Super Tigre G27 CX getting hot
04-05-2007, 08:13 PM
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Super Tigre G27 CX getting hot
Hello,
I have 2 ST G27 CX motors and am having the same problem with both of them. I would really appreciate some help in getting the wrinkles ironed out.
The problem: While tuning the motors I run into the same issues. Tuning the HSN for crisp power with good smoke came out to about 4-1/8th turns out. This is where it runs the strongest allows the transmission to shift and stays around 250-270 degrees mid tank. Now as the tank goes to about 1/4th the thing heats up, and once it starts to go over 270 it will sky rocket to 300 even after adding fuel to the tank. What happens when it gets over 270ish is that the rpms pick up even more all across the board and even putting around slow causes more and more heat buildup. I stop the motor and let it cool down to about 200 richen up the HSN by 1/12 of a turn and now it won't warm up above 220ish. At 220 it's a pig and won't build enough rpms to shift and sounds muffled while putting around at jogging pace... I ran this thing for an entire tank and it didn't start to come alive until the tank was below 1/4 and started to lean itself out, I added gas and it went right back to bogging around.
This really confuses me since I only turn the needle 1/12th of a turn OUT and it went from overheating to not getting to the 250 degree operating temp at all. I try turning it back IN 1/12th of a turn and it went right back to overheating at anything between 1/3rd and 1/4 tank.
The LSN was set after getting the HSN set and I used the pinch test. Pinch the line off and it runs for 2 seconds or so, revs a bit then dies. This came out to 11-2/3rds turns OUT on the LSN with the throttle wide open. Idle later set to minimum reliable speed.
I have been making all of my adjustments in 1/12th turn increments and running 100 yards or so in between each adjustment.
One truck is on Trinity Monster 20% with the Duratrax Gold Plug.
The other truck is on Traxxas 20% with the stock plug that came in the motor.
It confuses me furthing since I have 2 trucks with the same motors and they both exhibit the same tendencies, I figured if one had a problem the other would have been fine. It seems once you tick over that 270 mark they shoot up rapidly in temp. I know that's supposed to be the max operating temp and the closest I can get is between 250-270 up to 1/2 tank of gas, then it's going Chernobyl on me after that. I've tried testing with the body on and off and it's pretty close in temp, I have air holes in them. I can't imagine them being this touchy since most other motors are relatively easy to at least get in the ballpark. I have read of some people saying the carb leaks air between itself and the manifold. That they replace the o-ring and put some gasket sealer around it to seal it up. Is this something I should have to do? These things have been broken in and run a few days after that just trying to tune them. They are still new in my eyes.
What am I overlooking?
Any advice would be greatly appreciated
Chris
I have 2 ST G27 CX motors and am having the same problem with both of them. I would really appreciate some help in getting the wrinkles ironed out.
The problem: While tuning the motors I run into the same issues. Tuning the HSN for crisp power with good smoke came out to about 4-1/8th turns out. This is where it runs the strongest allows the transmission to shift and stays around 250-270 degrees mid tank. Now as the tank goes to about 1/4th the thing heats up, and once it starts to go over 270 it will sky rocket to 300 even after adding fuel to the tank. What happens when it gets over 270ish is that the rpms pick up even more all across the board and even putting around slow causes more and more heat buildup. I stop the motor and let it cool down to about 200 richen up the HSN by 1/12 of a turn and now it won't warm up above 220ish. At 220 it's a pig and won't build enough rpms to shift and sounds muffled while putting around at jogging pace... I ran this thing for an entire tank and it didn't start to come alive until the tank was below 1/4 and started to lean itself out, I added gas and it went right back to bogging around.
This really confuses me since I only turn the needle 1/12th of a turn OUT and it went from overheating to not getting to the 250 degree operating temp at all. I try turning it back IN 1/12th of a turn and it went right back to overheating at anything between 1/3rd and 1/4 tank.
The LSN was set after getting the HSN set and I used the pinch test. Pinch the line off and it runs for 2 seconds or so, revs a bit then dies. This came out to 11-2/3rds turns OUT on the LSN with the throttle wide open. Idle later set to minimum reliable speed.
I have been making all of my adjustments in 1/12th turn increments and running 100 yards or so in between each adjustment.
One truck is on Trinity Monster 20% with the Duratrax Gold Plug.
The other truck is on Traxxas 20% with the stock plug that came in the motor.
