6C plug is good only at lower temperature and high humidity (let's say humidity higher than 60% and temp lower than 20ºC)..........

if the head clearance is too small it's shortening glowplug life (not to mention the engine as well)........

try adding a 0.10mm shim and check the engine..........you also should try 7 and 8 plugs, specially for high nitro content.........

I'm going to replace those o ring in the carburator, what is the factory defaut setting for the low speed needle? Thanks for reply

Do OS turbo plugs work OK in a Nova based engine? I've run out of cold Nova plugs and will be running in 30 degree celsius weather this weekend!!

yup, I use white metal p6 and p7 plugs on my nova based engines with no issues, I find there heat ranging very similar to that of the nova plugs. you will want to use a P8 though if conditions are that hot!!
damn you with your lovely hot weather!

Thanks Hesky
It's hitting 30 degrees Celsius (86 degrees F) and we are still in spring! It's going to be a hot summer. Have to stock up on head shims and cold glow plugs!

How will a NSR12S5 compare with NS15S5?

NSR12S5 = .12 (2,11cc), 5 port with microcast piston

NS15S5 = .15 (2,5cc) 5 port with machined piston.

i know that

i just wanna know how's the real life performance will be like?

you can expect longer life with microcasted piston...........

besides you also notice the idle speed is more stable with the microcasted piston, specially when your engine reaches temp higher than 120ºC......

performance isn't any different.......

The extra displacement will probably give the NS15 extra low down punch, I think the NS15s are good for 1.8bhp compared to 1.6 with the NSR12.

I beg to differ.

The microcasted piston will produce more power for a short time, but it will by far NOT last as along as a machined piston from NR.

From what I've read that seems to be the case. It will be interesting to see how long my new mod motors go with there mc pistons.

you must consider that the microcasted pistons work much better even with loose fitting..........

a "poor compression" standard piston simply doesn't work while a very loose microcasted piston works very well............

BTW>>> both pistons are CNC machined the same way, the difference is in the casting proccess..........microcasting allows higher silicon content in the alloy which yields better heat expasion combined with ABC contruction sleeve.........

No, they are not. The machined piston is cnc ground out of a solid piece of aluminium and the microcasted piston is casted under very high pressure and temp.

If you look at the inside of an MC piston, you'll see the surface texture of the mold, while inside the CNC piston you can see the machining marks.

All the engines with MC pistons that I or friends of mine owned made great power for about 1 Gallon and then they lost all of their grunt.

It does allow for 20-25% higher silicon content.
I noticed both my jp and rb mod motors have mc pistons with areas of the piston machine finished like the inside of the piston skirt and the piston face, I guess as accurate the micro casting process is it will never cast to desired tolerances.
I feel the micro casting process is a way of reducing manufacturing costs and manufacturing time. more of an economic solution not a performance solution.