Engine break in method
05-08-2006, 11:35 AM
#1
Tech Regular
Thread Starter
Engine break in method
I have a rb concepts S5 what's a good way to break in? please tell how you break in your engine?
05-08-2006, 11:57 AM
#2
Tech Adept
This was copied from a post by STEPHEN BESS on the "Starting Grid" message board as he tried to help another member get more life and performance out of his OS motor. This break-in method should apply to virtually any ABC hobby nitro engine (except for ringed engines).
If you are still idling at least a tank through during break-in, you're using the old-school accepted method (still works well for some!) but it's not the method that the top engine guys (Ron Paris, Dennis Richey, Rody Roem, Michael Salven are just a few I've spoken personally with about this) recommend anymore.
From the very 1st time you start your engine, plop the car on the ground & begin running it in a parking lot in 2-3 minute intervals, tuned only *slightly rich* getting the temps up in the 200F range on a normal day. Every 2-3 minutes, shut the engine down & let it cool completely with the piston at BDC, and then fire it back up; continue this cycle until you've run 15 min or so, and then bump up to 3-4 minute intervals. Vary the RPM and don't be afraid to get the temps in the 200's. What you want is heat cycling of the components without the incredible stress that comes with breaking an engine in when it's overly rich & cold. After cycling the engine in this mannerfor about 20-25 total minutes, it'll be ready for the track and race tuning. I realize this method goes against the old-school "idle on the box" routine, but you'll be amazed once you've completed this break-in routine, your OS will still have amazing pinch w/out sticking at the top AND your OS's compression will last far longer than it will with the "old school" method.
You say you run the engine at "factory settings" for the first FIVE tanks? That alone causes lots of stress, as the factory OS settings are very rich on every OS I've ever owned or tuned. The piston & sleeve haven't expanded to operating temps, and every time the engine turns over, the piston slams into the pinch zone at TDC. The not-so-surprising result can be a cracked con-rod at the crank pin--that's where the majority of the stresses occur as the engine turns over. I've only heard of about 6-8 OS engines breaking con-rods, and they're ALWAYS during the first gallon...and almost every time it's because the guys have performed the break-in procedure you described. Doesn't seem like a mystery as to why it's happening. Drawing out the break-in routine really stresses the engine & actually wears away compression along the way. This method I've outlined will feel weird at every step, but after you try it once, you'll notice a big difference in your engine's performance & lifespan.
Hope this helps; give this break-in method a shot--you have nothing to gain except longer life & more power
If you are still idling at least a tank through during break-in, you're using the old-school accepted method (still works well for some!) but it's not the method that the top engine guys (Ron Paris, Dennis Richey, Rody Roem, Michael Salven are just a few I've spoken personally with about this) recommend anymore.
From the very 1st time you start your engine, plop the car on the ground & begin running it in a parking lot in 2-3 minute intervals, tuned only *slightly rich* getting the temps up in the 200F range on a normal day. Every 2-3 minutes, shut the engine down & let it cool completely with the piston at BDC, and then fire it back up; continue this cycle until you've run 15 min or so, and then bump up to 3-4 minute intervals. Vary the RPM and don't be afraid to get the temps in the 200's. What you want is heat cycling of the components without the incredible stress that comes with breaking an engine in when it's overly rich & cold. After cycling the engine in this mannerfor about 20-25 total minutes, it'll be ready for the track and race tuning. I realize this method goes against the old-school "idle on the box" routine, but you'll be amazed once you've completed this break-in routine, your OS will still have amazing pinch w/out sticking at the top AND your OS's compression will last far longer than it will with the "old school" method.
You say you run the engine at "factory settings" for the first FIVE tanks? That alone causes lots of stress, as the factory OS settings are very rich on every OS I've ever owned or tuned. The piston & sleeve haven't expanded to operating temps, and every time the engine turns over, the piston slams into the pinch zone at TDC. The not-so-surprising result can be a cracked con-rod at the crank pin--that's where the majority of the stresses occur as the engine turns over. I've only heard of about 6-8 OS engines breaking con-rods, and they're ALWAYS during the first gallon...and almost every time it's because the guys have performed the break-in procedure you described. Doesn't seem like a mystery as to why it's happening. Drawing out the break-in routine really stresses the engine & actually wears away compression along the way. This method I've outlined will feel weird at every step, but after you try it once, you'll notice a big difference in your engine's performance & lifespan.
