AW GEE Jester! Here is one we kind of disagree with. In my not-so-humble opinion, The O.S. #8 is the most highly over-rated glow plug that has ever been levied on the RC pilots. OH SURE it is fine and does well but the over-rating comes from the fact that Great "Pains" and its sub-chapter "Tower" needs such a reputation just to maintain that highly over-rated price.

Now for anyone wanting very good performance at a much lesser cost, simply try the McCoy 59, which is an excellent choice for most flying. If running a fuel or system using the OLDer single bypass engines, then the MC-50-Idle Bar will do the job. The idle bar will last a bit longer when using nitro of 25% or more. Back in the olden days when I did pylon racing, '70s and 50-70% nitro, these cold plugs could get 2 flights. Other plugs were lucky to get one into the last lap. In reality I use the MC-50 most of the time in all my flying.

Hey slider_buck, best wishes to you. Almost any current glow plug will do well in sport engines. Some quit on the first flight and some never quit. Jester is usually 101% right on all his help, so I just have to spoof him a tad bit.