Engine break in procedure

[SayMikey]

Recently I started running off road electrics. While trying to learn as much as I can I was watching the car guys warm there motors before a heat. Seems the hot dogs all use a heat gun to warm to around 150 degrees before firing, This saves pinch and stress on con rod,it also make s the engine fire right up. Then I read an article written, have a look and think about it and how it could help break in a new engine. "the break in bible"

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 XX'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 XX settings are very rich on every XX 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 XX 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

not written by me , STEVEN BESS wrote the article

 

[dave roach]

Mikey

I heat cycle my engines on the test stand.getting the engine up to 240 deg. then let it cool down and do the same thing over and over for about 2 tanks.Then the engine is race ready.

The rod does not break on the up stroke.All the damage happens on the down stroke.

Dave

 

[Joe Warren]

What was your Best Performing Engine & How did it get broke it????? I actually think that A Great engine starts with a Great Crankcase & Crank alignment. Most Great engines will see many Piston/sleeves assemblies if you keep it for a long time. IF You loose the case?? Chances are you have lost your Great engine....... it will become average... Now that is just my experience.... B)

 

[Joe Warren]

Recently I started running off road electrics. While trying to learn as much as I can I was watching the car guys warm there motors before a heat. Seems the hot dogs all use a heat gun to warm to around 150 degrees before firing, This saves pinch and stress on con rod,it also make s the engine fire right up. Then I read an article written, have a look and think about it and how it could help break in a new engine. "the break in bible"

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 XX'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 XX settings are very rich on every XX 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 XX 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

not written by me , STEVEN BESS wrote the article

B)

 

[Tom Foley]

Interesting . All the new engines I've ever had I've used the "OLD " method and been rewarded with years of good power and service ..lots of ways to cut a cake . I usually run them on the table a few times before the water just to get the "gross " needle setting to where the engine will take throttle but not completely clear out and over rev . Then it's ready for a little water "load " test . seems to work OK . That is an interesting method though , may try it .

 

[anthony_marquart]

I definitely agree with this. Putting a heat gun to a new motor makes it 10x easier to start... runing the p/l below operating temp will cause wear!!!

 

[Joe Warren]

I like the heat gun idea. Many of the High dollar alum engine that speed across the dirt trax of american have electric block heaters. They dont dare push off till the water temp is @ 180-190. Considering that many of them are machined with the tolerances @ operating temp. 180-210 Donavan Racing Blocks are line honed @ 185 degrees. they use oil to heat the block prior to honing.... The #1 importance or Our little engines is Buy a torque wrench & learn to use it properly. A properly torqued race engine will always out perform a engine that is not... & Never strike the crank or brgs for any reason, if so do you will greatly shorten their life.

 

[Jerry Wyss]

I developed a method during the spring of 2009 for breaking-in some 21 o/b powerheads that has been very successful. The first two o/b's were Thunder Tigers that were specifically prepared for IMPBA Sport 20 Tunnel class.

The o/b's were mounted on one of my tunnels and fitted complete w/radio ready to run. The radio was not used until the 7th tank, the carb was simply rotated by hand for 1/2 throttle opening. The engine was started overly rich and I pinched the fuel line to regulate start and running thru six 8oz tanks.

The method allowed the use of both hands, one to pinch and regulate fuel and the other to hold a heat gun. Each tank the rpms and heat were elevated. I imagine to some people the rpms were way too high near the last few tanks. But really didn't rise much higher than the way some people take them to the water during normal racing. The whole o/b was allowed to get quite hot, the lower unit became a very useful heat sink.

The idea was to get the entire engine to possible future running temps and to be able to regulate more than enough lube for the engine at any time. The engines, heat gunned at the plug was allowed to go over 270* for brief periods of time with a fair amount of rpms. The higher rpms actually revealed a slight vibration in the first engine. That was later cured in the second engine by cutting some of the piston skirt that patially blocked the the transfer and boost ports. The second engine was much smoother in the higher rpm range tested. The former engine piston skirt was cut also and broke-in again.

The 7th tank had the transmitter turned on and a reasonable needle setting was found for water testing. At least 5 tanks were run with the boat on the water until the engine found its mark. All runs used the cool with fuel method and engine performance was quite amazing for a near stock TT o/b.

These engines run a healthy compressed stroke and fairly high compression ratio and are prepared for 30 to 35% nitro. That compression has held for one season and is still good enough for another and possibly more after that.

This method has satisfied all the requirements for a good break-in, except for prop load. From what I have seen, prop load wasn't a necessary requirement after all. The key plus here is if the engine ever encounters a lean run condition(which they have), its actually been swelled near that in break-in so the damage to parts is less evident.

dub

 

[Terry Keeley]

My buddy Olly used a heat gun to break in a tight NR, made a world of difference.

 

[Andy Greene]

I have used the heat cycle method on the bench for my last 2 motors , they were not brand new out of the box- but did have new liner and piston. It sure beats putting around the pond for 2 gal. and I dont seem to have any performance issues. Just my .02

Andy