Hope this helps; give this break-in method a shot--you have nothing to gain except longer life & more power
05-08-2006, 07:51 PM
#3
Josh Cyrul's method: http://www.cefx.net/tips/nitro/break-in/index.php
He also answers questions on break-in if you don't understand his method.
He also answers questions on break-in if you don't understand his method.
05-08-2006, 11:22 PM
#4
Tech Regular
Thread Starter
Thanks for the info i will try the STEPHEN BESS method.
05-09-2006, 06:39 PM
#5
bodido nailed it. thermal cycling the metals is the way to properly break in a motor. 
05-10-2006, 05:10 AM
#7
tried the tamiya manual by breaking it in using rich fuel - finished 5 tanks and the piston is still very tight.... going to try leaning it up and get it running.
thanks for the tips
thanks for the tips
05-10-2006, 05:55 AM
#8
Engine method
I discussed this with a college professor that supervises a formula type race team.
He said break-in only has a few key elements.
1. Do not idle the engine. Get it rolling soon. Just putt around and don't load the motor.
NOTE - You need to have the idle set correctly. Most engines come way rich. Use the top needle to get to temp. Keep in mind the piston and the sleeve are different materials and will not expand correctly until they have reached a certain temperature.
Get to 200 degrees as fast as possible and keep it there. Run the car for 3 or so tanks to allow the parts to lap in. Keep the motor running for this entire process using very short blips of the throttle. Don't turn the motor off and don't get on the gas hard.
2. After a cool down (10 minutes after the motor temps less than 90 degrees) run the car using 1/2 second throttle inputs. The motor should not be comming up on the pipe. Keep the motor between 200 and 230 degrees using the top needle only. Turn the motor off after each tank and let it cool using the rule from above. Repeat this until you have run at least 3 tanks this way.
3. Change the motor input to 3/4 second throttle inputs following the same guidelines for step 2. Make sure the car is smoking properly and only use the high needle.
After step three is completed you should have at least nine tanks on your motor and you are ready for an idle setup and tune. You should be ready to get the motor up on the pipe now.
Hope this helps,
TEX
He said break-in only has a few key elements.
1. Do not idle the engine. Get it rolling soon. Just putt around and don't load the motor.
NOTE - You need to have the idle set correctly. Most engines come way rich. Use the top needle to get to temp. Keep in mind the piston and the sleeve are different materials and will not expand correctly until they have reached a certain temperature.
Get to 200 degrees as fast as possible and keep it there. Run the car for 3 or so tanks to allow the parts to lap in. Keep the motor running for this entire process using very short blips of the throttle. Don't turn the motor off and don't get on the gas hard.
2. After a cool down (10 minutes after the motor temps less than 90 degrees) run the car using 1/2 second throttle inputs. The motor should not be comming up on the pipe. Keep the motor between 200 and 230 degrees using the top needle only. Turn the motor off after each tank and let it cool using the rule from above. Repeat this until you have run at least 3 tanks this way.
3. Change the motor input to 3/4 second throttle inputs following the same guidelines for step 2. Make sure the car is smoking properly and only use the high needle.
After step three is completed you should have at least nine tanks on your motor and you are ready for an idle setup and tune. You should be ready to get the motor up on the pipe now.
Hope this helps,
TEX
05-10-2006, 06:16 AM
#9
A couple of things.
1. Every time you turn the motor off or it quits, make sure you move the motor away from top dead center. When the piston and sleeve shrink during cooling you do not want them to be strained by being in the top pinch zone.
2. Thermal cycling is not effective until the parts are lapped in and have proper fit with each other. This is why we run the motor constantly during the first step mentioned. Starting the motor before this process is complete makes the parts wear on each other while they are not at their correct size. This why temp is important in this first step. If the car gets above 230 just richen the top needle some and continue running. Having the motor shut off and having to restart it will hurt it much more than the motor being 50 degrees hot.
3. Thermal cycling lets fitted parts form a better friction surface.
TEX
2. Thermal cycling is not effective until the parts are lapped in and have proper fit with each other. This is why we run the motor constantly during the first step mentioned. Starting the motor before this process is complete makes the parts wear on each other while they are not at their correct size. This why temp is important in this first step. If the car gets above 230 just richen the top needle some and continue running. Having the motor shut off and having to restart it will hurt it much more than the motor being 50 degrees hot.
3. Thermal cycling lets fitted parts form a better friction surface.
TEX
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