RE: Importance of engine break-in ?
 

HI this applies mostly to ABC and RINGED glo engines THE break in period is to polish all moving parts to seat together-stay away from any lean running at this time-and ALWAYS as heat will damage the mating surfaces-(the metal will also get harder from the hot to cold temp changes ) run the engine for a while and let it cool completely-i like to keep the piston on the top of the sleeve during the cooling period -set the carb to hold and run at a high and low needle valve setting- try this -with the engine at a smooth idle-squeeze the fuel line-if you hear the rpms increase you are rich at idle-(as it s/b )-run the engine to full throttle-sqeeze the fuel line -you should also hear a slight RPM increase (s/b about 200-400 RPM )use a tach to run in the manufacturers recommended RPM range for the engine (and prop it for just that )-get the engine into the air A>S>A>P as it is air cooled and should be subject to the prop loadings that take place in the air- do not try to set a needle valve if an engine is very hot -let it cool first-then start again-do not tighten any engine bolts on a hot engine-let it cool first- use a fuel with some castor oil for the added protection it affords -MORGAN 15 % is my fuel of choice -i am handling glo engines for 24 years-my first ones are still in good running order-been following CLARENCE LEES advice since the beginning-do run the engine dry and use after run -to prevent rust on bearingsdo not allow any air to get into the engine- from gasket surfaces ( head -carb ) or from a leak in a tank or fuel line it will cause HEAT and damage the engine- the sign a leak is present -will be an engine that starts to run lean -at a needle valve setting -that it always ran just perfect atdo watch for this condition-it is your only warning and chance to prevent some damage to a strong glo engine

RE: Importance of engine break-in ?
 

What part of the higher you go the colder it gets don't you believe, then add movment to that and it really cools off in a hurry, Ya ever hear of the wind chill factor? ,honest its there when the weather is 90 degrees out. Were not talking what if the cowl is wrong or what if this is wrong or what if period. I said any engine will run cooler in the air and its a proven fact, do a search if you don't believe me. I have seen a new engine ruined on the bench by running it to lean as well as running a ABC to rich. Both engines was toast after a couple of tanks due to improper tuning. I have yet to loose a engine in the 40 plus yrs I have been doing this, so I think I must be onto something right .

RE: Importance of engine break-in ?
 

Gosh, you are right, cyberwolf! I went up on top of my house today to sweep off some straw and it was freezing up there! When I got back on the ground it was 90 degrees F again. Absolutely amazing. I majored in Aerospace Engineering way back in the 60's and all that temperature/altitude stuff hadn't been discovered yet, Thanks for the info!;) Now, after all these decades of attempts I may be able to get an engine to run.

jess

RE: Importance of engine break-in ?
 

Quote:

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ORIGINAL: Cyberwolf

Any engine will cool better in the air, And again if your engine is set where its supposed to be you won't have a lean run in the air.

---

CW,


This is not necessarily so. Using a smaller diameter prop during static break-in will reduce the load imposed upon the engine...

...In fact; during static break-in, all the prop needs to do is to provide flywheel effect, so the engine will go on spinning and to provide just enough air-flow, so the engine's heat would be kept at bay.
If break-in is done in flight, the prop will also be required to produce effective thrust, that would keep the plane flying along...

I've just convinced my self. That sentence is necessarily incorrect and the safest and best way to perform a low-load break-in, is on the ground.


But... a very low-load is not always what you want during break-in...
For a tapered-bore engine, you need the engine at its normal working temperature...

For a ringed engine, you need to keep it cold only for an initial tank, or two. This, to remove the larger 'ridges and valleys'...
Afterward you need 75-85% load, to properly bed the ring(s) and the sleeve together and to prevent any onset of glazing on the sleeve wall...

RE: Importance of engine break-in ?
 

What's interesting about Lee's ringed method is that you are basically flying a C/L stunt type routine in which you break the engine back and forth from 4 to 2 cycling via large, gentle maneuvers.

David

RE: Importance of engine break-in ?
 

Engines don't have sweat glands so wind chill isn't a factor in their cooling.

