Heat Cycle Breakin Method

[The Slacker]

I just got an OS and might break it in tomorrow if I get my parts. They say slightly rich, will the factory settings work all right?

 

[jetmechG550]

Out of the box it will prolly be on the rich side (in most cases). Slightly rich would be barely running or able to stay running for too long.

 

[Brushlessboy]

Smaxxin. Would it be acceptable to run it on a block without a fan, and run the revs up through the range, while monitoring the temps. I have done this with my first tank on my Savage X. Only turning on the fan when temps got to 200.
Is this an acceptable variation of heat cycling, or is it a waste of time?

 

[space coast racing]

Yes indeed heat cycling works great !! I have used it on 10 engines or so and no prb, or engines puffing before there time lol !! Pinch seems to last much longer too

 

[flandersander]

So we're clear, i have only broken in 1 engine. I did what the manuel told me and it works fine. have had it for a couple years and only had to sleeve it once. And it sucked in some water. so don't attack me for what I said as I was only stating my opinion which is what this forum is for.

 

[Truggster08]

Take a look at this breakin procedure. Just another way of lookin at it. Sounds kinda crazy to me.
http://www.cefx.net/tips/nitro/break-in/index.php

 

[hrdcoreglf1]

Heat Cycle Method

ABC break-in in the car

Set the main needle according to the manufacturer's specifications (e.g., 2 to 3 turns counterclockwise from closed). Open the idle needle several turns so the engine shuts off when abruptly throttled back.
-Start the engine
-Advance the throttle to 1/2. Listen for 4-cycling. Lean the mixture to a rich two cycle operation.
-Run the car in a 100 foot diameter circle or figure 8. Keep the throttle at 1/2 and listen for 4-cycling. Don't let this happen! If it does, immediately lean the main fuel needle a little at a time until the engine produces a clean, steady 2-cycling sound. Run your car in a cicle/ figure 8 for about 1 minute. When the minute is up immediatly check the head temp.
Keep a log of run time, head temp, estimated rpm and your perfomance comments.
The goal is to keep the head temp. at above 200 degrees F. and less than approximately 230 degrees F. If the head temp. is less than 200 degrees F. lean the high speed needle slightly, and try again after the engine has completely cooled. When the engine stops, using the fly wheel turn the piston to BDC.
-Perform the 1 minute run at least three times while you adjust the head temp. by "tweaking" the needle valve as needed.
-Now run the car around for 2 minutes at least twice. Remember: 1/2 throttle and no four cycling. Same game : check head temp., allow it to cool, record data.
-Don't be tempted to open the throttle wide! The mixture settings will probably be all wrong for wide open throttle(WOT)(. There is plenty of time for that later.
-The rest of the 1/2 throttle break-in runs will be 3 minutes long. When they tottle 35 minutes(minimum), you have successfully heat-cycled your engine and break-in is properly complete. If you like you can run it another 10 minutes or so it won't hurt.
-Tune the engine for WOT and idle operation.
To read " Super Engine Tining" by Steve Pond go to ( rcnitro.com/artcles/index.asp )

Heat cycling for stress relief
Stress relief is accomplished by repeatedly heating and cooling the engine-short engine runs followed by complete cooling repeated many times. ABC engine break-in involves such heat cycles, betit is not the same proceedure as is used for non ABC engines.

ABC break-in the inside story
Abc engines require a shorter break-in (heat cycling) than engines of the past- less than 45 min. for most. To attain and maintain maximum power levels, however, requires adherence to an entirely new set of break-in rules.
The primary objective of ABC break-in is to maintain the delicate top of the piston pinch zone while allowing the internal engine components to heat cycle with some minor smoothing and allignment (crankpin, wristpin, rod journals, etc.).

Here is how this is achieved:
FUEL- Use the same fuel for break-in as you will for normal operation. If you break-in your engine with low nitromethane fuel, e.g., 5% and then jump to 20% for actual running, the piston / cylinder fit will be too loose. Five % nitro doesn't generate as high a combustion temp., so the cylinder won't expand as much, and the pinch zone will wear more than if the cylinder had pulled away farther, as it would with the hotter burning, higher nitro fuel.