It confuses me furthing since I have 2 trucks with the same motors and they both exhibit the same tendencies, I figured if one had a problem the other would have been fine. It seems once you tick over that 270 mark they shoot up rapidly in temp. I know that's supposed to be the max operating temp and the closest I can get is between 250-270 up to 1/2 tank of gas, then it's going Chernobyl on me after that. I've tried testing with the body on and off and it's pretty close in temp, I have air holes in them. I can't imagine them being this touchy since most other motors are relatively easy to at least get in the ballpark. I have read of some people saying the carb leaks air between itself and the manifold. That they replace the o-ring and put some gasket sealer around it to seal it up. Is this something I should have to do? These things have been broken in and run a few days after that just trying to tune them. They are still new in my eyes.
What am I overlooking?
Any advice would be greatly appreciated
Chris
04-06-2007, 10:04 AM
#2
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RE: Super Tigre G27 CX getting hot
If the engine is running well and is not going lean beyond peak RPM, then ignore the temperature. How the engine is running is more important. If it will accelerate up to full throttle and hold without sagging in RPM, you're not too lean. We've never, ever, worried about engine temperature. We listen to it and watch it. We don't even worry much about smoke. An engine can be too lean and still make a lot of smoke, depending upon the fuel.
Over-reliance on temperature has shortened the life of many an engine. You need to get the engine set up to be running correctly first, and then only use temperature as a guide to how the engine's running. If it's running well, then you MUST accept the temps you get, no matter what anybody says. Running well is the priority.
Here's what we tell people when they ask us about engine temps:
It's not possible for us to give you an actual temperature or temperature range for your engine. The specific temperature is determined by too many factors. There is only one way to determine at what temperature your engine should be run. You have to run it first and then find out what temperature the engine reaches.
Make sure your engine is operating properly with the performance you expect. Use the exact setup every time...fuel, exhaust system, plug, measurement location, and so forth. If you change anything, the temperature will change. Once you have the engine running the way you want it. Take your measurement. This is your starting point. You will have to take measurements over time to find out how the weather affects it. As the air temperature and humidity change from day-to-day, the operating temperature will change. Eventually, you'll find a temperature range that you can work with.
Engine temperature is not an absolute number for setting your engine. It is only a guide, and can help alert you to potential problems. The only sure way to make sure your engine is running correctly is to see how it's running. An engine can be operating at "correct" temperatures, but not running well.
Finally, use any temperatures you read about, or people tell you, as rough information. The only useful numbers are the ones you actually measure when your engine is running correctly. If your engine is running correctly, then what you measure is correct, even if some else says it's too high or too low. Don't worry about the differences. Each engine is in a unique installation with a unique set of circumstances, so there can be wide variances in engine temperature.
Over-reliance on temperature has shortened the life of many an engine. You need to get the engine set up to be running correctly first, and then only use temperature as a guide to how the engine's running. If it's running well, then you MUST accept the temps you get, no matter what anybody says. Running well is the priority.
Here's what we tell people when they ask us about engine temps:
It's not possible for us to give you an actual temperature or temperature range for your engine. The specific temperature is determined by too many factors. There is only one way to determine at what temperature your engine should be run. You have to run it first and then find out what temperature the engine reaches.
Make sure your engine is operating properly with the performance you expect. Use the exact setup every time...fuel, exhaust system, plug, measurement location, and so forth. If you change anything, the temperature will change. Once you have the engine running the way you want it. Take your measurement. This is your starting point. You will have to take measurements over time to find out how the weather affects it. As the air temperature and humidity change from day-to-day, the operating temperature will change. Eventually, you'll find a temperature range that you can work with.
Engine temperature is not an absolute number for setting your engine. It is only a guide, and can help alert you to potential problems. The only sure way to make sure your engine is running correctly is to see how it's running. An engine can be operating at "correct" temperatures, but not running well.
Finally, use any temperatures you read about, or people tell you, as rough information. The only useful numbers are the ones you actually measure when your engine is running correctly. If your engine is running correctly, then what you measure is correct, even if some else says it's too high or too low. Don't worry about the differences. Each engine is in a unique installation with a unique set of circumstances, so there can be wide variances in engine temperature.
04-06-2007, 10:55 AM
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RE: Super Tigre G27 CX getting hot
Thanks for the fast response. Oh yeah they will run up to full throttle and hold... honestly they both run better once they hit that temp spike but I notice that when returned to idle at this higher temp they tend to run higher. At the 250 mark they pass a pinch test fine, but at 270+ the sound changes and they sound.... angry... instead of a nice steady idle ba ba ba ba ba ba it turns to a high low BA ba BA ba BA BA ba and sounds more erradic and the spur gear is a-rockin. I tried adjusting the idle down a tad, but then the truck will stall at idle on anything less than 270 degrees. I guess I'll richen up the LSN once it spikes and see if that takes care of it. I know the trucks are both close, I just got worried when the manual says DANGER DANGER do not exceed 270 degrees especially when they didn't seem to wake up until that temp.
Thanks again,
Chris
Thanks again,
Chris
