TIX

iTrader: (17)

That's what ive done in the past.
I'm still running the stock .4mm at the moment

I just find it odd that I'm having to add another shim over .4mm stock when the manual says you can remove to .3mm

Is anyone else having to add another shim for 30% fuel

Maximo

iTrader: (11)

what oil % do you run ? I have seen where the oils in certain fuels caused detonation...either the quality of oil or quantity...the higher the oil content the more likely there will be detonation.... The stock shimming and compression of the FX is perfectly fine for 30% nitro...

TIX

iTrader: (17)

I'm running VP Powermaster fuel. The mixture we import into Australia I'm told is 11% oil

TIX

iTrader: (17)

I ran them both in on 1 gal of Sidewinder 30% WC blend I had left over. Then switched to the VP that I usually run.

Maximo

iTrader: (11)

what glowplugs are you running ?

did the issues start once you started using VP ?

Lille-bror

yearh, you might need another 0.1 mm shim, when you run 30% nitro. More nitro = more shims. I still run the stock shims with 25% nitro, so give it a try.
And yes, 11% oil in a 30% mix sounds too much. You can compress the gas (methanol and nitro) but its not possible to compress the oil (if I'm not wrong :-) )

blade954

iTrader: (23)

Running 25% Byrons in mine and tuned to sound and smoke with performance comes in at 110deg C give or take, Been running the X3 plug and have not experienced any symptoms you speak of Tix....

Lille-bror

And how about a colder plug with all that nitro?

Colder plug = thicker coil = better lifespan and correct ignition timing

merdith6

iTrader: (3)

Yeah I don't think messing with the shims is needed. I do think this engine needs to be leaned out a bit more than the instructions say. This engine makes tons of power and you may just be running it too rich on bottom and top. it flies so it can be easy to leave it too rich. JMO. The #3 plug it comes with seems to last a long time. I got a few #4 plugs but I don't know that they are needed, but have not tried them yet. still on original plug.

TIX

iTrader: (17)

Im running the OS P3 plugs. I have some JQ 3 plugs as well. But they are all the same.

I would say the problem did start when I changed to the VP fuel. But I didnt start leaning it out until I got on the VP fuel. The sidewinder i was using was the same oil / nitro % mix

Maximo

iTrader: (11)

I would think a P3 is too hot and too fragile for a engine like this.......... I will be running a Werks #6 myself....... Also you can't always trust what these fuel companies put on the labels..Do not discount bad fuel ... I would swap to a different fuel and see if the issue goes away......

TIX

iTrader: (17)

Its not happening in my Nosram RR.21 on the same fuel with the same plugs.

Its also the manufacturer recommended plug.

I'm not trying to disagree. I just don't see how it's happening to FX but not the nosram.
I just finished the bottle so ill try a new one first then try another brand

Maximo

iTrader: (11)

They are two different brands of engines.......can't assume what is ideal for one is ideal for the other.......... as i say, by the math I wouldn't run a OS P3 in the FX.....To me the engine is too aggressive for such a fragile glowplug... and based off you crunching glowplugs I am going to say I am probably spot on....... You have no idea how many engines I have seen destroyed by OS P3 glowplugs..........yes they idle well, but they are as fragile as a snowflake and drop coils when subjected to any sort of pressure....Run a colder glowplug

TIX

iTrader: (17)

I have some O'Donnell 99 plugs. Would they be any good?
Ill see if sam has some Works plugs to try

houston

iTrader: (96)

they are a much cooler plug , you will usually have a trickier time tuning low speed but that plug lasts a long time