You could break in an engine in the air but only if you were absolutely certain it was holding the correct mixture the entire flight. That's much easier to do on the bench especially as the fuel level in the tank goes down. I might add this really only applies to an ABx type engine where the best initial mixture is around where the engine is just breaking from a 4 stroke into a 2 stroke so there's enough power to get off the ground. With a ringed engine in a slobbering 4 stroke (initially) you could end up doing a fast taxi around the field :).

RE: Importance of engine break-in ?
 

My experience is that the engine runs hotter for the initial break in from the friction of those larger ridge's and valleys, so you run it colder to prevent the engine from getting to hot, especially where the ring and sleeve meet. One can keep the engine running at a normal temp with just a slightly richer temp, but to keep the rings at a normal temp requires an even richer mixture.

RE: Importance of engine break-in ?
 

Some have sweat glands, but we call it a venturi. When the carb venturi to rotary valve distance is short it will spray fuel on the engine, giving it some wind chill effect. But not very major on most engines and often only at part throttle.

RE: Importance of engine break-in ?
 

Well.

I've done 'em both ways. A tank on the ground, then fly slightly rich. Full power won't be available the first few flights/tanks. Run a few tanks on the ground in a stand to get familiar with the engine. Full power won't be available for the first few tanks. They both work.

We used to use break in newly overhauled radials in a test cell with an unusual prop/club that had 4 very short/stout blades with steep pitch.

Terry in LP

RE: Importance of engine break-in ?
 

Aside from "wind chill", CW also said "What part ofthe higher you go the colder it gets don't you believe..."

Of course it does indeed get colder with altitude, something like two degrees per onr thousand feet as I recall, (not to mention the change in air density), but I doubt that a temperature change of less than five degrees will dramatically affect the running temperature of an engine. That being said, it seems that break-in procedures, like castor vs synthetic, after rub oils etc. are matters of deep moral concern to some. Far be it from me to attempt to influence anyone's most deeply held and cherished beliefs.:)

jess

RE: Importance of engine break-in ?
 

I had a thought in reference to bench running. How is a tied down airplane any different from a bench run? I mean, tie your plane securely to a bench, up out the dirt. Okay, you're exposing your radio equipment to so some unneeded vibration.

The thing is, the carburetor/tank relationship effects tuning. If you run an engine on a bench, you've already established one engine/tank relationship, and you've tuned accordingly. When you transfer the engine to the plane, you can try your best to get the tank on the same level. Invariably, the setup will differ in some subtle way, and you'll have to retune all over again. You're duplicating your efforts. Why not establish the correct carburetor/tank relationship once, in the plane, and then leave the mixture alone forever? Its one less variable to contend with.

Tom

RE: Importance of engine break-in ?
 

We can go back and forth here forever ,you break in your engines the way you like and i'll do the same.
The largest factor I have seen to the demise of any engine is the fact, the person that was useing it didnt have a clue as to how to set it up. On the bench or in a plane.

RE: Importance of engine break-in ?
 

Tom I totally agree with you here, when I run the initial tank or 2 on the ground I make sure the plane is up off the ground and the radio is off, unless im changeing the RPM's. Things have changed alot from the old days of the Fox and K&B engines where a long breakin was required. Todays engines are not only made from different materials but made better in many ways , in short things fit when new.

RE: Importance of engine break-in ?
 

Its not a factor eh! ok then I should see the same engine temps say on a 100F degree day as I will on a -25F degree day correct?

RE: Importance of engine break-in ?
 

Quote:

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ORIGINAL: Trisquire

I had a thought in reference to bench running. How is a tied down airplane any different from a bench run? I mean, tie your plane securely to a bench, up out the dirt. Okay, you're exposing your radio equipment to so some unneeded vibration.

The thing is, the carburetor/tank relationship effects tuning. If you run an engine on a bench, you've already established one engine/tank relationship, and you've tuned accordingly. When you transfer the engine to the plane, you can try your best to get the tank on the same level. Invariably, the setup will differ in some subtle way, and you'll have to retune all over again. You're duplicating your efforts. Why not establish the correct carburetor/tank relationship once, in the plane, and then leave the mixture alone forever? It's one less variable to contend with.

