jase5.2

Hello newb here! I recently bought my first RC Nitro car - a Tamiya TNX 5.2R. I broke the engine in pretty much as desribed in the manual - never went over 50% revs for the first 5 tanks.

After about 1 and a 1/4 litres of fuel had been through the car the stock Glow Plug went - not totally because it still glows but every time I took the Glow Starter off the plug the engine would stall.

I put an OS8 Glow Plug in which worked fine. I ran a tank of fuel through it (max temp 227deg), refilled, and went to start the engine... nothing! The plug had failed (wire broken and spring pushed to one side) after only one tank.

Today I put an OS A5 plug in and richened the mix up. Exactly the same thing happened - plug failure after one tank had been run through (max temp 200deg).

I'm puzzled that the plug only seems to fail the engine has run out of fuel? Can a plug retain heat with a broken coil?

I've cleaned the cylinder head out after both failures and removed what little dirt had managed to get in there (on this last occasion mainly bits of glow plug coil).

Any suggestion as to what I'm doing wrong here? This is driving me nuts! []

Dil

dude you have plenty of room to go leaner theese engines dont like to work at low temps, get it around 250 260 F thats a normal temp,

the only reason for the engine to fail once you took the plug heater off is that its running way too rich, lean it up and it should fire up, start it up and give it some gas to get it to temp, running these motors too rich will only reduce the engine life,

and are you sure your plugs are burnt off, just cos the engine stalled doesent mean the plug had failed,

good luck,

jase5.2

Cheers for the reply. In the case of the last two plugs they're definitely gone. Coil broken in the second and half the coil missing in the third... The first plug will still start the engine but it stalls as soon as you take the heater off.

gbravo_25

i had the same problem since last week but now seems that its ok i was using 25% nitro now i turn to 15% i think if u r not going to race 15% is good and i m using n5 but not OS bec with the OS n5 i still had the same problem now i m using robbe n5 1.2v - 1.5v and i have changed the fuel pipe bec it was gam and i had low fuel coming up the the engine ws coming very hot but today i went very much better i really hope i m over this problem bec since now i have changed about 7 plugs with 3lts of fuel

hope this will help u

jase5.2

Well, I think I've managed to get to the bottom of this.

I believe that what happened is that some sand got into the cylinder head through the glow plug opening. Although I did clean the cylinder head out after the 2nd plug went I must've missed some or it had gotten into the carb or something?

I pulled the engine out - cleaned it thoroughly with loads of WD40 and all seems to be well now. Fingers crossed.

MadDogRC

no offenc but learn to read. in the tnx manual it states to use between 20% - 30% nitro fuel. 15% nitro fuel is too low and is more like run in fuel. i run 25% and i just bash but its got so much more power in speed!

gbravo_25

don t worry i know how but i had really problems with the 25% thats why i changed it. so in few words u r saying that its not the fuel my problem was right??