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Old 04-10-2010, 06:38 PM   #1
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hey there all. so with some assistance from you all here and demonstration from a buddy, i learned how to install and shim my clutch bell. i ran into another problem. i popped the coil on the glow plug today.. twice. one guy said that is cause i was running it too lean. i do not have a good temp gauge so i cannot tell you how hot is was but i was getting a good amount of smoke from the pipe.

it is a force .28 motor with an ofna 063 pipe. the plug needed is a long one with no idle bar. i popped the wire on an o.s. plug and a traxxas plug. any ideas?

oh, and when would i use a hot, medium or cold plug?

oh and i am using 20% odonnells fuel

ben
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Old 04-10-2010, 06:57 PM   #2
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hey there all. so with some assistance from you all here and demonstration from a buddy, i learned how to install and shim my clutch bell. i ran into another problem. i popped the coil on the glow plug today.. twice. one guy said that is cause i was running it too lean. i do not have a good temp gauge so i cannot tell you how hot is was but i was getting a good amount of smoke from the pipe.

it is a force .28 motor with an ofna 063 pipe. the plug needed is a long one with no idle bar. i popped the wire on an o.s. plug and a traxxas plug. any ideas?

oh, and when would i use a hot, medium or cold plug?

oh and i am using 20% odonnells fuel

ben
If you're blowing coils on your glow plugs, you are indeed running too lean. You should always tune by engine performance first, and temp second, which it sounds like you're trying to do. In this case, it seems like you needed to richen up the mix a bit. Without more details, it would be hard to tell if it's the low end or top end.

In a pinch, the "spit test" works well. Take a small drop of spit, and put it on your head. If it boils off immediately, your're too hot, if it just sits there and never really evaporates, then you're too cool. You want to to evaporate off in 2-3 seconds. Like I said, it's not an exact method, but it will give a general idea of how hot your motor is...
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Old 04-10-2010, 07:17 PM   #3
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If you're blowing coils on your glow plugs, you are indeed running too lean. You should always tune by engine performance first, and temp second, which it sounds like you're trying to do. In this case, it seems like you needed to richen up the mix a bit. Without more details, it would be hard to tell if it's the low end or top end.

In a pinch, the "spit test" works well. Take a small drop of spit, and put it on your head. If it boils off immediately, your're too hot, if it just sits there and never really evaporates, then you're too cool. You want to to evaporate off in 2-3 seconds. Like I said, it's not an exact method, but it will give a general idea of how hot your motor is...
what other details would you need? i am very green when it comes to nitro cars but i can try to answer any questions you have to help me.

the engine was originally a pull start. i got rid of that and put a backplate on it and use a bumpstarter now. I also got rid of the stock pipe and picked up the OFNA 063 but after a couple runs realized it was leaking air. i have changed the rubber gasket on the engine to the header and the header to the pipe with a bit bigger one to seal it better. i ran it for a short period, on the box, not on the ground and saw there was a little fuel leaking at the plug. i tightened the plug down (left it too loose by mistake because i am scared to over tighten it. ) started the car and ran it in an oval race for about 3 minutes and it shut down.. I did get tangled up a couple times and rolled the car pretty hard. the car seems to bog just a touch when punching the throttle at lower speeds. once it runs out 10 ft or so it pulls real hard.

with the carb on this engine, i know the HSN screw but do not know what the other two screws are.. well, not true. the screw by the throttle linkage is to set the idle adjustment i am pretty sure. correct me if i am wrong and offer some more assistance if this helps.

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Old 04-10-2010, 08:00 PM   #4
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the car seems to bog just a touch when punching the throttle at lower speeds. once it runs out 10 ft or so it pulls real hard.

with the carb on this engine, i know the HSN screw but do not know what the other two screws are.. well, not true. the screw by the throttle linkage is to set the idle adjustment i am pretty sure. correct me if i am wrong and offer some more assistance if this helps.

ben
Sounds like you are too lean on the HSN and too rich on the LSN. The LSN will be the adjustment that is on the carb slide
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Old 04-11-2010, 12:17 AM   #5
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Other issues blowing plugs:

1) high compression (did you remove a headshim?)
2) play on the rod or bearing inside the engine
3) a to hot choosen plug.
4) to high nitro content.
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Old 04-11-2010, 04:31 AM   #6
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Other issues blowing plugs:

1) high compression (did you remove a headshim?)
2) play on the rod or bearing inside the engine
3) a to hot choosen plug.
4) to high nitro content.

roelof,

I have had the clutch off the car, nothing else. no headshim removal. i don't think that this is the issue. I cannot answer the second question. The third question i can say the o.s. plug i popped was a hot plug. the traxxas one i cannot recall if it was hot. should i try a medium? the nitro content i think is okay it is 20%. that is what the previous owner ran. i put 2/3 of a gallon on it before i started running into these problems. they have started since i put the back plate on the engine.
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Old 04-11-2010, 02:21 PM   #7
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roelof,

I have had the clutch off the car, nothing else. no headshim removal. i don't think that this is the issue. I cannot answer the second question. The third question i can say the o.s. plug i popped was a hot plug. the traxxas one i cannot recall if it was hot. should i try a medium? the nitro content i think is okay it is 20%. that is what the previous owner ran. i put 2/3 of a gallon on it before i started running into these problems. they have started since i put the back plate on the engine.
That's one of those pieces of information that's good to share up front...

Before you look at anything else, pull off that back plate and seal it up. An air leak will cause your tune to go all over the place. Go to your local hobby shop, and get some Lucky 7 sealant, and seal the back plate (In a pinch, O2 sensor safe silicone RTV from an auto parts store will work).

While you're waiting for the sealant to dry, if you haven't already done so, read the tuning bible that stickied at the top of this forum. I've found it very helpful...Here's another good article to look over too.... http://www.rchobbies.org/engine-tuning.htm

Try that, and let us know how it goes.
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