Modified Spark Plug?

[go-rebels]

I pulled the plug on my Whizzer and wondered why the threads were so long. Without modification, it would seem that there might be trouble turning an old plug out of a head after the threads get carboned-up.

Plus, the exposed threads would get really hot and possilby cause pre-ignition, especially with a little carbon.

It seems that there would be a benefit to put the stock plug on a lathe and turn down the un-needed threads such that there would only be threads required to mate with the threads in the head.

Opinion?

 

[Kep1a]

I opted to machine the plug recess in the head and then I just put in a short version of the long 10mm plug that Whizzer uses. I was able to get an exact fit too.

I had the same concerns as you and asked Dave why it was that way but he did not know. I got the idea to use a shorter plug from Quenton and figured that since I had the head off for a leak anyway I would just get that taken car of at the same time. I had to mill the head to make the head gasket surface flat too. It was way off. I'm not to keen on machining the replaceable spark plug as you described but that would prevent the ripping out of the threads in the head.