Engine Break-In at WOT?

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THE JUDGE

THE JUDGE

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I've been doing a lot (maybe too much) of reading regarding 2-stroke ABC engine break-in, and I found this method here:

http://www.rcuniverse.com/forum/fb.asp?m=6811864

To be perfectly honest, this method makes far more sense than any other way I have heard about. What I'm wondering if any of you have heard of or used this method, and anyone's opinion on such.

TIA
 
Makes sense to me. My only concern would be the connecting rod and having it fail from tight pinch and higher RPMS.
I understand the heat necessity though and I did a friends break in similarly.
Didn't idle though tanks just plopped her on the ground right away after heating block up with a heat gun. Ran one tank that way and started tuning and so far so good on it-no problems.
But on my Axial I did it the way LHS suggested and how Axial suggested just so if I had problems I could honestly say I did it how I was told. So far so good on this one too.
 
Interesting, and it does make sense. I think Dave hit the nail on the head, the connecting rod would be put under excess amounts of stress due to the extreme pinch from the factory. Maybe I will dust off the old Supertigre .27, grab a new P&S and try this out.
 
Good point about the con-rod guys, but remember, if you do this procedure running really rich, you should never get anywhere near max RPM's anyway, and if you pre-heat the block well, the pinch won't be as much of an issue I would think.
 
that is a interesting method, but risky i would think but who knows as i've never tried it so it may work well
 
Jester said:
My .2 cents is do what manf says
Click to expand...

I used to believe that...until I realized that, just like 1:1 cars, the manuf. will reccomend whatever procedure is the hardest for a noob to screw up, not neccessarily what will make the engine last the longest. It's hard to mess up idling through a bunch of tanks, even though that causes more wear than other methods...Trust me, HPI etc. would way rather have less warranty claims than have motors that last a while longer...the almighty dollar at work.

(Of course, this is only my 2 cents too)
 
I'd say that's a no-no. 3 things are happening during break in.

1 - Wear-In. This is the MOST critical time of any engines life, whether it be a 2 stroke, 4 stroke, 4 stroke diesel, or whatever internal combustion engine it is.

During this period, the parts must wear in together. Machining is an art, along with plating, honing.. and every other type of surfacing, specially with an engine. HOWEVER! You must remember, even with the softest of tools, there are still going to be burs compared to what your cylinder will look like in half a gallon after it's first started.

If you compare a brand new piston/cylinder with a pair with a single gallon on it, you'll notice a giant difference. This is where you get that "make it or break it" time in your engine. That "grinding" away on the cylinder is what you WANT during break-in.

2 - Component Stress Test. If it's gonna fail from a manufacturer defect, you'll know within a few tanks usually. 99% of major motor failures that occur in the first couple of tanks are due to manufacturer problems, or operator error (such as snapped conrods due to hydrolocking)

3 - Initial startup. During the first 15 seconds that your motor will run, it will be spitting more metal shavings than if it was ran so lean that she his 400+ degrees. That's because of the issue in step 1, where nothings perfectly smooth; even if it appears to be so.


A really big thing you'll notice with new engines, whether you idle the tanks, or run them hard at first; the temp is always high in the first few tanks of runtime. This is due to the excessive wear on the engine that is taking place. If you run the breakin richness on the motor 3-4 gallons later, your temps will be about 30-50 degrees cooler, just because of the lack of wear.

During this time, it's CRITICAL, that you don't stress the motor more than you have to. The idle method is very good for a first tank, but not much more than that. Idling with the wheels off the ground is good, but without anything attached to the motor is best. No clutch bell either; that's the best for the engine, as there is no drag on the engine while it goes through it's initial "cleaning" process; if you want to call it that.

Theoretically, you could idle the tank for 5-10 minutes then walk away with bashing insanity with no adverse effects. However, you could have the same exact motor, idle for five minutes then go try to bash and end up with a nice set of guages on the cylinder wall from a metal shaving.

