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Old 01-04-2008, 01:25 AM   #1
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Default Eating through glow plugs today? A costly day.. Why?

Hey Guys,

I spent the day at the track today with a friend. we were running 3 buggies and went through 6 glow pulgs. What is the casue for a glow plug to burn out so quick. At $5 a piece that sucks.

I was running odonnell's purple which is a meduim temp plug in a hyper .21 motor and a picco .27. Running Odonnell 30% race.


The motor temps were in the 200 to 240 range. Smooth power in the power range.

What would be casuing this? lean? temps were good?


What should the head clearance be when running 30% fuel? I want to make sure the heads are shimmed right before something goes worng..


Sorry for all the questions... Thank again for the help.
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Old 01-04-2008, 01:27 AM   #2
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What plug temp (cold, med, hot) would you run with the big block motors.
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Old 01-04-2008, 01:28 AM   #3
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How are you stopping the engine Mpowers?
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Old 01-04-2008, 01:32 AM   #4
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They have good compression? Try installing a 0.10mm shim and see if it still eats plugs. Are the glowplug wires pulling out, pushing in, grey and distorted or just broken. Also what color is the exposed edge in the combustion chamber? Should be golden brown or honey color on a silver glowplug is the mixture is tune correctly.
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Old 01-04-2008, 01:53 AM   #5
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What plug temp (cold, med, hot) would you run with the big block motors.
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Old 01-04-2008, 01:57 AM   #6
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Quote:
Originally Posted by SH View Post
How are you stopping the engine Mpowers?

I stop the motors by plugging the end of the stinger. Is this the most common method?



For checking the head clearence with sodier. what show it mic out to be? How many thou?



As for wire colour is looks to be a bit grey..
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Old 01-04-2008, 01:59 AM   #7
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Quote:
Originally Posted by Mpowerz View Post
What plug temp (cold, med, hot) would you run with the big block motors.
I think generally you want a colder plug with a bigger engine, and also a colder plug with a higher nitro content in the fuel...however I am using a hot plug with my .28 and 30% fuel and have been using the same plug from the break-in period and the past gallon of fuel after the break in and it runs great, however it's anywhere from 30-50 degrees outside where I'm located so that plays a role as well.
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Old 01-04-2008, 02:11 AM   #8
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Originally Posted by revo_race View Post
I think generally you want a colder plug with a bigger engine, and also a colder plug with a higher nitro content in the fuel...however I am using a hot plug with my .28 and 30% fuel and have been using the same plug from the break-in period and the past gallon of fuel after the break in and it runs great, however it's anywhere from 30-50 degrees outside where I'm located so that plays a role as well.

I was running at a indoor track around 60 to 70 degrees inside. Even with running these motors at 220 to 240 that is not enough to tune them i am guessing.

There was a good amount of smoke coming out at WOT.
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Old 01-04-2008, 02:25 AM   #9
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Are they blowing out when running or they won't restart after turning them off? I personally have not blown a glowplug by blocking the pipe stinger to turn it off. I had some issues with tuning very tight new engines, so I added a .10mm shim and they seem fine now.
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Old 01-04-2008, 02:39 AM   #10
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Are they blowing out when running or they won't restart after turning them off? I personally have not blown a glowplug by blocking the pipe stinger to turn it off. I had some issues with tuning very tight new engines, so I added a .10mm shim and they seem fine now.

When you say adding a shim do you mean adding another shim? The motors already have sims..

What should the squish be bettween the pistion and the head?
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Old 01-04-2008, 02:46 AM   #11
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Squish is not the same for every engine. Some can get away with tighter clearance than others. As for shims, you may add another one and see if it cures the issue. I don't know what you engine comes shimmed for, but Novarossi's come shimmed for 25% nitro and you usually add .10mm for 30%.
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Old 01-04-2008, 02:54 AM   #12
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Quote:
Originally Posted by Mpowerz View Post
I stop the motors by plugging the end of the stinger. Is this the most common method?



For checking the head clearence with sodier. what show it mic out to be? How many thou?



As for wire colour is looks to be a bit grey..
Ok i would stop pluging the stinger or covering it to stop the engine, this will pop glow plugs & or reduce the plugs life. Either stop the engine at the flywheel (engine must be at idle) or pinch the fule line near the carbi.

stopping it at the flywheel causes like a back fire or similar within the engine.

your engine uses standard style glow plugs correct?

i would run a medium temp plug.

If you can get your hands on some LRP plugs i would highly recommend it, these are the best plugs i have used in a long time. If not try a OS #8 they are a medium temp plug.
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Old 01-04-2008, 03:45 AM   #13
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The most common cause of this would be that your connecting rod has to much slop in it. Adding a shim can be a good track fix but you should replace it as soon as you can.
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Old 01-04-2008, 04:22 AM   #14
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The most common cause of glow plugs failing is running the engine lean. I would start by richening up the engine and putting the temp gauge back in the pit box. Tune until the engine feels right and stops blowing plugs.
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Old 01-04-2008, 09:10 AM   #15
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Quote:
Originally Posted by kmorast View Post
The most common cause of glow plugs failing is running the engine lean. I would start by richening up the engine and putting the temp gauge back in the pit box. Tune until the engine feels right and stops blowing plugs.
+1

You can have good temps but still have a lean spot in the tune.
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