aspeed

Even short reach plugs are getting harder to find now. I would at least try for turbo plugs. They are harder to machine but have a smaller diameter than the Nelson plugs and there are a larger variety of heat ranges and brands available.Henry did kind of retire too, although other guys re making them like Merlin. An OS plug is half way between a short and long and would work but power would be down. I did a few .049 plugs for short reach plugs and they need a counterbore just the right size so the Cox plug wrench still works and you can still get the 5/16" wrench in for the regular plug. I then sanded off a few thou. off the bottom of the plug to get some more compression back. It has to be done very evenly with 400 sandpaper on a plate of glass or machined on alathe and if gone too far it will touch the top of the liner and that should be removed too. I am guessing the same thing for the .09. I just got a tap for the Turbo size (8mm by .75 pitch) after making a bunch for short reach after doing some .049 and Rossi .15 heads. I am holding off on the Tee Dee .09 till it blows. The little ones run better without the regular plugs.AP still makes an .09 real cheap, but the size isgetting less popular with the leckies on the scene now.