This is why it's important to keep it right, and SLOW. This way, the motor can properly mesh itself inside, and stay cool enough to protect the components. Making sure you have a rich breaking, with low stress is key.

If he would actually look into it, he'd realize what exactly goes on during break-in. It's not the temperature that matters as much as it does with imperfections that may lie on the cylinder wall. One WOT run can make or break the engine at any time. Wouldn't you rather have a nice firmly seated piston inside a cylinder that perfectly matches up with it? Or would you rather have a rigid surface that you can't see with your eyes, or even feel with your finger slapping your brand new piston around?

Sorry for the rant, I just hate it when people who don't explore a subject totally rant off on something that is important to someone. Personally, I'm not a part of that forum, but if I was, I'd reply with this same post.
 
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yea aod, plus reps for you, i was going to say the same thing in a cliffnotes form..

this procedure is also different from a 1:1 car just due to the size of the engine. 1 grain of sand or one scratch of metal will have different, although still not good, effects on a 4.6 then a 4600cc engine..
 
Major props for the well-worded post AoD, but I'm still gonna repectfully disagree with you...the reason why this procedure makes sense to me is because engines are a subject I have explored for well over 20 years (thus the above accusation doesn't insult me one bit) and I'll try to explain further:

1-Wear-In....This is a bit of a misnomer, really. The real purpose of "breaking-in" a 2-stroke like these is to heat-cycle the engine as a whole for the purposes of STRESS RELIEF and to promote EVEN EXPANSION, not to wear the pinch down slowly. Sure, there will be some wear on the piston/sleeve no matter what, but there's no reason to create any more than to where the engine isn't overheating from the friction of an intentionally tight fit. It should be more of a "burnishing" operation than a grind job, and that applies to all the moving parts...Just like polishing a crank journal rather than grinding it down to reduce friction, it's something that's better not to overdo.

2-Component Stress Test...I totally, totally disagree on this one. If it's a manufacturing flaw, the motor's compromised regardless of what the end user does. And if you hydro-lock it? Nobody to blame but the person who is running it way too rich to begin with. Part-throttle running won't prevent that!

3-Initial Startup...The idea of metal shavings during the first 15 seconds of running is really a moot point, since you have to warm the motor up by running it, no matter how you're trying to break it in. Not only that, how can anyone say that metal particles floating around at, say 3000 rpms is any better than at 20,000 rpms? In fact, from what I said above and below, running a motor below proper operating temps will likely cause MORE shavings, because the sleeve hasn't expanded to where it should be. It's the extra oil from running rich helping to protect the parts that matters, not low loads and slow engine speeds...that applies more to ringed-piston engines.

Beyond this, please pay attention to the part of that procedure where you run the motor up to operating temp for a couple of minutes, then shut it off and let it cool. I never saw where it was recommended to just beat the snot out of the motor until the tank runs dry, that would of course be counter-productive. Heat cycling is still very much the key here.

A big mistake people make is when they equate ABC engine break-in with ringed-piston engine break-in. With rings, the point is to get them to seal, which they typically don't do at first (although even this has changed dramatically over the years). ABC engines, on the other hand, have the BEST cylinder sealing when they're brand new, and we unfortunately have to trade some of that sealing for a reduction in friction. That doesn't mean one has to idle the motor and "baby" it, that wears the sleeve without properly heat-cycling the motor, because without proper loading, the motor never COMPLETELY gets up to the proper operating temps; thus, the sleeve never expands fully to its intended diameter, and the piston/sleeve tries to wear itself into the wrong dimensions.

And now, here's the real-world example...Take a look at how R/C engine break-in stands work, and R/C airplane break-ins, for that matter. Both ways use full-throttle for break-in, with a propeller providing the load. Gee, why do they do that? And why does Adam Drake break-in his motors at WOT?
That said, you'll never blow your motor up idling through a few tankfuls or babying your motor, and again that's the main reason why engine manufacturers will continue to recommend those methods...They may not be the absolute best for longetivity or performance, but they are relatively fool-proof.

