Engine Break In

For in car break in: 

1.) Warm the engine with a heat gun until it is (around 230F) before starting. This ensures a stree free first start.

2.) Start the engine. Then establish a rich steady idle, and let the engine idle for 30 minutes, then let the engine cool to ambient temperature. ****Always make sure the piston is at bottom dead center when the engine is turned off. Running temperatures during this stage will be between 180-220 degrees F. 

3.) Next, drive the car at a very rich setting for 3 full tanks. Make sure the car is very slow at full throttle, and lots of smoke at this stage.(Rich)  If the engine wants to rev quickly at this stage richen the main needle until the engine makes lots of smoke, but does not move fast, even at full throttle.  Let the engine completely cool again. Running temperatures during this stage will be between 180-200 degrees F. 

4.) Next, drive the car at a moderately rich setting for 3 full tanks. Make sure to use smooth throttle inputs. Quick, stabbing of the throttle at this stage will likely cause damage. Running temperatures during this stage will likely be between 200-240 degrees F.

5.) Over the next 10 tanks of fuel you can gradually lean the high speed needle. A good method to keep in mind is to go one hour leaner per tank of fuel to be safe. The engine will need to be run at a race setting in order to become fully broken in. Each engine will break in at a different time, and with a different amount of fuel due to differences in manufacturing materials, tolerances, fuels etc... You can know that the engine has fully broken in when you are running the engine at 90-95% of it's potential, and you can run at this pace without the engine going rich. An engine that is not fully broken in will continue to richen itself on the racetrack. 

An engine that is properly and fully broken in will reward you with cooler temperatures, more power, and long engine life. 

For Break in using a propeller:

*** Even a very small difference in size, or pitch of the break in propeller makes a difference. The numbers, and temperatures are based on the standard Hudy break in propeller.  For example, a propeller with more pitch, will cause less rpm, and more heat.  Sometimes it is a good idea to use a larger prop to keep the rpm under control***

*** For breakin we use the following fuel blend.  Nitro 10%, Castor Oil 14%, Synthetic Oil 2%***

***Always keep the cooling head covered so the airflow does now cool the engine too much.***

1.) Warm the engine with a heat gun until it is (around 200F). 

2.) Start the engine. Then establish a rich high idle ( around 9,000 r.p.m.) and let the engine run for 5 minutes. Then with the engine running at a very rich setting go to full throttle. Let the engine run at full throttle for 15 minutes at this very rich setting. Maximum R.P.M. should be around 16,000. Temperature should be around 200 F. Then let the engine gradually cool for 30 minutes.

3.) Slowly warm up the engine, and go to full throttle at a very rich setting. Then start to lean the main needle until the rpm increases, and the temperature stabalizes around 225F.. Run the engine like this for 30 minutes, then let cool for 30 minutes. Maximum rpm during this stage should be around 20,000.

4.) Slowly warm up the engine, and go to full throttle at a very rich setting. Then start to lean the main needle until rpm increases, and temperature stabalizes around 250F. Maximum rpm during this stage will be between 25,000 -30.000 rpm. Let the engine run like this for 20 minutes.

After this process has been completed on the break in bench, it is time to install the engine in the car.  The engine will only need one tank moderately rich, and then you can start tuning for maximum power.