---

Tom,


Starting a new engine can be a particularly nasty experience...

If you install your new engine in your new model for break-in, you would necessarily expose this model, to the same 'quirks and idiosyncrasies' that the engine exposes you...

Also, an engine; ANY engine, must be mounted so the setup places the tank as close as possible to the engine (unless you have a pump/regulator) and with the carburettor's jet and the same level as the tank's center-line (with the model in level-flight attitude). A test-stand setup should be very close.

The reason your engine has carburettor needles, which you can turn at will, is because you are expected to do so... Whether it is done to compensate for changing ambient conditions, or for a different setup, or to achieve the engine's primary running setup...


If you realistically expect your setup to remain completely the same, from the end of break-in, to kingdom come; just because you broke the engine in on the plane... well, you're probably not in the right kingdom...;)


Face it.
1. A break-in is much safer and easier to do on the ground and at your immediate control than it is in flight; obviously not at your immediate control.
2. A break-in is much safer and easier to do, with the engine mounted in a test stand than with the engine mounted on your new plane.


While I strongly respect Clarence Lee and his elaborate procedure; I believe real modelers, who do make mistakes, should stick to the ground procedure, for the initial break-in (three tanks/30 minutes in a ringed engine)...

RE: Importance of engine break-in ?
 

Face it.
1. A break-in is much safer and easier to do on the ground and at your immediate control than in flight; obviously not at your immediate control.
2. A break-in is much safer and easier to do, with the engine mounted in a test stand than with the engine mounted on your new plane.


Ok let me get this straight ,your saying that a engine is safer in on a bench than in a plane , does the bench have a guard on it to prevent you from getting your hand in the prop ??? NO they dont . Are you going to fly that bench? again NO . are your needles harder to get to on the bench or the plane, depends on how you made your setup on the plane. I make mine easy access but have seen a few that was a real bugger to get to so the bench wins this time.
I can't think of one good reason why its safer to breakin a engine on the bench versis the airframe if you have a proper restraint on the airframe , Standing over it useing your legs is not what I call a proper restraint.
So why is it so much safer to break in your new engine on a test stand ???

Other than pissin off your neighbors and creating alot of smoke and oil on the walls of your shop I see no reason to run a engine typical 2 0r 4 stroke on the bench unless you are trouble shooting the engine or just like to play.
BTW if you have trouble starting and running a new engine your doing something terrible wrong. Todays engine are very user friendly and don't require the hastle of yester years heartachs trying to get one to run.

I still say a engine needs a certain amount of load on it to seat the ring in properly and nothing you or anyone eles is going to say thats is going to change my mind.
I do agree that a lighter prop can be used for the initial breakin and even used to fly the plane with .
I have used a breakin very much like the one you have posted all over the place in here on ABC/ABN engines for yrs, since the first one I ever bought in fact, Before I ever heard of you or RCU for that matter. That was a 46 FX and it still runs perfect today, and does those RPM's you say it cant do also *LOL*
But again after a tank or 2 on the ground to get the needles where I want, and up it went. I don't tune for max RPM's I tune to make sure it's on the rich side but still a strong 2 stroke mode and will stay running W/O a dead stick and go from there. I also say that a engine will run cooler in the air, agreed 5.4 degrees F per 1000 feet is all but counts and is not the whole pic, wind chill factor call it what you want but its there when air is moving over and around the engine or anything for that matter.
I think thats why they call these engines AIR COOLED !!! I defy you to tune a engine for 80 degrees F and try to fly it in 30 degrees F weather W/O retuneing the needles don't try tell me air temp dosen't have a effect on both the engines temp and airfuel mixtures because it certainly does. Put some onboard telemetry on your engine and fly it then come back and report where it runs the coolest at ground or air.

WHATS THE BIGGEST CONTRIBUTING FACTOR FOR A DEMISE OF A GLOW ENGINE? or any engine for that matter?