Also, I want to say that I'm not trying to piddle in anyone's Wheaties or anything like that...hopefully this will continue to be a civil exchange of opinions and facts. There's always more than one way to skin a cat, and I'm not out to change anyone else's minds...we're all free to do what we want and do what we feel is best. And since I have explored this subject quite a bit ;) , I'm going with what makes the most sense based on my education, experiences, and research.

Again, nice post AoD...I just don't agree for the reasons above.

-Greg

:beer:
 
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I don't see this getting out of control or a need for the warning 25. Very interesting and civil discussion going on here.
Both AoD and Judge bring up very valid points and I agree with almost all said by both and find it difficult to pin point the final answer.
Greg your comments and comparisons with ringed motors makes a lot of sense to me as I too have seen the changes with them and sealing/seating of the rings. But it is hard to compare the two types of motors with break in if you know what I mean. Just too many differences.
The comparison with airplane motors is more like it and the more I read and understand this procedure the more I like it. I think having a load on it compared with no load is better which was why I did no idle tanks with my friends motor. But then again both ways have worked out fine and like you said to each his own.
Nice thread and I find it very entertaining.
 
Just to keep my post clear Pineapple, I added "R/C" in front of "break-in stand". I see how that might have been confusing; I am not trying to draw any similarities between ringed and ABC engine break-in. Besides the principle of heat-cycling in and of itself, the two engine types share little as you said.
 
I understand exactly how you're thinking Judge. And to make it clear as well, I'm not gonna say you're wrong in any way. Just my knowledge of engines in general point to a totally different conclusion.

My biggest problem with that guys post was the fact that he generically pointed out that the manufacturers just make it easy on the user. I don't believe this in any way, personally. If you think about it, an engine running at WOT will produce maximum heat, yeah, but also any engine that is ran at WOT is causing itself the highest amount of stress that it can go through.

(Just incase it isn't known by everyone, WOT = Wide Open Throttle)

My biggest problem with this is the wear principles. Almost everything you can get that has moving parts needs a period of breaking in. Where all the small flaws are worked out and the parts fit perfectly. This is especially true for ringed piston engines, as the rings will not seat properly until everything is just right. This is where two stroke motors really change against four strokes.

Basing the idea off of compression, the ABC non-ring motor is the same way, without the problem of rings being in the way. HOWEVER, rings bring longer engine life, and higher compression results during the lifespan. Almost anyone knows that running a ringed motor at WOT is bad in the first hour of the motors life, because rings seat on the cylinder walls constantly. Friction being the evil side here, all said and done, the wear-in period will cause the rings to seat in a perfect fashion and vwala, higher compression = more power.

ABC non-rings are different in every aspect, but very similar indeed. This "pinch" spot has many similarities, however it is very different. Being a cone shaped cylinder, the piston requires oil/fuel to cause compression to be at max. The oil/fuel here actually act as the rings, and cause a seal when the piston is near the pinch. BUT, without rings to support the piston in a certain place, the piston has every chance of tapping the cylinder wall. This is especially true during break-in periods where the pinch is low, and the tolerances are TIGHT. Heat does cause the cylinder to expand and create sloppier tolerances, however this doesn't always hold true as it is still possible to have the piston touching the cylinder wall.

Consider the lean vs rich idea. Richer just adds more fuel to the mix, causing this sealing effect to be higher, where it doesn't really ADD to the compression, but helps keep the piston off the walls even more. Running extremely lean, reduces the effect, causes more friction, higher temperatures are a direct result. This is why the motor will actually lose lifespan during lean settings. Less friction = longer life, but with less power. The engine can actually struggle to keep ignition and this is due to the ignition cycle. However, that's not important for this discussion, so I'll end this part here.

