Nitro Engine Break-In Procedure Articles

Nitro Engine Break-In Procedure

Thanks for sharing...

There are many different ways to break-in a nitro engine. Here’s the procedure I use for all my engines.

The best place to break-in an engine is a wide parking lot, always keep your vehicle near you.

Things to do before starting your engine for the first time:

Inspect the engine for any loose screws, specially the back plate and the carb.

Make sure that the throttle servo trim is correctly adjusted.

Oil the air filter.

Remove the glow plug and I put few drops of after run oil into the combustion chamber and I manually turn the crankshaft to make sure the engine will not start “dry”.

Things to know before tuning your engine:

Locate the adjusting screws on your carb.

Nitro Engine Break-In Procedure Articles
Pay close attention. On this Monster GT .28 engine. The low speed needle is on the opposite side where normally the middle speed needle is located.
Nitro Engine Break-In Procedure Articles
Here is a typical two-needle carburetor

Nitro Engine Break-In Procedure Articles   Remember, when you lean your engine, only turn 1/16 turn clockwise at the time.

Nitro Engine Break-In Procedure Articles   Remember, when you richen your engine, only turn 1/16 turn counter clockwise at the time.

Tank #What to do
1
  • Prime the engine until fuel reach the carb.
  • Install the glow plug starter and start the engine.
  • Once the engine is started make sure that it is running on the rich side. Let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run your vehicle at low speed, don’t exceed 1/4 throttle. Go straight and do wide turns. Don’t try to break speed record.
  • Frequently verify the engine temp.
  • After 2-3 minutes, engine temperature should be between 195F and 205F. If the temp is below, turn clockwise the high speed needle 1/16 turn. If the temp is above, turn counter clockwise the high speed needle 1/16 turn.
  • Run your vehicle until the fuel tank is almost empty. Stop the engine before the fuel tank is empty to prevent your engine from running lean.
  • Be sure the piston is at BDC (Bottom Dead Center). This means that the piston is at the bottom of the cylinder.
  • Let your engine cool for 10-15 minutes.
2
  • Install the glow plug starter and start the engine.
  • Once the engine is started, let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run your vehicle at low speed, don’t exceed 1/2 throttle. Go straight and do wide turns. Don’t try to break speed record.
  • Frequently verify the engine temp.
  • After 2-3 minutes, engine temperature should be between 195F and 205F. If the temp is below, turn clockwise the high speed needle 1/16 turn. If the temp is above, turn counter clockwise the high speed needle 1/16 turn.
  • Run your vehicle until the fuel tank is almost empty. Stop the engine before the fuel tank is empty to prevent your engine from running lean.
  • Be sure the piston is at BDC (Bottom Dead Center). This means that the piston is at the bottom of the cylinder.
  • Let your engine cool for 10-15 minutes.
3
  • Turn the high speed needle 1/16 turn clockwise to lean the engine.
  • Install the glow plug starter and start the engine.
  • Once the engine is started, let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run your vehicle but don’t exceed 3/4 throttle. Go straight and do wide turns. Don’t try to break speed record.
  • Frequently verify the engine temp.
  • After 2-3 minutes, engine temperature should be between 205F and 220F. If the temp is below, turn clockwise the high speed needle 1/16 turn. If the temp is above, turn counter clockwise the high speed needle 1/16 turn.
  • Run your vehicle until the fuel tank is almost empty. Stop the engine before the fuel tank is empty to prevent your engine from running lean.
  • Be sure the piston is at BDC (Bottom Dead Center). This means that the piston is at the bottom of the cylinder.
  • Let your engine cool for 10-15 minutes.
4
  • Turn the high speed needle 1/8 turn clockwise to lean the engine.
  • Install the glow plug starter and start the engine.
  • Once the engine is started, let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run your vehicle, don’t exceed 3/4 throttle. Go straight and do wide turns. Don’t try to break speed record.
  • Frequently verify the engine temp.
  • After 2-3 minutes, engine temperature should be between 205F and 220F. If the temp is below, turn clockwise the high speed needle 1/16 turn. If the temp is above, turn counter clockwise the high speed needle 1/16 turn.
  • Run your vehicle until the fuel tank is almost empty. Stop the engine before the fuel tank is empty to prevent your engine from running lean.
  • Be sure the piston is at BDC (Bottom Dead Center). This means that the piston is at the bottom of the cylinder.
  • Let your engine cool for 10-15 minutes.
5
  • Turn the high speed needle 1/8 turn clockwise to lean the engine.
  • Install the glow plug starter and start the engine.
  • Once the engine is started, let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run your vehicle, you can go full throttle for very short time, only few seconds (2-3). Go straight and do wide turns. Don’t try to break speed record.
  • Frequently verify the engine temp.
  • After 2-3 minutes, engine temperature should be between 210F and 225F. If the temp is below, turn clockwise the high speed needle 1/16 turn. If the temp is above, turn counter clockwise the high speed needle 1/16 turn.
  • Run your vehicle until the fuel tank is almost empty. Stop the engine before the fuel tank is empty to prevent your engine from running lean.
  • Be sure the piston is at BDC (Bottom Dead Center). This means that the piston is at the bottom of the cylinder.
  • Let your engine cool for 10-15 minutes.
6
  • Turn the high speed needle 1/8 turn clockwise to lean the engine.
  • Install the glow plug starter and start the engine.
  • Once the engine is started, let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run your vehicle, you can go full throttle for very short time, only few seconds (2-3). Go straight and do wide turns. Don’t try to break speed record.
  • Frequently verify the engine temp.
  • After 2-3 minutes, engine temperature should be between 210F and 225F. If the temp is below, turn clockwise the high speed needle 1/16 turn. If the temp is above, turn counter clockwise the high speed needle 1/16 turn.
  • Run your vehicle until the fuel tank is almost empty. Stop the engine before the fuel tank is empty to prevent your engine from running lean.
  • Be sure the piston is at BDC (Bottom Dead Center). This means that the piston is at the bottom of the cylinder.
  • Let your engine cool for 10-15 minutes.