RE: Importance of engine break-in ?
 

hi i think we s/b considering engine unloading in the airalways thought you will pick up 1000 rpm in the air -over the rpm tached on the ground- but just lately was told could be as much as 2000 rpm- so this will also effect the engines break in- as the engine in the air is now performing in the rpm range it s/b- which is not the same as on the bench- more rpms produce more power and heat- this will be allowing the engine to break in and run under the actual conditions you will be dealing with in your daily flying- so get the engine into the air as soon as it will hold a good idle and a good top end rpm-the time it takes to get reliable needle valve settings will vary with a given brand of engine-os needs little time(one tank ) -while my 51 super tiger required the most (4 tanks )i add a small amount of castor oil to my brake in tanks- to help smooth the metal surfaces-i have done a lot of engine rebuilding over the years-and find the straight syn fuels (morgan-green ) to cause much more wear (than morgan omega -pink- -that has some castor oil )

RE: Importance of engine break-in ?
 

CW,


Although safety is of utmost concern in this hobby, it is not the reason some recommend a flying break-in.

The concern of break-in technique, is its safety to the engine's innards, not to the operator's fingers, or to anyone's physique...

It is needless to say that if the break-in is done on a test-stand, it must be firmly tightened to a solid object, so it cannot 'fly-off'...
The same goes for the 'poor' model that its owner decided to punish, by doing the break-in on it.

After you got the engine started, any adjustments must be done from behind the prop - not over/around its spinning blades.

Any proper test-stand will allow this, at a much lower risk to anyone's fingers, or self...
A model may not be that user-friendly, if the engine is installed and access is somewhat limited.


Once a prop has created a vortex around the engine; for all practical purposes, it is flying... Its running temperature is set using the needles and this temperature is virtually the same; whether it is running in 110ºF of sweltering heat, or at -25°F.
Despite the great difference in air temperature, your car's coolant temperature is the same 195°F; in the dead of winter and in mid summer.
It is just controlled differently...

And, of-course the setting of the needles will not be the same in both hot and cold conditions.
The engine will be running cooler, neither on the stand, nor in the air; but on the stand the user can make adjustments, which would be impossible when in flight, so for the 'flying break-in' the user will be advised to set it a bit richer than ideal, to avert a lean condition that may develop during the flight.

This may, in turn, prolong the break-in process...

On the ground, the user can set the needle 'on the spot' and change the settings on the run; if they prove to be a bit too rich, or too lean.

In the air, the setting you take-off with is the same as the one you land with... You cannot make changes during the flight, to compensate for the advancing break-in, that you can easily make on the ground.

RE: Importance of engine break-in ?
 

Calm down Cyberwolf! I will always defend your absolute right to worship, believe, think, and run your engines as you please. If your models transition from +100 to -25 degrees during flight I commend your tuning ability.

There is an obvious solution to not getting smoke and oil on the walls of your shop while running them. DO IT OUTSIDE!. There are obvious health benefits to out door running as well. I am disappointed that did not occur to a man of your great intelligence and experience.
[:o]
BTW:
"WHATS THE BIGGEST CONTRIBUTING FACTOR FOR A DEMISE OF A GLOW ENGINE?"

Hard contact with the planet Earth.

jess

RE: Importance of engine break-in ?
 

Im a calm as can be and your Answer is WRONG!!!!!!!!! HEAT KILLS MORE ENGINES THAN ANYTHING !!!!!!!!!

Nobody said anything about that much of a drastic temp change all at once but you sir. its obvious you have delt with far more engines than I have . Btw just how many engine do you own that actually run .
Your showing off your IQ with those sort of statments. BTW why would anyone need straw on ones roof. Sort of a fire hazard isn't it?

RE: Importance of engine break-in ?
 

I suspect that many of us (Old Farts) are still thinking in terms of breaking-in lapped piston engines of many years ago. They did require a good break-in for top performance, however I've mounted many a McCoy, Fox and K&B lapped piston engine on my models and just tuned it for max rpm and let it go on my control line models. They seemed to "break-in" just fine without all of the blubbery rich four-stroking that the old timers of the day recommended.

