Damaging Glow Plugs

[nareik72]

Hi all,

 

 I have a new LRP ZR28 Spec 4. I ran the first few tanks gently with the provided glow plug, eventually, it failed. I replaced the plug with a brand new one and ran another few tanks through it yesterday no issue. 

 

I took the car out today and it wouldn't start, checked the plug and there was no glow, the filament inside of the plug looked very damaged.

 

I replaced the plug with another new one, checked it and it was fine. Placed it in the car, pulled the starter a few times and again it wouldn't start. I checked the plug and it looked exactly the same as the one I'd just replaced, very damaged filament and no glow. Is there a reason why this may be happening? I didn't see anything online suggesting I'd need a specific type of plug.

 

I used standard glow plugs with a washer. The car ran fine on the same type of plug yesterday, I only pulled the starter a few times today and broke 2 plugs. I have attached photos of both plugs. 

 

Thanks in advance for your help!

[Nitroholic]

There is no such thing as a 'standard' glowplug.....

They have various different heat grades, which are rated from 'hot' to 'cold' .... though that has nothing really to do with how hot your engine gets.

 

Your glow plug has melted its wire, which is not good. It potentially means your motor got way to hot. If your motor is still on 'factory' settings, for break-in, then it should be runnign cool and very rich. Have you checked the needle settings are right for break in? Also...check the fuel pipes are secure, your tank is sealing, and hte pip e form teh exhaust to the fuel tank is tight fitting and not kinked. If you have the carb needles set right, then there is another issue.

 

Are you able to check the temps the motor is running at? This also might help pin down the issue.

 

Also....what fuel are you using? The LRP motor is quite a powerful unit, and it;s possible you are getting detonation, rather than proper burn. This can cause temperature spikes that melt the glowplug. The .32 motor in my Savage would not run right on 20% nitro, but ran cool and swet on 25%.

 

Lastly...running in with hugely rich mix can also cause glowplugs to fail.....

 

so...

1) Get an  IR temp gun..they are cheap on the internet...as long as you don;t buy an 'RC Branded' item....

2) Check you have the right glowplugs for your engine

3) Check you have a fuel the engine is designed for

4) Check your carb is properly setup for break in, and be prepared to tune it a little

5) Physically check the fuel supply is good, and you are not running it lean for some reason other than carb settings.

 

Then see how you go!

 

EDIT: Also check what your glowplug igniter is doing. If you have a multi meter....it should only push out 1.5V ..... more than that, and it will fry the plug!

Edited June 15, 2021 by Nitroholic

[nareik72]

Thanks for the reply,

 

I've had to lean out the LSN somewhat to actually get the engine to idle.  It's still spitting a decent amount of out of the exhaust and I'm having to put an old rag over the engine to keep some heat in the engine. Barely going over 150 degrees F according to the temp gun. Only breaking it in so just idling doing short slow figure 8's

 

I'm running on modeltechnics 25% and while it may not be the best, but I've never had any issues. 

 

I'm running on #3 plugs which I believe are "medium/hot" they're just spare ones I had, I've always used them with no issue

 

And I'm only using a cheap 1.2v igniter that I've always used. I'm just confused as the 2nd plug died and the engine hadn't even fired. Literally pulled the pullstart a few times and the brand new plug was knackered. I've just had a quick check of the fuel tank/tubing and everything seems perfect, its a brand new buggy.

 

Just confused as I've never had this happen before.

 

Thanks again for the reply! 🙂

 

 

 

 

[Nitroholic]

Shouldn;t be touching the LSN for idle.... that affects other things too, which you don;t want to be doing if you can help it.

 

But...melting a glowplug wire before you started the engine sounds like an issue with the igniter. Either that or the plug was just faulty. That can happen

[turok007]

not owned a lot of nitro  but i found out the biggest cause of my glow plug issues were over voltage.