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engine break-in theory

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Old 01-18-2004, 05:16 PM
  #1  
fumblenutz2g
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Default engine break-in theory

sup
i was wondering if i could break in a motor with out actually driving the truck
i was going to hold it in the air and follow the break in rules
can it be done
if it can be done are there any other steps that need to be done
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Old 01-18-2004, 05:18 PM
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yamahamoto22
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Default RE: engine break-in theory

read your book...it says not to rev the motor while holding if off of the ground
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Old 01-18-2004, 05:23 PM
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fumblenutz2g
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Default RE: engine break-in theory

i kno it says that but what effect wuld it have oon the motor for doing it any way
the tires and everything still move at the same
they dont tell u why not to do it
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Old 01-18-2004, 05:26 PM
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Default RE: engine break-in theory

Because the drivetrain, tires, ground, and weight of the truck offer resistance against the engine, which is crutial for proper break-in.
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Old 01-18-2004, 05:33 PM
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fumblenutz2g
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Default RE: engine break-in theory

so if i could could leave it on the ground and put the tires on sum rollers
wuld that keep the weight and everything the same
i jus wanna do it so it stays in one spot
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Old 01-18-2004, 06:15 PM
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fhm101
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Default RE: engine break-in theory

Since it's your truck and it sounds like you are determined to do it in spite of what traxxas and the folks that posted to this thread think, please go ahead and do so then let us know how it works.
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Old 01-18-2004, 07:02 PM
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Default RE: engine break-in theory

I don't understand why you won't drive it around while breaking it in. You are going to drive it around afterward right? You could break it in on rollers, but that would be a lot of work just for breaking it in. But like fhm said, its your truck do what you want.
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Old 01-18-2004, 08:05 PM
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Default RE: engine break-in theory

ok, just mount it in your chassis and take the wheels off, then it will go NO WHERE.
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Old 01-18-2004, 08:09 PM
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mecky33
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Default RE: engine break-in theory

If he does that, there is still no rolling resistance. and that is part of whats required for the breakin.
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Old 01-18-2004, 08:22 PM
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Default RE: engine break-in theory

the only way to do what you want is by putting a propeller on the crank and breaking it in like an airplane engine.
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Old 01-18-2004, 08:31 PM
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Default RE: engine break-in theory

I dont know what the issue is here.. but

Thats how they break in a lot of airplane engines.. on a stand. BUT
The resistance is the prop blade.

An engine will run VERY different under load. Also, when the engine isnt moving, its not getting any cooling.


One thing I dont understand however is.. Why does LOAD on an engine prevent it from breaking a con rod?
How does that matter?!!
Nitroaddict? i8tweety?

Ram
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Old 01-18-2004, 09:06 PM
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Default RE: engine break-in theory

The reason why the con rod would break is because the engine is over-reving. When the engine spins faster then it is designed to, it makes a lot of heat and affects the metal on the con rod which makes it weak so it breaks(???) I really don't know if thats how it causes it to break but I'm just basing it on theory. Do you agree?
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Old 01-18-2004, 09:36 PM
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Default RE: engine break-in theory

I agree, without a load on the engine, it will rev higher. Higher than the conrod was designed to, and put too much un-needed stress on it. As far as airplane engines, they are airplane engines, not car engines. They are designed to withstand the stress that they are designed to create, and should be broke-in accordingly.
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Old 01-18-2004, 09:55 PM
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Default RE: engine break-in theory

Many pros who own MT's actualy use the plane brake-in meathod. Supposedly it creates less friction on the engine which in return decreases heat. If you use this meathod, then you need to preheat the engine head with a blow drier for a while to get it up to somewhat normal running temperatures. When you do this, You do not need to let the engine cool beacuse not only is it causeing less fritcion, but it cools the engine with the propeller. You woulld probably think that yes, heat cycleing is very important but the thing is, when you use this meathod it uses *aprox. 80 degrees lower than average so when you very the throttle it actuly cools and heats its self.

