Heat Cycle Breakin Method

Where? I see no method! I'm losing my mind! *falls out of chair and runs away screaming*

Sorry... URL has been updated...

is there a better copy of that somewhere? Kind of hard to read and blurry.

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.

OK, fixed the link again, to a larger, clearer version...

Thanks! Much better. My new engine should be here wednesday and I should have my buggy built by then.

It makes sence.



:buggy1:

would this work for none OS engines?
i have a force .26 coming tomorrow should i use that break-in method?

I want to add to this, because there is a decent flaw. On many engines, they require a good gallon or more in order to safely break in the engine. Sure you can heat cycle them, but they are nowhere near ready for the track just yet... they need to be babied for the first gallon.

No engine is safely broken in UNTIL you can take out the glow plug and turn the flywheel by hand, let the piston pass the top dead center in the sleeve. When you don't have any significant friction or when it feels just a little snug, you can start leaning the main needle incrementally in small steps. After its tuned, its ready for the track.

rccars411 said:

I want to add to this, because there is a decent flaw. On many engines, they require a good gallon or more in order to safely break in the engine. Sure you can heat cycle them, but they are nowhere near ready for the track just yet... they need to be babied for the first gallon.

No engine is safely broken in UNTIL you can take out the glow plug and turn the flywheel by hand, let the piston pass the top dead center in the sleeve. When you don't have any significant friction or when it feels just a little snug, you can start leaning the main needle incrementally in small steps. After its tuned, its ready for the track.

Click to expand...

While I will agree that it takes most engines a good gallon to really get broken in, I've done the heat cycle and had my last three motors on the track by what would be the third tank or maybe 20 minutes of overall run time. They all scream, and show no signs of tiring out. Hell my P5 had over four gallons on it and it couldn't be turned over by hand.

I agree with Jet. I have been using the heat cycle method for a long time now, and NONE of the mills I broke in this way retired early, heck, I still have most of them and the ones I do still have run like beasts, and still have a ton of compression. I do agree though that once they hit about a gallon they really came alive.

Heat cycling is god's gift to engines... but the engine will last even longer if you baby it after cycling it... until your down to a slight snugness with the glow plug out of the engine. On engines that have a super tight pinch, you'll kill em if you dont, even after heat cycling.

you know I still consider myself new to the hobby but not new to engines most all engines two stroke need a breakin and have a sertain spot they will run best on the tuning area but you could get 20 to 30 different peoples opinion on how to properly break in a nitro motor and they will all be different this has been and will always be so to this do what works you may ruin a couple of motors trying to come up with the best way but if you dont have the money to be in this hobby then maybe you should stick with electric!!!!!!! just my two cents

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

its a long run on sentance. It just needs some punctuation.

But I think what his statement amounts to is "if you ask 5 people how they break in their engines, you'll get back 5 different methods". I've seen that posted in magazines, but in reality, most guys who have been in the hobby heat cycle it or WOT break in.

savagecre said:

you may ruin a couple of motors trying to come up with the best way but if you dont have the money to be in this hobby then maybe you should stick with electric!!!!!!! just my two cents

Click to expand...

Not only is your post hard to read it is also wrong, you don't have to ruin a couple of engines to lean about nitro, just don't try to outsmart yourself and you will be fine!

If you don't have a lot of experience you shouldn't be trying to figure out how to break in an engine, you should read the directions and follow them to the letter. All nitro engines come with break in directions that are easy to understand until you make them complicated, the heat cycle break in has very easy to understand directions until you start questioning it. Anyone that can read and understand what they are reading should be able to break in a nitro engine, it's really not that hard.

just got a savage x

i got a new savage x and was wondering if that will work for the stock MIL.:help:

it will work with any mill

And it is a great break in method........I have used it on 6 or so mills and they are all screamers..