Originally Posted by
Glowgeek
Thanks for the link John, I had no idea 5/16-32 was a standard! That changes everything. Makes it possible to fab my own insert using my wood lathe.
Just got off the phone with Time Fastener Inc. They have never made a 1/4-32 Bigsert. They also have never made an insert from brass either. Both of the ones used in this engine are made from brass. I'm thinking you're correct, someone fashioned the inserts themselves.
I will give it a shot, worth a try.
Thats is interesting, they make a 1/4-32 time-sert in stainless, and in a copper plated alloy... specially for glow engine repairs mine you, and they never considered making one for their big-sert product line... I hope you made them think further about making one.
Brass is more durable than saito's base alloy, it also has very good thermal properties, helps to transfer heat away from these small spark plugs... not that these 1/4-32 plugs have much of a heat range to them... the ground electrode is so small, it will start to glow red hot with sustained rpm running too lean mixture, to the point it will run more like a glow plug rather than a spark plug, and actually continue to run on after you hit the ign kill switch.
Make a replacement in brass, red loc-tite it in place, and you'll have a robust repair, that should last a long time with proper care.