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Melted Glow Plug

Melted Glow Plug

Old 08-21-2010, 05:31 PM
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Hello everybody.


I am breaking in my new 0.18 engine but i have a problem with the glow plug. It has melted at the top edge of the coil so i have changed it with a new one but the same happened to the second glow plug.
Engine is running rich and temperature didn't get over 65C/150F degrees in the first five fuel tanks.
The glow plug is OS A3 and fuel contains 16 % nitromethane and 11% synthetic oil.

Is it normal or something goes wrong?
Also, after the break in period, what is the normal engine operating temperature?


Any help will be appreciated.
Thanks.
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Old 08-21-2010, 05:39 PM
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150F seems awful low for an engine break in. You need to get some heat in that engine to break it in.... You could just be WAY too rich and the plugs keep gumming up or predetonating? Get it up to 190+ for break in, but keep it under 220ish. No hard and fast rule....but most break in guides tell ya to get some heat in there so the sleeve has a chance to expand properly.
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Old 08-21-2010, 05:50 PM
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Originally Posted by MotoGod
150F seems awful low for an engine break in. You need to get some heat in that engine to break it in.... You could just be WAY too rich and the plugs keep gumming up or predetonating? Get it up to 190+ for break in, but keep it under 220ish. No hard and fast rule....but most break in guides tell ya to get some heat in there so the sleeve has a chance to expand properly.
+1
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Old 08-21-2010, 06:14 PM
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Between the fifth and tenth fuel tank i have pushed it a bit harder and temperature got up to 90C/194F. After the fifteenth tank engine temperature got over 110C/230F.
Is this temperature ok?
Also i am thinking to change fuel and use a fuel that contains 20% nitromethane and 18% synthetic oil as engine's manual says. Also i will go for a colder glow plug such as an OS A8 to eliminate predetonating. Am i right?

Thanks.



PS. It's the first time that i'm braking a new engine.
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Old 08-21-2010, 06:36 PM
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Originally Posted by rctech_new
Between the fifth and tenth fuel tank i have pushed it a bit harder and temperature got up to 90C/194F. After the fifteenth tank engine temperature got over 110C/230F.
Is this temperature ok?
Also i am thinking to change fuel and use a fuel that contains 20% nitromethane and 18% synthetic oil as engine's manual says. Also i will go for a colder glow plug such as an OS A8 to eliminate predetonating. Am i right?

Thanks.



PS. It's the first time that i'm braking a new engine.
Yes you can change fuel % but it can harm it to go down say for example i ran 30% then i decided to run 20% it can harm the engine but say u run 20% and want to run 30% it wont hurt at all and it wont require re break in.
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Old 08-21-2010, 07:24 PM
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Originally Posted by NitroXray80809
Yes you can change fuel % but it can harm it to go down say for example i ran 30% then i decided to run 20% it can harm the engine but say u run 20% and want to run 30% it wont hurt at all and it wont require re break in.
can you explain how it will harm it by going down in %?
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Old 08-21-2010, 07:43 PM
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i been told it wont, hurt a engine if you go up or down on nitro fuel if you where running 30 %, im pretty sure you just remove a shim and retune the engine .


but you might of, not heard this before that if you break your engine with lets say 20 % or 25% or 30 % that it will run a lot better.
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Old 08-21-2010, 08:05 PM
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Originally Posted by mudboger07
can you explain how it will harm it by going down in %?
I have done it on cars and it hurt because when i did it the tune would never hold.
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Old 08-21-2010, 10:19 PM
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Changing Nitro percentage shouldn't harm any engine as long as your shimming is correct. If you need to re-shim for 30% and you decide to step back to 20% (or vice versa) you may have issues.

Generally this isn't too big of an issue, but try and pick your fuel and stick to it if you can help it.....or in the very least don't be swapping back and forth every gallon ;-)
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Old 08-21-2010, 10:22 PM
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Originally Posted by rctech_new
Between the fifth and tenth fuel tank i have pushed it a bit harder and temperature got up to 90C/194F. After the fifteenth tank engine temperature got over 110C/230F.
Is this temperature ok?
Also i am thinking to change fuel and use a fuel that contains 20% nitromethane and 18% synthetic oil as engine's manual says. Also i will go for a colder glow plug such as an OS A8 to eliminate predetonating. Am i right?

Thanks.



PS. It's the first time that i'm braking a new engine.
Last engine I broke in I pre-heated it with my Competition Heat Engine Warmer to @ 160 degrees....fired it up...set my idle to medium high and leaned the LSN @ 3 hours to get the temps up[ past 180. Second tank I was past 190....3rd tank past 200....4th I was at @ 215 and left it there for @ 2 tanks...then I dropped it on the ground and drove it slow with throttle blips for another tank or so....then I put a base tune on it and hit the track. I waited until the pinch was gone to fully race tune it.
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Old 08-31-2010, 07:20 AM
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Hi guys.

I am very disappointed with my new engine, something goes wrong.
I have changed fuel and i am using now a fuel that contains 20% nitromethane and 18% synthetic oil (according to the engine's manual nitro must be between 10% and 30% and oil between 5 and 18%).
Now i am taking too high temperatures(over 135C/275F).
I decided to change the glow plug with a colder one in order to drop the engine's temperature, but it continues to be too high.
Engine is running too rich (a lot of smoke and engine is bogging).
Something last, engine goes off very often and after that it doesn't start easily.

Is it normal in such a rich mix to get too high temperatures?
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Old 08-31-2010, 09:09 AM
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18% oil is way too high of an oil content in my opinion. Engine tuning problems can be many things, and running too rich certainly is one of them, these engines need the proper air/fuel ratio to run right, so being too rich or too lean are both problematic, and incorrect.

Also, changing nitro percentage is NOT going to hurt your engine if it's shimmed correctly ( many race engines come shimmed for 30% already, meaning you may need to remove a shim when you drop nitro % )

If your engine won't start after putting in a new plug, you're likely too rich on the low speed needle, or have too small of an idle gap ( which isn't likely if you're running too rich ) it could also be flooded. It's hard to tell you what to do without being there and listening to it though. Tuning by temps is also misleading, so be careful when you do that. Nitro tuning is a little frustrating at first, but when you learn to listen to how an engine should sound, you won't need that temp gun for racing.
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Old 08-31-2010, 09:13 AM
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18 % holy crap thats a lot lol, yea tune my smoke and performance but check it when you come into the pit or after you race.

and run at hotter plug or a meduim plug it will start and idle better.
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Old 08-31-2010, 09:29 AM
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18% oil is way too much...that would make it want to run very hot and tuning very difficult...
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Old 08-31-2010, 09:39 AM
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Are you using a car fuel or an aviation fuel?

An 18% mix is most likely made for helis or planes...way too much oil for cars. If you got it to run you are most likely way too lean and burning up your plugs after the engine heats up.

Get a quality 20-30% fuel that's made for cars and reset your needles back to stock before attempting to start it. Warm up the engine block and head with a blow dryer for a few minutes before starting and avoid direct heat to the carb.
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