AutoLite 216's in Offy heads

[GOSFAST]

Originally Posted by qmdv

Then let me try again. I have offy 375 heads. With exhaust valve fully open there is .615 between the top of the exhaust valve and the spark plug mating face on top of the heads. If I used 3/4 reach plugs with a .125 spacer, the plug would interfere with the valve and that would be bad news. I was hoping that somebody had some help they good give. This task would be a lot easier if I had heads with deeper combustion chambers.

Just to keep things clear here, you don't necessarily need the .125" spacers, you can make them any length to get the job done!

The .125" spacers happen to fit the Offy heads we generally work on here!

Thanks, Gary in N.Y.

P.S. Here's an example, if you start with the .750" plug and make the spacers .250" you now have a .500" reach plug. You also need to consider the plug washer thickness, .025" (nominally).