Originally Posted by
John_M_
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.
Thanks John.
I asked Time Fasteners why they didn't make a 1/4-32 Bigsert. They said that the standard Timeserts work so well that there wasn't a high enough demand to justify the tooling cost. They also claim that a properly installed standard insert should outlast the life expectancy of an engine. Makes sense, the torque requirement is very low on glow plugs and they are infrequently removed.
I will be forced to use hi temp/hi strength loctite to capture a custom fabricated brass insert because there will be no locking feature, other than tightening the shouldered insert into place. Will loctite survive the temps experienced at the spark plug? Hmmmm