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Old 11-16-2007, 12:21 PM   #16
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Originally Posted by jbrow1 View Post
I just broke an engine in two weeks ago here in michigan on a nice cold windy day. I used two layers of foil around the head and still had to keep my stocking hat over the engine to keep any heat in it.
i dont think ill be using a heat gun, but i will use a hair dryer, ill also keep it inside so it doesnt get cold, ill start and run it in my garage, itll be better then outside in the wind.

so im going to need to wrap tin foil around those 10 thin little cooling plates??

ps: whats a stocking hat?
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Old 11-16-2007, 12:21 PM   #17
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Hehe, I started in the garage as well until it got to smoky in there.

Stocking cap would be my toque, canadian for the hat I wear on my head. I married a canadian girl and that's what they call em.
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Old 11-16-2007, 12:24 PM   #18
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Originally Posted by what happened? View Post
i dont think ill be using a heat gun, but i will use a hair dryer, ill also keep it inside so it doesnt get cold, ill start and run it in my garage, itll be better then outside in the wind.

so im going to need to wrap tin foil around those 10 thin little cooling plates??

ps: whats a stocking hat?
If you want, you can run 2 tanks on the first start up. Just fill the tank when its almost empty to keep it going. Let it cool down, then run three tanks back to back with a little throttle blipping and adjust the needles as needed. Once you get it rich enough to keep running with smoke from the pipe and keep 200+ temps, you will be leaning the needles from that point on. Mainly the low needle. Once running on the ground it will be low needle and then high needle to get it to clear out the revs.
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Old 11-17-2007, 04:51 PM   #19
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Default The correct way..(once and for all) !!

I have done alot of research on this , and I have found the one way to heat cycle engines that made sense...read this and you WILL understand why this is the correct way..."Idling an engine, letting it run slow, 1/4, 1/2 throttle is all
incorrect. You want WOT after it warms up. YES WOT, even when it is
brand new. This is in order to bring it up to the temp and fit the
sleeve was designed to run at. Anything less and you are just leading
your engine to an early death.

Yes, running at WOT slightly rich, but not 4 stroking rich is the
proper way to do it. This explains the proper way and WHY it is the
proper way. Here is some further explanation I wrote a while ago for
newbie nitro guys that were still doing that incorrect idling method:

As for break-in, there is a whole lot of misunderstanding about this
and basic engine operation. I have read and studied a lot of
information on this and also by Dave Gierke who writes in RCCA and
Model Airplane News (also by AirAge) about RC airplane and buggy
engines and he's an expert. As well as Paris Racing, Stephen Bess,
Clarance Lee, etc, in the research I have done over the last few
years. It will take some time to convince yourself to bring a new
engine to WOT but when you start to understand it and why it is
correct, you will realize just how many people are completely
breaking the engine totally incorrectly.

Its important to learn the theory about how these engines run (2
stroke ABC, ABN, AAC), and how to break-in, especially because I see
WAY TOO MANY people using the wrong procedure of idling many tanks of
fuel through the engine. That is unnecessary and damaging which I
will explain. Although we use the term break-in? by its word alone it
is misleading because people wrongly assume it means to slowly and
gradually bring an engine to tune by idling tanks of fuel but you
will see why this is incorrect and unnecessarily wastes fuel too!
Please be patient and read further to understand.

These engines use a sleeve around the piston to make the seal (piston
doesn't have a ring) and it operates properly only with sufficient
heat so that the sleeve can expand to its designed operating size and
fit. All engines will be tight, especially when new, so on the
initial runs, you want to have it get up to temp, so it can run how
it is was designed to. By idling tanks and tanks through, overly rich
and cool, the sleeve just wears MORE against the piston because it is
not hot enough to expand to its operating size. And by doing that you
are prematurely wearing out and ruining your engine. The
piston/sleeve is designed to operate at running temps. Not doing this
by running cool and rich on the bench leads to premature wear. By
idling away tanks of fuel I GUARANTEE you are doing more harm than
good. As long as the engine is warmed up first, you dont have to drag
out bringing it up to temp when it is brand new. It wont hurt or
damage the working parts. These engines are very simple 2 stroke
machines. They do not have extensive moving parts such as valves,
cams, lifters, springs, etc. (like 4 strokers) so all this extra
gentle, rich, cool operation is completely unnecessary (and worse it
is harmful). HOWEVER, the sleeve around the piston can be a delicate
thing to maintain and it is not forgiving of improper treatment. And
improper treatment of a piston and sleeve is running it at a temp it
is not designed for. (either too cold or too hot, both are just as
detrimental) Most often this is done by running it too rich which
makes it too cold because the rich mixture doesn't generate enough
combustion heat for proper sleeve expansion. Just as damaging can be
an excessively lean run. If it is run overly lean for any length of
time it will destroy the sleeve. (that is why fuels with castor oil
as part of the lube mix are very good because they tolerate the too
high heat of a very lean run and will help to save the sleeve if it
is not run too lean for too long. but avoiding a lean run is
essential when you know enough enough about engine tuning to avoid it)

Running a 2 stroke engine slow and rich makes it '4 stroke' which
means it fires every other revolution, and that generates even less
heat. It causes damage and wastes fuel as well! Using a fan is
absolutely not necessary on it. Most important is to 'heat cycle' the
engine at least 10 times to relieve the parts of manufacturing
think break-in should be called initial Heat Cycling?instead so that
people understand what and why they are doing it.)

