Fast .21 motor break-in

[modhobby]

Does anyone know the instructions, like the amount of time you run and the amount of fuel to run to break in a motor using the, run rich method at full throttle? I want to try that today if possible.

[josh35]

The way I do it is

I start with needles at factory settings
1st tank is start it let it idle to 160 degrees then rich it up two turns and hold the throttle open and let it cool to 120 degrees
Then fill the tank and set the needle back to the factory settings and let it idle to 170 degrees and then do the same as before Do the same process all the way to 200 degrees 10 degrees at a time all this with out turning it off.

Then drive for two or three tanks on the ground tuning it to what you want out of it watch your temps.

Adam Drake did a write up on this in one of the mag.

[modhobby]

I found this article:
www.cefx.net/tips/nitro/break-in/index.php

josh35 said:

The way I do it is

I start with needles at factory settings
1st tank is start it let it idle to 160 degrees then rich it up two turns and hold the throttle open and let it cool to 120 degrees
Then fill the tank and set the needle back to the factory settings and let it idle to 170 degrees and then do the same as before Do the same process all the way to 200 degrees 10 degrees at a time all this with out turning it off.

Then drive for two or three tanks on the ground tuning it to what you want out of it watch your temps.

Adam Drake did a write up on this in one of the mag.

[ilikef150s]

My thought is the WOT at cooler temps puts too much stress on the rod, but that's just me. Break-in methods are more religion than science.

It really depends on how "tight" the engine is as to what method I use. I had a Novarossi 528 that would not turn over until it was 140 deg (had to pre-heat it with a heat gun). Also, it took over a gallon before it was fully broken in. That engine ran a year and a half, with an average of two race days (2-3 heats and a main) per month.

On the other hand, this Sirio seemed like it was ready to go after six tanks, but still it didn't get a "full race tune" on it until it had run for about a gallon.

I use the "heat cycle" method. Blip the throttle on the stand until it gets up to 200 deg, then shut it off and move the piston to BDC. I do that for three or four times, then start running it on the ground a tank at a time, making sure the temp gets up to at least 180, but not over 250.

After about a gallon, I start tuning for smoke and performance, not really worying about the temps. An engine is gonna run at the temp its gonna run. If it's putting out good smoke, and doesn't sound like its lean bogging, then I don't wory too much about the temps.

Good luck!

[nolec5]

If you are going to do the WOT break in method, you need to have a heat gun on the block the entire time in order to keep heat in the engine. Even with the heat gun, at the end of the tank you will be lucky to have it stay above 150 degrees.

This method is not for the faint of heart. The last engine I did this way....I ran two tanks....WOT, super rich to where the tires were barely rolling on the box....with a heat gun on the block. Then race tuned. Engine is still going strong with at least 5-6 gallons on it.