, and I am inside under the AC. Maybe too much time on my hands.