OK Folks, keep in mind the purpose of this thread- to help people break in an engine correctly.
Now, I will go over it quote by quote on what is and is not the correct method of break ing in an RC Car nitro engine .
1. Before starting a brand new engine , take out the glow plug, take off the carb, and take off the backplate (this will not void your warranty) and with great care not to splash it around, rince the engine insides with glow fuel or kerosene or another suitable solvent. Flush the carb and the cylinder as well, rotate the engine over by hand a time or two. This gets a lot of the metalic dust out of the engine that has been left over from the manufacturing. You will be surprised on how much metalic dust comes out of some engine s. Is it necessary? I think so for longevity reasons. Dry it off and lube it up with some castor oil or after run oil or even a little good ole motor oil. Reassemble engine and install it in the car.
Mark an arrow with permanent marker where your Top Dead Center is on your flywheel. This will help you in determining your Bottom Dead Center.
This is not necessary nor does not hurt anything. Remember that top dead center is when you turn the flywheel against great resistance (the pinch) and then it all of a sudden has slack in it.
Adjust all your linkages and radio/ throttle barrel, do your plumbing etc.
Always check and set the high speed and low speed needles according to the instructions, they are sometimes not set correctly at the factory.
Put fuel in tank, get it primed, etc
3. Preheat the top of the cylinder to relieve some of the pinch. A hair dryer might do it but it does need to get a lot hotter than a hairdryer will get, but anything will help here. Make sure you throughly heat it up.
Put on your glow driver and fire it up
.... allow the plug warmer to camp on the glow plug for an extra 5 seconds. Give it some small amounts of throttle in order to keep the car alive (donβt panic if the car dies, just start it up again).
You need to leave the glow driver on there and keep it running with the throttle, do not be afraid to spike it a bit to keep it running and getting it warmed up. Hold a nice real high idle and take off the glow driver. If it stalls when removed, its either too rich or the plug is bad. Start it back up.
Once it stays running you need to allow the car to βFree Idleβ for one whole tank of gas. This means that you need to get rid of all forces working against the engine by placing the center of the car on an object that is above the ground allowing the wheels to spin freely (Hence the name βFree Idleβ). Run it a little over idle and donβt allow the engine to heat up much. Try keeping it under 1/4 throttle. Run it like this for 2 more tanks of gas, allowing a ten-minute break in between the tanks.
Absoutly wrong unless you want to be buying pistons and sleeves long before you realy need to.
Once it will start and run without the glow driver on, let the wheels freewheel and hit the throttle. If the engine is stumbling and not cleaning out to run at high speed throttle, lean out the high speed needle just enough to allow it to run in a nice clean mode. As soon as it will run clean, put it on the ground, and run it around. Do not just putt around at a low throttle, drive it!!!, take it to full throttle for very short periods and varying throttle positions. you may have to pit real quick to adjust the needle so its not so rich that it will not clean out during transition. Run it for two to three minutes and then bring it in and shut it down to cool completly to ambient tempreture.
6. Start it up once cooled off and do it again. Repeat the procedure (heat cycling) a minimum of three times but I really prefer the first 15 minutes of the engine s life is nothing but heat cycling. After the first run, you will probably need to start tweeking the low speed needle a bit and the high speed a bit as well, start driving it harder and harder each run. You can accelerate the cooling by holding the hair dryer over it set to just blow air but DO NOT SHOCK COOL IT WITH FUEL OR ALCOHOL during the break in heat cycling time.
Make sure you pay attention to the noise the engine is making and the smoke the exhaust pipe is producing If the engine sounds like it is making a screaming sound and the exhaust is only producing little or no smoke then the carb is set too lean and you need to turn the needle 1/8 turn toward open. If the engine is making a boggy sound and there is a thick trail of smoke then the carb is too rich and you need to turn the needle 1/8 of the way opposite of before.
Forget about the smoke and use your ears. I say this because the oil quality and type in the fuel is different for every manufacturer and some fuels smoke very very little making it hard to use that as a tuning tool. Yor ears are the most important tool you have.
If it is burburly from an idle, lean it out about an eighth of a turn at a time untill it spools up crisp and clean off an idle. Of course you can not do this on a cold engine , only tune on a fully warmed up engine . You will not need a temp gun either.
8. When you're done running for the day, pinch the fuel line and let the engine die from starvation, never flood it out by putting your finger over the exhaust. If you have wet fuel in the crankcase, it will absorbe moisture and potentially rust up bearings and the crankshaft. Run it dry and that way little if any liquid fuel is left in the engine to pull moisture in. Use an after run if you like.
....keep it there for 3 minutes running at no more than 1/4 throttle. Now shut down the engine , put the piston to BDC and let it cool completely. Do this over and over until you have around 25 minutes of runtime on the engine and then repeat it all over again but going up to 1/2 throttle. After the next 25 minutes is passed your engine should be nicely broken in.
This is not completly necessary. You can run it up to full throttle for short periods during the first couple heat cycling runs, it only helps. 25 minutes of heat cycling anything will not hurt it one bit, but no need exists to restrain yourself to 1/4 or 1/2 throttle in break ing it in. Getting the thing to operating temp is the critical thing (not too rich and not too lean).
.....NEVER tell a newbie to start off at full throttle. You never want to do anything other than brief bursts of WOT. 3-5 seconds at the most...unless you like broken conrods and shot bearings. Sure you can do high speed passes, but not full on WOT for extended periods of time.
Absoutly correct, although the bearings are unaffected by throttle and the con rods will only get tossed when the engine is running so rich athat the piston is being pinched in the sleeve top and stressing the rod too much. yet another reason not to run these things too rich.
.....Follow the damn manufacturs instructions. Good practice is heat cycling, and cooling with piston at BDC. Common is running rich, and running blips at full throttle.
Yes, heat cycling is good. Most people get in trouble by reading the instructions because most of the instructions I have read are completly incorrect on how to break in the engine s. Recently I read the Fantom instructions and they are right on target. Use the instructions for what the needle settings should be and other generic issues.
.....Yeah, different engine s require different break ins. I use this as a rule though: if the manufacturer says use 4 tanks to break in, I use 8. If the manufacturer says use 9 tanks, I use 13. Basically the 4 tanks after the manufacturers recommended break in, I would still run it easy and slow.
Yes, different engine s do require different break in procedures. For iexample- Ringed engine s are broken in completly differently than I describe, and so are lapped iron piston and sleeve engine s, ABC/ABN/AAC engine s are broken in like I describe.
Last I knew, all rc car and truck engine s were of the ABC type and therefore can be broken in the way I describe. Brand name of engine does not matter, car, truck, airplane, boat, if its an ABC type, it can be broken in the same.
Here's my disclaimer- I do this for a living, run engine s and try to destroy them, every way imaginable. I also try to see how long an engine will last when everything is done right. I've been doing this for a long time with airplanes, cars, helicopters and boats.
I do not sell parts, I do not make engine s, I do not own a hobby shop. I do not have any insurable intrest in making a profit from selling parts, therefore I have no reason to have you break in an engine in a manner harmfull to the longevity of the engine . I make fuel guys, and have every reason for you to have a good running engine that lasts a long time so you use and buy lots of fuel. I make no money when my customers are waiting for engine parts or waiting for somebody to fix it.
Hope this helps.