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Old 01-07-2003, 01:48 PM   #1
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Default break in an engin

does anyone know how to break in an engine .21
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Old 01-07-2003, 02:53 PM   #2
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This subject has been covered before, and everyone has their own method of break-in. The break-in method for any .21 engine is the same as any nitro engine. I found the best method of break in is the first runs of the engine should be short, about 3 or 4 mins at idle with the wheels off the ground. Do this for the first 4 runs of the engine. Now you can run fulltanks at about 1/2 to 3/4 throttle for 4 more tanks. Now you can start to lean it out. Before you break-in the engine, take the glow plug out, and put about 5 or 6 drops of after run oil in the engine, replace the glow plug and trun the enginer over for a second. Also for .21 engines use 20% nitro or better. Hope this helps.
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Old 01-08-2003, 01:35 PM   #3
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how long should i wait inbetween each run before i cant run it again to break it in. should i jusu hold up the wheels so they don't touch the ground
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Old 01-08-2003, 03:41 PM   #4
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i do it differently

first set needles to base setting provided by manufacturer or if none provided i will turn needles out some both high and low

second i set my radio end point adjustment to 50% throttle opening

third i start engine and drive my car for a minute if it isnt too rich to run

forth i tune high end needle till 200F or close 190-200 i will run 8-10 tanks at this setting using short bursts of throttle (no more than 50%) for no more than 3 seconds

fifth i am done its time to turn throttle to 100% carb opening and check performance and tune it till max performance is reached

i have done engines both ways and id sware the engines ive done this way run faster and i dont have to stand around waiting for car to idle through tanks i get to play the entire time
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Old 01-08-2003, 04:04 PM   #5
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You only have to let it cool for a minute or two between the first few runs, when running full tanks let cool about 5 minutes. The whole process should take you about 1 1/2 hours including tuning.
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Old 01-08-2003, 05:56 PM   #6
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thanx
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Old 01-09-2003, 08:18 AM   #7
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I have to disagree with your break-in method's. First and for most you should dis-assemble the engine and check for any small burrs or other small pieces of machining that might have been missed during assembly at the manufacturer. After inspection is done, use some Blaster (more on this at the end of my post) on all the internal parts. use RTV "sensor safe" silicone to seal everything. Back plate, carb to case, pinch bolt for the carb and if it has a boost chamber, the fittings for that as well.

Next step would be to add fuel, you'll want to prime the engine BEFORE you turn the engine over. You can do this by blowing into the exhaust until you see fuel going through the fuel line into the carb. Now your ready to turn it over. The next step is VERY important, you'll need to heat cycle the engine at least 4 times. What does heat cycling do?? It expands and retracts the case, p/s, head, and all internal parts. This is important to do because the metal can change it's shape or distort ever so little on the first few times it is heated up. The metal can disfigure or change it's shape the first few times it is initally heated. After the engine has been heateda few times it will maintain or won't change anymore, but will on the first few runs. If you don't heat cycle, the metal doesn't "find" it's final shape and will cause more wear as your breaking it in.

What you want to do is run the engine for enough time to reach about 200 degrees then shut the engine off and turn the flywheel until you've reached "bottom" dead center. At this point you need to let the engine "completely" cool down. Once cooled off, start engine and bring up to 200 again. repeat this 4 times.


After your finished heat cycling the engine your ready to start driving the car at a pretty rich setting. You will have to change the needle setting. You'll want the engine to be 4 stroking or at 40-50% power (rich enough so it won't clear out). Run it like this for 3-4 tanks. You can pull 50-75% throttle as long as the engine doesn't rev up much. After the 4th tank you can start to lean it out until your close to 60-70% power. You can run the engine at this setting for a 2-3 tanks. Once you've reach this point you can set the high end needle to optimum power or so temp is good. 220max. THEN the low end needle.


I've been doing all my engines like this for years and they always have ran great and had good compression after 6-7 gallons. My latest is a O.S. V01B and after only 1 gallon I've seen the temp going down and the power going up. On my last run my buddy checked the temp and it was 210 and bottomend was insane, topend was as fast as any car on the track. CRCRC in Ohio.

I use 30% Trinity Platinum with some castor oil added.

One thing I've been using is PB Blaster. It displaces moisture, remains on the metal surfaces and helps restore or maintain rubber seal's and "o" rings. What I do is, spray a shot in the tanks BEFORE I break-in an engine so it will mix with the fuel for the first few heat cycles. I also use it in place of after-run oil. It acually works better then off the shelf after-run oil because it displaces moisture!!!! After-run oil doesn't, it only coats the parts to try and protect them from rust. You should try some, I think you'll find the results astounding!!! You can find it in the automotive section at Walmart...


Hope this helps...

Last edited by GregH; 01-09-2003 at 08:36 AM.
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Old 01-09-2003, 12:38 PM   #8
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Default Engines

I'm new to RC cars. It was kinda shocking to hear and read that some people break in engines with no load. I figured maybe this was just unique to the lil glow engines.

I've always broken in engines under the following basic rules

1. Warm up the engine. (Cylinder warm to the touch, with liquid cooled engine...probably not necessary with these, 30 seconds s/b good)
2. Low RPM (increasing max % throttle is opened a little each new heat cycle)
3. Varied RPM
4. Under a load (helps the parts seat against each other)

3-4 heat cycles. Looks like 4-5 is what I hear when it comes to these lil engines (prob cause of smaller gas tanks). Running with the tires in the air (no load) and not letting the engine cool between tanks kinda flew in the face of all conventional engine break-in procedures I was used to. Albiet they are a different type of engine from what I was used to.

I'm glad to hear others break in engines similar to how I have broke in other single cylinder 2 stroke engines that zing up to 14k rpm. Not sure what these lil motors turn yet, still new to em.

To the previous poster, how bad are the burs from the factory? Nice tips, thanks.
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Old 01-11-2003, 10:02 AM   #9
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I've only seen burrs or very small machining material in 1 engine. It was a T/Picco .12

You could heat cycle the engine out of the car as well, by putting it in the oven. It takes alot longer though to heat up the inside of the engine because you don't want the oven more then 220 degrees. It would take at least 15 minutes or more to get the internal's heated up enough. All your trying to do is get the engine up to about 180-200 so the metal will expand. Much less then 180 and it won't expand fully. That's why I use the PB blaster before I start the engine. It helps stop some of the wear, while trying to heat cycle.
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