RE: Blown Glow Plug
Al's interesting to talk to. Some years back, at a Combat meet, the subject turned to glow plugs. He's sectioned lots and lots of them over the years, and wanted to see what some cheap Chinese ones I'd just bought at Indy RC were like inside.
He started talking about plug elements - what metals go in them, and why, and plug construction, and why Fireball plugs blow seals. It turns out there are only a few companies making plugs in the U.S. - Cox, Fox, Ohlsson and Swanson (Fireball). There may be one or two more (not sure if Nelson makes his own, doesn't look like Ohlsson construction, but the seal method is the same, and now Al's making plugs too). Most of the plugs you see around - McCoy, K&B, Thunderbolt, etc. are OEMed by Ohlsson (yes, that Ohlsson which made the O&R engines, they're still around, but don't make engines any more). The K&Bs and McCoys look identical when sectioned.