Even when using this meathod, I still recomend heat cyceling.
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Old 01-18-2004, 09:58 PM
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Default RE: engine break-in theory

fumblenuts, read [link=http://www.rcuniverse.com/forum/Lesson_learned_the_hard_way%25/m_1443300/tm.htm]this[/link]
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Old 01-18-2004, 10:21 PM
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Default RE: engine break-in theory

Serpent Racing makes an engine break-in stand for .12, .15 and .21's. Its a fairly simple design with mini prop acting at the weight and cooling method. http://www.mytsn.com/products/desc.asp?prid=150
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Old 01-18-2004, 11:46 PM
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Default RE: engine break-in theory

well if you let an engine idle through a tank of fuel it barely has any resistance. All it has is the weight of the flywheel and clutch shoes. Nothing is actually engaging. So what all you guys are saying is that people who let it idle through 1-2 tanks are doing it wrong? I was just wondering since ive seen people say they let it idle for 1-2 tanks then half speed the next 2-3. Ive never done it that way because thats what i thought.
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Old 01-19-2004, 01:39 AM
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Default RE: engine break-in theory

i was wondering about this because its snowing and really cold outside
my next door neighbor jus got his nitro rustler today an wanted to break it in
he want to hurry up and do this but with out gettin the car wet(rite now)
we were searching for parking garages put cant find any in a 10 mile radius from where were located so we came up with let hold the truck up in the air and try doing it like that
i told him to hold off on it cuz we didnt kno if it would actually work or not
what we came up with rite now is to use this rc dyno we got off the internet from thir guy who makes them he says that they cum with the restistence in the rollers
jus set ur car on top of it crank it up and let it loose
so i guess well try that and see if it works unless sum one can give me a better idea
hes only doing this so he can run in the snow with me or shuld i say try to run with me
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Old 01-19-2004, 08:57 AM
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Default RE: engine break-in theory

I personally break in my engines per the instructions of Rody Roem, Owner of RB Concepts Engines. I break them in at first on a stand, full throttle, with a prop, then move to the ground, also running full throttle using a heat cycle method. Here are some quotes from Mr. Roem himself:

Also there are some things I personally do not do is for example start the engine with an electric starter and this you have to do with a Hudy bench if you do not take off the protection.
I of course cannot tell you to take of the protection for safety reasons.

Anyway, if you still want to do it in this way, I think in this way you cannot do a lot of things wrong.
So before you start to run in an engine I suggest you cover the cooling-head with something so the engine heats-up properly(without the cover the engine will stay too cold).
Then start the engine and let it run rich at full throttle for 2-tanks at a temperature of about 80°C.
Then 2 more tanks at 90°C.
Then 1 more tank at 100°C.

After this your engine is almost run-in, however you need to finish the rest of the running-in in the car for about 2 more tanks and you are then ready to go.

Hope this helps you further
ALL the tanks at 80,90,100c are ran at full throttle? Do you just let cool between each tank as well or more often? Is the break-in RPM range somewhere around 50-60% of race tune RPM's?

Thanks
-----------
Yes, we do this at full trottle and yes, it might be a good idea to let the engine cooll-down, between the sessions. - Rody
With the engine full-throttle, you are sure that the idle needle is not in front of the spraybar and so you are running the engine really on the setting of the main-needle and so are also sure the engine will run rich.
Also more fuel/air will go through the engine with full throttle so a better lubrification.

The only way to make your engine last is to treat it well and to protect it from dust coming into the engine with a proper carburetor setting and a regular maintenance.

When we pre-run the engines on our bench the general temperature reached is 80°C and on the last run I make it peak till 100°C.


We still supply pre-run engines and this is done in the same way we do this on our team-engines which are working perfectly. If this was not a good way to do this then we simply would not do this...
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Old 01-19-2004, 09:15 AM
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Default RE: engine break-in theory

Here is something from OS Engines, it basically says that the recommended procedure that comes in your instruction manual is the wrong thing to do to your engine.

http://www.osengines.com/faq/product-faq.html#q590


Here is a quote:

"The break in process of model engines, especially R/C car engines has been affected by a wide variety of myths and misconceptions. The main one is that the engine must be run at idle for several tanks' worth of fuel before the model is run. There is nothing farther from the truth! In fact, running the engine at idle for several tanks' worth of fuel will not only insure that your engine won't break in properly, but it could also reduce its overall life!"
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Old 01-19-2004, 09:31 AM
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Default RE: engine break-in theory

We started using a new procedure a little while ago. It has been widely and is said to give great results. Personally I couldn't tell you how it works for sure because I only have 3/4 gallon through the engine, here it is anyway.


Here's the break-in method I posted several months ago. It's the basic "heat cycle" method that was popularized by Ron Paris, and then altered and refined in RC Nitro & Car Action magazine by Dave Gierke, Steve Pond and myself in a series of engine articles we published. It's useful for any ABC-constructed engine that employs a lapped piston/sleeve design. Hope it helps.
------------------------------------------------------------
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 engine will still have amazing pinch w/out sticking at the top AND your engine compression will last far longer than it will with
your 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.
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Old 01-19-2004, 05:49 PM
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Default RE: engine break-in theory

THANX YALL
IF ANY ONE HAS ANY MORE INFO UR WELCUM TO SHARE
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