Now, back to the topic, thinking of break-in periods. Wide open throttle doesn't necessarily induce higher amounts of fuel into the engine. It does however induce higher amounts during acceleration. This is the "blip" effect that so many people use for break in. Running at constant throttle just keeps the engine moving. One of the biggest reasons engines fail, whether it be ABC or Ring style, is constant wide open running. Where the engine doesn't have enough load to need more fuel. This is called high RPM, low usage. Picture a car, street automobile running at 100mph. The engine won't run any faster, but isn't pulling the car any faster. It's not requiring more power to pull the cars weight, and the other variables don't add up to being enough to drag the car down to this point. That's causing major heat, as the engine is running high rpms, however not working to potential. This is causing major heat and friction, and can cause failure rate to increase ten-fold.

I understand the idea with the propeller, as the engine would have the stress it would need for running at high RPM. ABC's work the same way as a ringed engine in this aspect. Thirsting for fuel, an engine that is undergoing pressure, from the propeller in this example, is going to be dragging more fuel through the fuel system to try to push the propeller to higher speeds. This power input, is actually good for the engine in respect. That's why the Aircraft engines last under pressure.

HOWEVER, there is a difference with a truck/car engine. Running at full throttle where the engine just can't achieve more RPM and the vehicle is going as fast as the motor can pull it; there just isn't enough stress on the engine. The engine will actually be lax, compared to with say, the propeller. This will reduce the engines need for fuel, and actually cause it to run leaner than it would with the propeller.

Engines work on two principles, Air and Fuel. When the engine is "lugging", or accelerating, it will drag as much fuel/air as it can through the fuel system as it can. (Fuel injection changes this aspect, but doesn't need to be discussed).

Now, during a breakin period, the motor will already be going through high amounts of stress, as the parts will be tight in the first place. I don't see how running at WOT would be of any assistance in this particular time. Idling can be damaging to an engine as well, however, it is easy to do and requires little work. This is true, but the engine doesn't go through much major stress, and idling in a specific spot decreases much of the engines cooling effects. So, the heating aspect is also there as well. If you think about it, an idling engine can actually run hotter then one running at WOT down the drag strip. The idling engine is getting no cooling, but the WOT engine is getting cooling from it's own movement. This mostly points to ambient temperature, however I'm not going into that.

Either way, I'm sticking with my idea, as it works well for me. Just remember, break-in is an important time of your motors life, and no matter how you do it, make sure you do it right. :) I must now leave for work, as it's a little after 5AM.

By the way Judge, good post. Makes for a nice debate either way. :)
 
Good info. AoD, what exactly is your breakin method? Obviously you disagree with the WOT method, but it didn't sound like you prefer the idling-thru-a-few-tanks method either...
 
Well, at most I'll usually let the motor idle for 3-5 minutes. Getting the wear-in done and over with. I hate seeing a motor choking on itself.

I'll run the first few tanks lightly, maybe the occasional full throttle blip, but nothing more than a quick fully opened carb then idle. I watch the heat, then shut down when needed. Once or twice a tank in a large tank, as with the savage. After 4-5 tanks, it's time to start tuning, without running hard. Then, after I get the engine running steady, I'll start working it in, getting the tune to the full throttle. Usually takes me ten tanks or so, but I start having fun at tank 5. :)

Idling too much can be harmful yes. That's why I only run idle for a little bit. I usually recommend others just to idle the tank, as usually newer guys tend to be way to throttle happy with new trucks. :)
 
Well, I realized that a discussion like this needs a little HPISF testing...so I took that part into my own hands.

I finished hooking up my brand-new LRP Spec 3 Saturday night, so Sunday I went out front, warmed the block with the wife's hair-dryer, and started driving. I just cruised it around a bit until it warmed up, made sure it wasn't 4-stroking rich on the throttle, and let 'er rip for 2 or 3 minutes before I shut it down. I even hit the 1-2 shift a few times!

And....





















Well...













