Re: Why the 10mm spark plugs?

Posted by Owen_Dyneto On 2017/1/11 11:13:53

I just checked the plug location on 2 cylinder heads from 320 engines, from a 1934 Eight with 14mm plugs, and 1936 Eight with 10mm. Plug location is identical and of course, over the valves. Going back a bit, there is a nice engine cross-sectional view in the 326/333 owner's manual that shows the plug location in the same place; as I recall those plugs were 7/8 NPT thread, and later 18mm.