Later, as I became a little more educated (read more model magazine articles) I began babying my engines of all types. Why? Well, because the engines did seem to run better and feel better, plus I just enjoyed running engines and when it was too windy to fly, I'd mount up several on the engine test stand and have at it.

Today's engines are a far cry from what was available back when I was a kid starting out. You can fly-in most engines as long as you start out with the needle valve rich enough to still be running somewhat rich at the end of the tank of fuel. What you can't do is count on the throttling to be 100% reliable. So, think out your break-in flights before hand so as to keep the model upwind of the landing site and with enough altitude to make it back to the field. Good luck.


Ed Cregger

RE: Importance of engine break-in ?
 

[

Glad to hear you are calm, CW. I was concerned about you for awhile, especially when I read the bit about running engines indoors.

As to the number of engines I have that actually run, I must confess I am not sure. I'd say over two hundred but less than two hundred and fifty. Mostly glow but a dozen or so old ignition. I do have a few I have not run but I am confident I will remedy that.
I have never ruined an engine by overheating, but I have lost several to crashes. If your experience differs perhaps you are running too lean?

Now to your question about straw. I am glad you asked as you clearly are uninformed and may someday need to know. No one "needs" straw upon their roof, unless, of course one has a straw roof, as is common in some parts of the world. In my case, my home is surrounded by a form of vegetation known as "pine trees". (I also actually grow the trees on a farm) These trees form "needles" which as they age and die turn brown and fall in the form of "straw". I suppose straw could become a fire hazzard. That is one of several reasons I periodically remove it from my roof.

This has been a most enjoyable exchange, CW. Thanks

jess

RE: Importance of engine break-in ?
 

Thanks for the input Dar. I see your point.

Tom

RE: Importance of engine break-in ?
 

So, we have some strong opinions in here. That's fine.

Some points still to be made?

ALWAYS consider the manufacturer's break-in recommendations! If something goes wrong and you weld it into one expensive paperweight, you might consider blaming the mfr, and go to them for "satisfaction." (Some comments in other threads suggest that some of us DO think that way.) A mfr will be able to tell, and fairly easily, if the engine has been brutally abused, but nowadays would probably cave to prevent "bad press."

I also check that a new engine has been properly assembled... You'd be surprised at some of the mass-production goofs I've caught before first run... And, again, I've seen occasional comments from people unhappy with an expensive engine when they found a head bolt or backplate bolt hadn't been properly tightened. Well, duhh, didn't you even LOOK at the engine before operating it?

Proper torquing is important, too. You'd be surprised if you loosened all head bolts, checked how free the engine feels that way. Carefully torque the head back in with a consistent sequence, checking that you haven't introduced any bind, after each 'rotation' through the sequence. Modern engines are more substantial than those of the 1940's and 50's, but they can still suffer from bad torquing - consider: brass is not as hard as steel and most sleeves today are based on brass...

Type of engine makes a difference - and the mfr generally suggests what they are confident will work reliably. Examples: Some engines have synthetic oil only recommended; some recommend 0% nitro fuels; some say bolt it in and go fly... The differences I'm familiar with after almost 60 years of using glow, diesel and occasional spark engines seem to work just about every time:

Lapped iron pistons in steel sleeves - bench break-in, outdoors. Significant castor oil % in the fuel. Short runs - just up to thoroughly warm - and good cool-down before the next noise. Slobbering rich for first one or two runs, then gradually leaner over the next several. (First, polish in the rod bearings. Then go for the longer term heat-cycling and burnishing-in without galling anything.) At first sign of anything wrong developing, it is much easier to yank the fuel line off a bench-mounted engine...

Ringed engines are almost the same, except that the critical wear zone on the piston is only the height of the ring(s). If rod and shaft wear in properly, that small ring land shouldn't need as much run time to get durably happy...

