Spark plug electrode damaged top of piston

[Manny]

Hello everyone, just started in 1/5 scale RC and have really enjoyed the 2 hours I spent driving my new KM X2. I was wondering if anyone has experienced anything like this, the tip of the electrode broke off my spark plug and damaged the top of the piston causing the engine not to start again. The brand of Spark Plug is INT h-cmr6 which is the original plug that came with the car. The question is what would anyone recommend I replace it with, should I go with the KM replacement or is there a Zenoah top end that would fit it, thanks for any feedback. I have included some pics.

 

[evssv]

ngk every time......them plugs r cheap for a reason.?..which u have now discovered.......i`d stick a new piston/ring on it and a ngk and it should b fine...
is the barrel marked at all?if not it should b ok...

 

[crucialRC]

I saw it on YouTube on one of Botajell's videos. I believe it was on one of his Rovan engines. He ended up using another plug washer to raise the plug a few more mm. He said after the washer install all was good.

 

[Z.hb71]

I saw it on YouTube on one of Botajell's videos. I believe it was on one of his Rovan engines. He ended up using another plug washer to raise the plug a few more mm. He said after the washer install all was good.

No, what he was talking about was the piston was banging the plug because the squish was too tight caused by a too thin head gasket. This guy's problem is that the electrode simply fell out, as you see the tip of the plug (that metal L shaped thingy, don't know what it's called) isn't squished down in the direction of the part were the plug wire attaches, just the electrode fell out. Wasn't hit, just a cheap plug. Hope I managed to explain decently

 

[crucialRC]

No, what he was talking about was the piston was banging the plug because the squish was too tight caused by a too thin head gasket. This guy's problem is that the electrode simply fell out, as you see the tip of the plug (that metal L shaped thingy, don't know what it's called) isn't squished down in the direction of the part were the plug wire attaches, just the electrode fell out. Wasn't hit, just a cheap plug. Hope I managed to explain decently

OOhhh. Gotcha Z. I misread the post. Sorry, yeah I'm definitely with E on this one then. Get some good NGK's.

 

[JRRC005]

BY THE LOOK OF THE PISTON IT WAS DOING IT FOR A WHILE.

 

[1Coopgt]

Time for a new Piston, Ring and head. I'll second NGK for small engines .

 

[Top Dead Center]

Look at the bright side. Now you have a 36cc engine. Looking at your pics, it doesn't look like a total loss. As far as I can tell the cylinder wall is not scored, so you should be good to go. I would remove the piston ring, the piston from the connecting rod and lightly file any high spots on the circumference at the top edge of the piston. Then file off all the high spots on the piston crown. Put it back together and have fun.

I would recommend ordering a piston/cylinder kit just to have on stand by.

 

[1Coopgt]

Look at the bright side. Now you have a 36cc engine. Looking at your pics, it doesn't look like a total loss. As far as I can tell the cylinder wall is not scored, so you should be good to go. I would remove the piston ring, the piston from the connecting rod and lightly file any high spots on the circumference at the top edge of the piston. Then file off all the high spots on the piston crown. Put it back together and have fun.

I would recommend ordering a piston/cylinder kit just to have on stand by.

The cylinder walls may look ok but the combustion chamber dome is shot . It looks as bad as the top of the piston. If it were me I'd replace the whole top end. Depending on how long he's had the buggy, if only a couple months I'd be bitching up a storm to King Motors. I'd want the engine replaced or them to send a new topend. I've never seen an electrode fall out of a spark plug before in my 40 plus years of working on all types of engines.

 

[TODD]

I've never seen an electrode fall out of a spark plug before in my 40 plus years of working on all types of engines.

It is not really that common but it does happen sometimes. Porcelain break, electrodes fall out, ground straps break off, glue joint between porcelain comes loose. These things do happen. Seen all of
them working on engines.

 

[bigdipperfred]

Like Todd said it happens. I had a 5.4 Ford the day this happened to. The plug was loose probably the vibration caused that failure.

 

[Top Dead Center]

The cylinder walls may look ok but the combustion chamber dome is shot . It looks as bad as the top of the piston.

I disagree but, I also have a toolbox drawer full of die grinders, extended arbors, steel burrs, flap wheels and abrasive discs. I think it can be saved.

It appears that all of us got distracted by the pics of the damage and glossed over the fact that he only has 2 hours of run time on his X2. He shouldn't be spending any money on repairs. He should be raising hell with King Motors as soon as possible.

@Manny first of all, welcome to LSF and the 1/5 scale hobby. It sucks that this is your introduction to the hobby. Assuming you bought your X2 new from King Motors RC, I would email them the pics you posted here and call them at 9:00AM EST. Let us know how they handle your issue. You might even want mention that you have a thread started here.

Best of luck to you, Manny

email: [email protected]
phone: 845-268-0088
Office hours are Monday through Friday 9am to 4pm.

 

[Manny]

Thanks to everyone for the comments, I really don’t mind the problem I know it’s part of the hobby, I did send KM an email requesting the replacement of the engine, I’ll see what they say. I do have a replacement piston ring and will try to salvage the head and the piston see if it works, and if it doesn’t I hope KM replies back with good news.

 

[JRRC005]

what brand spark plug is it, when I got my buggy from king it was a n g k sparkplug.

 

[1Coopgt]

I disagree but, I also have a toolbox drawer full of die grinders, extended arbors, steel burrs, flap wheels and abrasive discs. I think it can be saved.

It appears that all of us got distracted by the pics of the damage and glossed over the fact that he only has 2 hours of run time on his X2. He shouldn't be spending any money on repairs. He should be raising hell with King Motors as soon as possible.

@Manny first of all, welcome to LSF and the 1/5 scale hobby. It sucks that this is your introduction to the hobby. Assuming you bought your X2 new from King Motors RC, I would email them the pics you posted here and call them at 9:00AM EST. Let us know how they handle your issue. You might even want mention that you have a thread started here.

Best of luck to you, Manny

email: [email protected]
phone: 845-268-0088
Office hours are Monday through Friday 9am to 4pm.

TD you could try what your saying but if you start grinding on the piston and the combustion chamber it will lower that compression ratio by quite a bit I would think .

 

[Manny]

what brand spark plug is it, when I got my buggy from king it was a n g k sparkplug.

INT - the brand they sell on KM website

 

[Z.hb71]

INT - the brand they sell on KM website

Aka China clone junk as you've discovered. My rovan buggy came with a ngk, so it's a hit or miss. I wouldn't touch another "int" plug with a 10 foot pole let alone put one in my motor.

 

[Manny]

KM replied they will send new head, piston and spark plug.

 

[Z.hb71]

KM replied they will send new head, piston and spark plug.

That's awesome!!!! Just don't use their plug cuz u wouldn't want to risk it again would u?

 

[Manny]

Aka China clone junk as you've discovered. My rovan buggy came with a ngk, so it's a hit or miss. I wouldn't touch another "int" plug with a 10 foot pole let alone put one in my motor.

I bought an NGK and an E3 will give both a try once the parts get here.