2- vs. 4-cycling operation
If you run a 2-stroke engine then you have heard of 4-cycling. When a two stroke engine is operated very fuel-rich or at somewhere below 1/2 throttle, it begins to fire on alternate crankshaft revolution. As the mixture is richened at wide open throttle, the ehaust sounds like this as it breaks from 2-cycling to 4-cycling: " RRREEEAAAHHHHHHH."
As the throttle is reduced to about 1/2, the exaust sounds like this, as it breaks from 2-cycling to 4-cycling: "RRRRREEEEETAT-TAT-TAT-TAT."
With both examples comes a simotanios loss of rpm with the change in exuast sound. This is 4-cycling. Learn to avoidit. Because the ABC-type engines were originally designed as WOT racing engines, their pistons and cylinders operated happily. Today, ABC engines are also expected to idle and throttle reliably. Unfortunatly this allows them to cool excessively, especially below 1/2 throttle, where poor cylinder scavenging (clearing) causes them to 4-cycle and wear away the critical pinch zone as the piston sleeve cools and tightens around the piston
Throttling is a necessary phase of running nitro engines in cars, so you can't simply eliminate it from your routine, but do not allow the engine to 4-cycle during break-in. Afterward, when engine components have been stess-relieved and bedded in through heat-cycling, the wearing effect of 4-cycling will be minimized.

Tight ABC piston/cylinder assemblies
Some new Abc-type engines are so tight at TDC that for the first few times the engine is cranked over and run, the possibility exist of damaging the connecting rod, crankpin, and piston. To avoid this, preheat the cylinder and the head with a heat gun or a hair dryer. This preheating expands the piston sleeve, and that minimizes the potential for stress on all the engine components during initial startup.

 

[cooldude]

ok I'm ready to break my rb .23 turbo engine..this will be my second time breaking in a engine..the first engine was a 3.3 traxxas..

my question is whats the best method for break-in I'm a bit confuse theres many ways..

1.heat cycle

2.traxxas method

3.others one can't desicribe it thoe.

dose doing the heat cycle on a turbo engine a good idea? is that mostly for a non turbo engine method?

traxxas will do fine?

thanks

 

[seanmcgrath48]

Heat Cycle Break-in Method

I've been read'n the Heat Cycle Break-in Method,
I under stand what must be done, even thoe I'd never heard of it before,there's nobody over here in WestCork in IRELAND that's into R/C nitro's,
I was still do'n it Old School:\.
What I want to know is,as I've started to break-in my Sirio.18tx (after engine rebuild)Sirio sent me a FREE piston kit,did my usuall 2 tanks on idle,Had to stop at that because weather turn'd bad.
then came across this method on RCNT, can I change know to the Heat Cycle Method on my engine,even thoe I've done the idle bit, with out doing any damage to my engine. . . .
Regards Sean . WestCork in IRELAND

 

[solly69]

How should i break in the Engine in my HSP Warhead?

I know hardly anything about this because i have never had a RC car before and never watched a friend do it?

Any advice is good advice for me.
I have done a Automotive Course at tafe so i have a rough about 4stroke engines but nothing on 2strokes

 

[Scrogg]

In your case follow the manual to the "T". On your next engine then try a heat cycle. Once you gain the experience of what they sound like and run like when they are lean or rich, then do a heat cycle.
Just let the engine cool for 15 minutes between runs.
Preheat the engine with a hair dryer or heat gun if you have one. Do this for the first 5 tanks, 2 strokes hate being cold.

 

[rccks]

breaking in my OS .28XZ on saturday. I know people said that it works great, is it? Just wanted to make sure, i don't want to start off the season with a broken engine..

 

[New2Nitros]

Don't take this wrong, but that was hard to read and I'm not sure exactly what your two cents is?

A few well placed commas, alot of editing, some periods and I think I might see what he's "driving" toward. I however hope to learn from you guys who know what to do so I avoid ruining engines for no reason

 

[ReeV0]

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 manner for 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.



BDC means Bottom Dead Center. This is when you roll the crank until the piston is at the very bottom of the crank case. Before you install your new engine look at the piston through the exhaust and when the piston is at the bottom put a mark on the flywheel. This will make it easy to set the piston to BDC.