Non-ferrous engines (Aluminum/Brass/Chrome, Aluminum/Aluminum/Chrome. Aluminum/Brass/Nickel), imho, still need at least one brief rich run to help the rod bearings run-in. THEN do as most mfrs suggest: several brief runs just below 2-cycling or warbling in/out of a rich 2-cycle. Cool-down between runs. DON'T wind in the needle (HS needle with RC carbs) until RPM sags! Sagging RPM can indicate heat expansion is pushing fits toward metal-metal contact. We have oil in the fuel to prevent that...

Why the difference? As Dar and others cited, modern CNC techniques allow cutting basic dimensions so that proper clearances only occur when operating temperatures expand the piston and sleeve the designed amount. Overheating these, when new particularly, can force metal-metal contact, which will gall finished surfaces, or wear away the designed dimensional fits. Loss of performance and power may not be a lot, but that's no way to help an engine work well for you for a useful length of time.

Engine temperatures: Engines reach about the same running temperatures pretty much regardless of ambient temps. The heat comes from burning the fuel. The complete cooling envelope limits the top temps reached. Our engines are partially air-cooled. Other cooling processes include vaporizing the fuel through the venturii or carb. Methanol chills significantly on evaporation, and the crankcase directly under the carb or venturii feels cool even on an engine running pretty hard. Do not try this on an engine buried in the nose of a model! However, it is safely accessible on a bench. The chilled zone adds a nice heat sink that doesn't warm from running. Another process is heating the oil going through the engine. Most of it doesn't add much heat to the combustion, even if some synthetic does burn away. Castor hardly ever burns, so it leaves the engine with the heat it has picked up. ...Physically carries those calories somewhere else... (Castor can char, and coat the carefully generated dimensions on the sleeve and piston, so it isn't always best as the only oil for non-ferrous, CNC produced engines. It can be good in a blend with synthetic oils, which act as detergents to reduce charring and buildup.)

A decade or two ago I was "breaking-in" numerous OS mid-size engines for an acquaintance's project that needed unquestionably settled-in ready-to-go engines. As many have commented, and occasionally the instructions will suggest, power and economy improve dramatically over the first 5 to 10 minutes of proper running. The first runs made for difficult starting, hot running and considerable dark matter flushed out in the exhaust oils. Economy was also pathetic... As these were modern, non-ferrous CNC made engines of well-deserved good repute, I understood the initial runs accomplished much burnishing of remaining machining tool marks and surfaces. (The machining was close, but not perfect.) Economy, handling and power rapidly improved as the oil cleared. BTW, I almost always hand-start engines on a test bench. It's a better "feel" for the engine's condition. Still have all my fingers, and only an acceptable scattering of small scars. ...Cautionary reminders to be careful, that I never got from an electric starter...

...Engines continued to improve over some additional running. The rate of improvement declines as you get it settled in. No sense just burning fuel, gassing neighbors and listening to that sweet music any longer than the engine basically needs.

This has also been the norm for several of my own OS and other non-ferrous modern engines. At least they reach a usable plateau much sooner than the iron-in-steel setups, as those metals do not have the higher expansion rates that allow cutting-in designed tapered fits.

For RC Carb engines, it makes more sense to set idle and transition AFTER the initial wear, as heat, handling and economy all shift as the engine approaches its break-in plateau. Mfr instructions often indicate that you should either wait until after a half-hour or hour of running time to achieve final carb settings, or at least recheck them after a similar runtime total.

The flying I most enjoy is CL Precision Aerobatics, where absolute engine reliability and consistency are crucial. I still like the sound of the 4/2 break style run, but recognize that there are more of the modern engines NOT designed to do that. Several of my flying buddies try to force the newer 'greyhounds' to 'mush a dogsled...' Recent engines can be controlled more easily by operating them more like what they were designed for. For CLPA, flatter pitch props and more RPM restrain excess speed, AND fit the non-ferrous engine design package better. The older engines operated nearer torque peak - around 9000 RPM - and weren't revved to anywhere near max power. With flat pitch props, A** engines are at higher power, but mixture limited, RPM, loafing along with that power on call if needed for maneuver loads...

RE: Importance of engine break-in ?
 

Very good post, Lou.

jess