With six tanks burnt, your engine is almost broken-in. Now follow the next steps to complete and set your engine for optimal performance.

It’s now time to set the high speed needle.

7
  • Install the glow plug starter and start the engine.
  • Once the engine is started, let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run at mid speed to let the engine warm up. The temp should be between 210F and 230F.
  • Frequently verify the engine temp.
  • Do some high speed passes. A light blue smoke should come out the tuned pipe while full throttle. If there is no smoke, richen the high speed needle. If the engine can’t rev high enough and there is a lot of smoke coming out of the tuned pipe, lean the high speed needle. Always check the engine temp after high speed passes. If the engine is too hot, richen the high speed needle. If the engine is too cold, lean the high speed needle. Optimal temperature vary depending of your engine brand. Normally, optimal operating temperature should be between 230F and 250F. I never exceed 250F. Keep in mind that depending of the outside temperature and atmospheric pressure, your engine’s temp and performance will vary.

It’s now time to adjust the low speed needle

8
  • Install the glow plug starter and start the engine.
  • Once the engine is started, let the engine idle for few seconds, if the engine seems to die, give a little blip on the throttle.
  • Run at mid speed to let the engine warm up. Always tune an engine when hot.
  • Frequently verify the engine temp.
  • Let your engine idles for 30 seconds and then peg the throttle. If your engine hesitates to rev up, lean the low speed needle. If your engine quickly accelerates with no smoke coming out of the tuned pipe, richen the low speed needle. Always richen or lean the low speed needle 1/16 turn at the time.
  • A good trick to adjust the low speed needle is to let the engine warm and pinch the fuel line at 1 inch from the carb. The engine should lightly rev up for 3-4 seconds and then die.

Sylvain Lafrance

Hello, my name is Sylvain Lafrance and I am the man behind MyRCBox.com. I have bought my first hobby grade RC in the early 90s. With years, what that started as a simple hobby, quickly became a strong passion. I am so much passionate about R/C that I have created MyRCBox.com in 2006 to share my experiences with R/C products that I use for racing and bashing. Follow me !

This Post Has 6 Comments

  1. Avatar

    correct.. there’re many ways to break or run-in your engine. There’s no single like the one and only way to do it. one thing for sure, check the temp not over the limit. Mine always below 90C and I am using Josh Cyrul style, the WOT style. I did on my 5 engines and none that I have to replace the conrod afterwards. On all five engines, 2 novas, 1 go 7p and 2 sts offroad engines.. all still working till today.

    thanks for sharing this article. 🙂

  2. Avatar

    The needle marked low speed is actually the middle or “Mix Metering” needle. the low speed needle is on the other side of the carb in the middle of the slide.

  3. admin

    You’re half right. The low speed needle shown here is the correct one because the engine used for the picture is a Team Associated .28 engine from a Monster GT. The low speed needle is located on the opposite side of “normal” carburetor. Here is a picture of the other side of the engine.

    Thanks for your comment, I’ll update the picture with a new one to make things clearer.

  4. Avatar

    Hi regarding the pinch test,i pinch the fuel line with a clamp right near the carb nipple,my engine runs for 2 seconds and then rpm pickes up very high,making the total 5 seconds before it quits,is that a sign of to rich,thanx
    Regards DD

    1. admin

      f the low speed needle is set correctly, the engine should increase rpm only slightly and then die.

      If the engine increases several hundred rpm before dying, then the low speed needle is too rich and needs to be turned in.

      If the rpm doesn’t increase at all and the engine simply dies, the low speed needle is set too lean and should be richened or turned out.

  5. Avatar

    Good post. I learn something new and challenging on sites I stumbleupon every day.
    It’s always interesting to read content from other writers and use something from their sites.

Leave a Reply to admin Cancel reply

*

Close Menu