Is this method still valid? How does it compare to the Adam Drake method which has been recommended to me? (I'm new to nitro)

 

[CertifiedMike]

Is this method still valid? How does it compare to the Adam Drake method which has been recommended to me? (I'm new to nitro)

Hi! I'm old to nitro. I used this method more or less a few (about 10) years back and a few further than that too.

If you are working on an old traxxas 3.3 motor, this method should still work as it had then. There may be better methods now too.
However, newer motors are not built the same way (much tighter pinch) and must be broken in and subsequently started with plenty of heat before the motor is ever turned over.
Even for older motors, heating is smart.

I don't own these newer motors and so am repeating more than knowing. I will be back-pedaling a lot before I can catch up with 'new' nitro.

@Littlemotor is def your guy to ask about this stuff.
Hes got SO much knowledge!!! I recommend you go thru his posts, builds etc. and absorb as much as you can.
Even if its not for YOUR truck or motor, you can apply most of it to your gear.

There are lots of other folks here who can guide you as well so search and read a LOT!

Before we were taken over by lipo's in the silent nitro wars, this site was called RCN(ITRO)TALK.COM!!!
There are still a few who remember.

Read up!

Forget NOTHING!!!


We'll be testing you later!!!

 

[ReeV0]

Hi! I'm old to nitro. I used this method more or less a few (about 10) years back and a few further than that too.

If you are working on an old traxxas 3.3 motor, this method should still work as it had then. There may be better methods now too.
However, newer motors are not built the same way (much tighter pinch) and must be broken in and subsequently started with plenty of heat before the motor is ever turned over.
Even for older motors, heating is smart.

I don't own these newer motors and so am repeating more than knowing. I will be back-pedaling a lot before I can catch up with 'new' nitro.

@Littlemotor is def your guy to ask about this stuff.
Hes got SO much knowledge!!! I recommend you go thru his posts, builds etc. and absorb as much as you can.
Even if its not for YOUR truck or motor, you can apply most of it to your gear.

There are lots of other folks here who can guide you as well so search and read a LOT!

Before we were taken over by lipo's in the silent nitro wars, this site was called RCN(ITRO)TALK.COM!!!
There are still a few who remember.

Read up!

Forget NOTHING!!!


We'll be testing you later!!!

Thanks for the reply. It is a TRX 3.3 motor, though it is brand new. Well, not any more as I've run 3 tanks through it using the above Adam Drake idling method. I did preheat it using a SkyRC engine heater each time, though it only managed to get it up to 50c rather than the required 80c. Still, it started up no problem every time.

I was of the impression that there has been little improvement in regards to nitro engine since around 2010, when lipo's started hitting the scene? Are there many RTR nitro motors out now that are much better than the 3.3? (excluding your $500+ motors)

 

[CertifiedMike]

The 3.3 is a durable little motor. It produces decent power and is ok.
There are plenty of motors out there that will outperform it however.
Like most things in life, you get what you pay for.
You are new to nitro so I think its a fine motor to learn with.

Always run your tank out of fuel. Old fuel causes problems. Empty tanks avoid them.

Use after run oil. Its WAY cheaper than buying a new motor and gets you in practice for when you do own $500+ motors.

Store your motor with the piston at BOTTOM of the stroke for maximum motor life.

 

[CertifiedMike]

@Chubaka has built a bunch of 3.3 Traxxas. I see he's lurking...

If you ask nicely and brimg him Wookie Snax, he might be able to give you some pointers too.

 

[Chubaka]

@Chubaka has built a bunch of 3.3 Traxxas. I see he's lurking...

If you ask nicely and brimg him Wookie Snax, he might be able to give you some pointers too.

You covered it all. I only have one 3.3 and it was broke in tge traxxas way in 2014. Gonna buy a few more nitro motors in the foreseeable futures.

 

[CertifiedMike]

You covered it all. I only have one 3.3 and it was broke in tge traxxas way in 2014. Gonna buy a few more nitro motors in the foreseeable futures.

You have 2.5's right?

2 X 2.5 = 3.3

I don't maths good.