Spark Gapping2 Cooling Power
This is the 2nd part with 2 kml Taps and 1 on the main starter coil. More power more gas gets eaten up. but you can increase the spark gap to a ...
James Burke : Connections, Episode 10, "Yesterday, Tomorrow and You" ...
pistol in the 18th century, what would you have made of it? An electric spark jumps across the gap between those two wires, and causes gasses ...
DAVID WILCOCK at the Project Camelot Awake and Aware Conference, Los Angeles, Sept ...
Hmmm, I wonder. That was purely subconscious. I have no idea what I'm doing there Or, I could go... No, there is no subtext. I'm not ...
Tuning the Traxxas TRX 3.3 Engine
First off, let me say you should follow the instructions both written and on the DVD that accompanied your model. The directions given by Traxxas will both help further your understanding of this machine and avoid the worst abuses you can otherwise unknowingly impart on your engine. What I write is no substitute for their information and should never be done until AFTER your completed break-in following the Traxxas break-in procedure. I also recognize there is a certain amount of gap between that information and a working understanding of how to tune your engine in the real world.
I was forced to learn a bit more about tuning because of the cold weather this winter and I wanted to take a chance on passing along what I have learned. First, a short lecture about what it takes to tune any engine. You’ll read about fuel mixtures and how to set those, idle speeds and settings, and other various things when it comes to tuning an engine. The fact is no one aspect exists in a vacuum but they all interact and affect each other. Don’t expect to get the best performance from an engine JUST by gapping the spark plugs or just adjusting timing or just changing fuel mixtures. You have to level set everything in rounds, check and readjust until you get everything set up right. Most mechanics will get everything in the ballpark and let it ride. In modern passenger vehicles, the computer is typically relied upon more to fine tune in real time, resulting in huge leaps of power and efficiency previously unobtainable. In the TRX 3.3, you have no computers, so you have to tune it old school.
There are five items you must be concerned with. These are (1) general running condition, (2) Factory settings, (3) high speed needle, (4) low speed needle and (5) idle air gap.
General Running Condition This references the condition of all the parts in and around the engine. The gas tank needs to be free of cracks or leaks. Check the O-ring around the lid and adjust it’s sealing properties using the alan head screw. Replace your glow plug without hesitation. Check all your fuel and pressure lines for splits or cracks. A roll-over accident can cut these lines pretty easily especially if running on asphalt or concrete. Check your exhaust system and the rubber connector between your pipe and your header. Make sure all these connections are sealed up tight and are cinched with zip ties. Clean your air filter and filter assembly. Re-oil the filter and get it back on the engine. Check the engine mounts for loose or missing screws. I’ll say here that the magnets in your EZ Start motor will attract loose engine mount screws. This is one demonstration of the fact that your success or failure will depend in part on how well you clean and inspect your model before and after running it. Check wire connections such as the block ground connection and the glow plug connector. Check mesh with the spur gear and make sure your transmission is properly seated and all of it’s screws are tight and present. Correct any issues you find in this area. I use a strip of notebook paper folded to double thickness as a way to set my spur gear mesh. If it’s tight with the notebook paper it will mesh perfectly when that paper is removed. A thicker paper doesn’t have to be folded in half. I wouldn’t use construction paper though. Basically what you want is a completely non-binding mesh such that when the teeth come into contact with each other their entire faces touch all the way across, transferring the most power possible from the output shaft of the engine to the input shaft of the transmission. Make sure the motor is squared perfectly and that the teeth mesh all the way across and not just on one side. Also check your throttle and brake linkages. Follow the directions from Traxxas to a “T” and you will not have issues. A fouled up linkage adjustment will cause your engine to act in unpredictable ways so do not ignore this part. Your internal engine components play a part as well, obviously, but I am assuming you have good compression and aren’t needing a rebuild. Once you are comfortable with the general condition of your rig, you can move on to the other steps. I highly recommend some sort of temperature monitor, either a infrared gun or the traxxas on-board temp gauge. The on-board monitor records the max, min and current temp so you can be sure you didn’t overheat during a run and just miss the peak temp by getting to your gun and checking. These engines cool very quickly from their peak temp. Bear in mind that your real goal is to make sure you aren’t overheating. There is no set temperature you should run at, but in general you don’t want to see the max temp rise above 270. I’ve seen mine hit over 300-311 when I had an issue… but when things are right, I see it around 230-240. It doesn’t start running right until it’s over about 150-160 though. The temp gauge helps ensure you don’t fry your engine and get to start over with a new one. Something you may want to check periodically is your clutch bell bearings and clutch shoes/springs. These things do wear out eventually and need to be replaced. I have heard of people replacing these things every 2 gallons of fuel run through their engine. I have replaced my bearings once and my engine has 1 gallon on it, almost. I replaced mine with sealed bearings, so they should last longer this time around. Put your engine in a large zip lock back before you take off the E-clip holding on the bell housing. That way you won’t lose it when it shoots off. If you are careful it won’t shoot off anyway, but better safe than sorry. Hey, be sure to trim all zip ties prior to running your engine. You don’t want these getting in the way of moving parts or getting snagged by a wheel or something in your operating environment.
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