After a good few years nitro bashing and now racing this is the 1st time I've stumbled across this seemingly un explainable problem. for a little rc fun I purchased a revo and an rb tm323 engine, while running the engine in it manged to kill 2 plugs on the 1st few tanks. I though this was just part and parcel of the pains of running an engine in (never had this happen b4 though) I continued to run it in and another 2 more plugs bite the dust and I'm on my 8th tank nearly completed the breakin in proses. I check the engine out for play and pinch and all seems fine, come to start it and you guessed it another dead plug engine was super rich of course never running more than 100c, indicated by my temp gun and the h2o test.
plug wire is alway in good shape, wet and silver, but strangely dead
I'm not bothered about a few plugs dying but so far its going though more than 1 plug every 2 tanks!! so I'm not to keen on this average
I've tried 3 different glow starters, used 2 fuels 16% tornado lube+ now 25% odonnel oh and 2 different brands of plugs. engine runs like a scalded cat, even below optimum tune but still with the glow plug issue of course.
Anyone out there shed some light on this problem short of blaming mice that live on a diet of glow plugs I'm at a loss

just a side note, the plug is always dead when I come to start the motor, never flames out and dies.

Try to add some head clearance and see if this solve your plugs problem.

Yes daniz24 may be on the right track. Also check the bad plugs for coil distortion. Depending on the nitro % you may have too high a compression and it may be killing the plugs.

Worst case add a .1mm shimm and see if it corrects the problem.

John

thanks for the reply guys, im running the stock 0.3mm head clearance, actually measured them to make sure because just like you I thought maybe a compression related issue. as I said every plug run looks new, element is always in good shape and silver. if i poke the plug wire while its in the glow starter it starts workin again like the wire is broke from the base of the plug hole. ive tried 10%, 16% and 25% nitro content fuels but issue continues regardless.

What plug is that.
As I know last year there was bad batch of Novarossi plugs ( Iw as told that-can't confirm if this is correct), but after then it was OK.
One more thing which can do this damage-badly unbalanced motor. Is your motor modded or stock?
Any way check balancing.
Edward

hi ed, I'm using the recommended rb plugs code 1055-trx which ive been told to stick with by the guys on the rb forum, i dont like them they seem a little fragile. used a few odonnell plugs but they die just as fast. my engines non modified and all components seem fine when I stripped it, although after break-in there is evidence of a very slight amount of play between the conrod bush and crank pin, I've ordered a new rod but rody said the tm323 motor has a slight amount of play there anyway so if thats from the horses mouth so to speak I shouldnt worry to much. I will change it non the less.

cheers

I don't think that small play will create your problem. Per your description, first I will do is to check balancing. May be it is not on motor, may be it is on you clutch, but defenetly something is shaking fillaments off.
Edward

rod/crank pin may b worn

ooh, come to think of it I have EXCESSIVE unbalanced bowtie tires I mean really unbalanced! I think theres an art to assembling these rather large mt wheels which im yet to learn (used to glued and trued 10th foams). sorting them out was low on the lists of priorities, getting the engine run in was at the top. while I was doing the wot process with the truck on the bench rpm was low but the vibrations from the wheels were hi, i could see the head of the engine trashing about.
I guess its not direct vibrations or as frequent such as an unbalanced engine but its vibrations non the less, maybe resonant to the glow plug wire who knows

My buddy is having the same issue with his factory OS CVR. His OS 8 glowplugs are distorting and melting the coil too. Same deal... it will keep running, but after it stops, you try to start it and no voltage can get through the plug.

This makes sense because the engine heat would keep the remaining coil glowing even if part of it is melted, and this would be enough to keep the engine going, but will not allow the coil to let voltage pass through it to make it glow for starting.

Anyway, my suggestion to him was to switch to a colder plug. This seems to have completely fixed the issue for him. Even though an OS 8 was recommended, he went to a colder McCoy plug, and this fixed it. It's quite possible that manufacturing tolerances were slightly different on his engine, and yours, and this makes for higher compression, producing more heat, and therefore more problems with glowplugs.

Of course, you're talking about turbo plugs which are different, but the theory might work for you too.

yeah that would suggest excessive overheating though. a few days ago I started leaning out the motor and tuning it for performance running my 25% race fuel always keepin an eye on temps as it is now fully broke in. I'm letting it run at between 100-110c as apposed to 80c for break in running 16%. no dead plugs after a few tanks so heat isnt the culprit, that I'm sure of.
I'm pretty sure ed's onto somethin, as it happens regardless of temps. I've never seen a plug with melted or even grey wire as I alway run just below optimum, I simply dont let my motors run that hot.

I have an uprated 3 shoe clutch which I was going to save until I was really happy with the engines tune and the trucks setup, but I guess it will have to go in now, along with a new flywheel and different clutch bell. I really want to look into the potential of any vibration issues! I'm gonna also try some different wheels.
I stripped the motor again checked bearings for play inspected all parts especial the crank for any strange visual abnormalities, but it looks and feels like any rb engine, perfect.

Can anyone recommend a substitute for the Novarossi C6S plug? I would like to run an OS or McCoy plug (they are more available in my area). I will be using the plug in a Novarossi N528XSP engine.

Thanks,