RE: Engine Knocking
Jim and Jan,
I don't agree!
The idle-bar is intended for older engines.
These had a baffle-piston and/or a 'less than satisfactory' carburettor; both of which can lead to rather large fuel droplets being thrown directly at and possibly dousing the glow-element...
This in turn could lead to the engine conking-out, especially during idle...
But; many engines that have a very good carburettor that finely atomizes the fuel and modern Schnürle porting that does not 'throw' fuel directly at the glow-plug, run just as well with an idle-bar plug of the correct heat-range, as they do with a normal glow-plug.
One such engine is the MVVS .49 GFS/R, which I am sure you, Jan, are well acquainted with; and which has one of the best carburettors around.
When an idle-bar plug is installed, it loses none of its reliability and there is no RPM loss either; I have been reported.
The plug was a Fox R/C Long and the comparison was both to an OS #8 and to its original Novarossi C-6S, although it was the OS got a slightly lower top-end (50-80 RPM less).
The idle-bar does not 'keep the fuel away from the fire', as some people fear it could.
If either of you can show that in a certain engine, the idle-bar will actually cause running to become substandard, compared to a normal plug of the same heat-range; go right ahead and post these results!