>cough<











Nothing bad happened...I put it at BDC and let it cool, and repeated this five more times so far without touching the carb. The motor ran stronger and stronger each time, and the pinch still feels as tight as before I ever started it. I'm sure the con-rod is fine too, since I warmed the motor up quickly enough to expand the sleeve fully, thus relieving a lot of excess friction that the rotating assembly would have to be dealing with(Remember, cranks, bearings , con-rods, etc. DO NOT, and have never needed any break-in, just a little heat cycling).

So far, I haven't quite used two tanks of fuel, and the truck is almost pulling wheelies, even though it's putting out a ridiculous amount of smoke since I haven't leaned it out yet. Just to be safe, and since doing it more sure won't hurt anything, I'm going to do this a total of 10 times, and then start leaning out for power. From what I've seen so far, the power should be incredible!

I will continue to keep you all posted as to how the rest of the process goes...unfortunately it has rained out today, so I'll be back on it when things dry out in a day or 2. As it stands, this is my *new* break-in method...Whether anyone else tries this or not, it's cool with me, but it made so much sense to this lifelong gearhead that I just had to try it out and share with the forum. If anyone else does use this method, I would be very interested to hear how it turns out for you as well...post it up!
 
Props to you for giving it a try and sounds to me like it works just fine!
I will give it a go on my next new mill but I hope that won't be for quite some time as I have a new one now.
Thanks for putting this theory to a real world test.
 
One thing I'd like to add...

While BANKRUPTER and I were , uh, "discussing" this method last night (lol), he brought up a good point that I should clarify here. Bank thought I was thrashing the motor at max RPM's, and I can see how it could easily look that way from what I posted. What I didn't say before is that I am not attempting to reach or hold max RPMs at any point during this...however, I have been staying in the throttle past the 1-2 shift. As rich as it is right now, I very seriously doubt the motor could top out anyway, but I have no plans of trying that...After I'm done cycling it, then I'll lean it out and see what she's got. That is, once it dries out and warms up a bit here...
 
It took me a long time to even try heat cycling an engine. I don't think I could do it the WOT method if tried. I'm a baby I guess.....
 
Judge, props to you bud +rep as well. Good effort for going out and actually putting it to the test. I hope it works great for you man! I am glad it's showing power as well! Let us know how the rest of it goes too! :)

I just wish you had two lrps, so you could test/compare the methods. This would be the best way to actually see if it performs better or not. Two subjects following a similar life with different break-ins. That'd be a good project! I'm really wanting to see how it turns out! :)

And good luck with the rest of the break-in! I'm rooting for you! LOL It'd be great to hear that you've had good luck with everything! :) Heck, I might even give it a go with a new motor when I get one!

You rock for trying it Judge, you really do! It takes some guts to put 15--180 bucks on the line for a good answer! :)
 
THE JUDGE said:
Bank thought I was thrashing the motor at max RPM's, and I can see how it could easily look that way from what I posted.
Click to expand...


As was I, as was I. Running a midrange throttle shouldn't do much damage at all either. Well, RPM for that matter. I wouldn't personally want to reach over 20,000 myself, but we'll see how it goes with your new mill! :)
 
THE JUDGE said:
I've been doing a lot (maybe too much) of reading regarding 2-stroke ABC engine break-in, and I found this method here:

http://www.rcuniverse.com/forum/fb.asp?m=6811864

To be perfectly honest, this method makes far more sense than any other way I have heard about. What I'm wondering if any of you have heard of or used this method, and anyone's opinion on such.

TIA
Click to expand...

I used a WOT method years ago (suggested by the points champ at the time and I was a n00b) when I was racing 1/8 buggy. Never had a problem with those engines.

I think the idea is that you don't want the RPM's to remain constant for extended periods being overly rich or overly lean.

Sounds like something I've heard back from my 1:1 racing days (break-in for our drag car was a warm up and oil change at the shop and then the burnout!). It ran a little more than that, but you get the idea.

I used this method recently on my RBMods SureFire 32R and it's been all good so far. Half-gallon through the motor and it's a *BEAST*!
 
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