Nitroholic Posted September 22, 2011 Share Posted September 22, 2011 Not sure what would work best on this motor. Will be running on 25% nitro and the manual recommends a medium/cold plug. Gut instinct says McCoys MC9 as it's tried and tested....but there are other options which I have never tried. Are they worth bothering with? Modeltechnics F4 is cheap ... but I have never used one. LRP Iridium R5 looks better...but as I need two, it's a bit more to spend. JP No4 is another option that seems cheap Quote Link to comment Share on other sites More sharing options...
R46 Posted September 22, 2011 Share Posted September 22, 2011 mccoys don't work for me firepower sub standard avoid Lrp good I use nova rossi mostly c5 & c6 and picco plugs Quote Link to comment Share on other sites More sharing options...
jony nitro Posted September 22, 2011 Share Posted September 22, 2011 OS 8 are good, Mcoy 9 yep and Odonnels plugs Quote Link to comment Share on other sites More sharing options...
kingscott Posted September 23, 2011 Share Posted September 23, 2011 OS 8's (medium) Always do me well with the .28, most of the lads at the club use them. You can get them for around a 5er a go and are always available at most places. Quote Link to comment Share on other sites More sharing options...
R46 Posted September 23, 2011 Share Posted September 23, 2011 john if able to stop at 308 grab a few picco plugs med & med/cold £4 each Quote Link to comment Share on other sites More sharing options...
ajlovering Posted September 24, 2011 Share Posted September 24, 2011 The plug temp helps with the engine timing. As the piston rises and pressures up the air fuel mixture the temperature rises. At a given temp the methanol reacts with the Rhodium/Platinum electrode and you get ignition. If ignition is before the piston reaches the top (TDC) then the ignition is said to be advanced. This gives good low torque at the expense of high revs. If ignition is after TDC then its said to be retarded = high revs with loss of torque. Lots of things effect this timing. adding Nitro methane lower the ignition temp so advances ignition. Removing head shims increases head temp at TDC so advances ignition and changing the plug to a hotter plug also advances ignition For the most power you want the highest pressure in the head and ignition just before TDC. To do this remove the head shims and use the lowest temp plug you can find. This is just one of the many factors in tuning a 2 stroke glow engine. Dont get me started on exhausts! Cheers Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted September 24, 2011 Author Share Posted September 24, 2011 Hence my wanting a cool plug rather than an OS8 (medium). As mentioned above, the glowplug is not just there to make the engine go...it needs to bw the RIGHT plug to make an engine go well with the chosen fuel. I am running 25% nitro in large engines, so cool or medium/cold plugs are what I choose. It's also easy to get in a rut with plugs and always buy the same brand and ignore the options But....at £5+ a time, I want to be sure I am not buying something that won;t work. Think I will give the Piccos a go and see how I get on Quote Link to comment Share on other sites More sharing options...
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