You run the engine in the car for 2 - 3 minutes at full throttle
(yes, WOT, dont baby it), ideally on a smooth paved level surface,
after briefly warming up of course, and then shut down and repeat
after the engine has fully cooled. Let it cool down completely. Heat
cycling is the name of the game. You want it to come up to temp for a
brief time, and cool down and repeat. After shutting down, adjust the
flywheel so that the piston is at BDC (bottom dead center) so that it
does not get stuck in the contracting/cooling sleeve, as can often
happen. (If the piston should accidentally get stuck in the sleeve,
preheat the cylinder to free the piston from the sleeve.)

During these initial runs YOU WANT the temps to be at least 200 F but
not above 230-250 F. After break-in, running temps above 230F is
fine. (in fact nitro engines perform best when run 250-300. below
those temps they are less efficient and less powerful. However, going
by the mixture is more important than trying to measure temp with
heat guns, etc. which you may wind up doing inconsistently. The
mixture setting on the High Speed Needle is critical in the first
runs. It should be a rich and not lean setting. However it should not
be so rich that it 4 strokes.

Also, to start a brand new engine it is very worthwhile to preheat
the engine with a heat gun or hair dryer if it has a very tight
piston/sleeve fit and you are having trouble turning it over to start
it up. This will expand the sleeve some, and when you turn it over
the piston will not excessively rub, or even get stuck in the sleeve
(as sometimes can happen). Preheating really works well. You do want
to run it on the rich side, but you want it to come up to temp also,
just not more than 2-3 minutes in beginning runs, in order to keeps
temps around 230F. Listen carefully to the exhaust noise or note? as
you do not want it to be ? stroking? If it is, it needs to be leaned
slowly until it runs 2 stroke. You can tell it is 4 stroking if it is
very boggy?and hesitant?in acceleration and running. If it is making
that burbling?sound then it is 4 stroking which means it is running
too rich and therefore too cold.

Everyone thinks they have to run it super cool and check to be sure
temps are low. That's not what it is about. The reverse is true! Cool
operation is damaging operation. Little, if any, break-in will occur
unless it is heat cycled properly.

The manufactures cant make a piston/sleeve turn over smoothly at room
temp, because when the engine runs the sleeve will expand and there
will be no seal at operating temp. See how that makes sense?!

So preheat it if necessary and don't run it cool, and heat cycle it,
and you'll be good to go! After you have done this several times then
you can gradually lean out the HSN to get best performance, but it
should then be richened up just rich of peak to ensure it lasts long
too. Running it at max peak rpm will lead to the shortest useful life
of the piston and sleeve. If racing that is fine but if you are just
playing you may want to run just a little richer than that peak
setting. After the HSN is set then it is time to set the low and/or
mid range needles and idling setting.

I see a lot of people idle the engine for a tank and then they let it
cool off thinking that they are "heat cycling" it. However, because
they are not running it up to WOT it is not generating enough heat to
be of any use to a breakin/heat cycle. So, inadvertently by idling
they are just letting the engine sleeve and piston wear away from the
cold tight fit that they are allowing to happen when idling away on
the bench. Research has shown that basically no breakin effect takes
place AT ALL unless the engine is allowed to come up to operating
temp for 2 minutes. So if you are idling away and then let it cool
there is zero breakin/heat cycle benefit. But if you want to wear
away the sleeve and piston fit then idling will definitely do it for

I hope this is helpful!!

P.S. If you want to hear it from him, read Dave Gierken article in
the January 2002 issue of RC Nitro magazine! "
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Old 11-17-2007, 10:33 PM   #20
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I run the engines rich, but maintain 200+ deg (block the head from cooling and add a heat gun if needed). The reason for running rich is your adding more oil and fuel to wash away the metal from the break-in. I always high idle the first tank, not regular idle. Don't get that confused. If you WOT the engine though, you will need a rod a lot sooner than you think, plus your pressing out the oil from the crankpin, making it out of round or wear quicker because of the extra load on them at WOT during piston/sleeve break-in. The idea of break-in properly is to seat the piston to sleeve, BUT to also not stress out the rod and bearings. I can WOT break-in an engine, but I can guarantee you that it will need bottom end parts alot sooner than you think. There is a balance to the break-in process. Most engine guys will change the rod after about a gallon of fuel, because they know the rod bushing has taken a beating from the break-in. I have a "break-in" rod just for this.
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