I broke my REVO according the what Traxxas recommended. I followed every inch and every word.

Well tonight, I bought a buggy and I was breaking it in tonight. Instead of breaking it in after five tanks(per Traxxas' recommendations), I just drove it minutes at a time and cut it.

After 5-10 minutes, I would run it again yet add little throttle for seconds at a time.

Tomorrow after work, I'm going to do that a little more and give it more throttle. But after that, it will be WOT(wide open throttle) city.

I've been into this hobby for over 12 years and breaking in a motor is the last thing I like to do when I have an awesome truck and I have friends that want to race.

How do you guys break in? Do you spend a lot of time doing it? Is that much time really necessary?

Thanks for the opinions guys.

I usually break in fairly close to how the manual says to do it. If there's any deviation from that, it's only to idle the first tank, or to lift the vehicle off the ground and manually rev it up as the manual states(that car didn't have an Rx crystal, but the LHS traded me the Tx crystal for a set of Tx and Rx crystals). I take as much time as is needed to get the job done properly, and I don't like to stop in the middle of a tank unless the manual says to or it is absolutely necessary(i.e. friend stuck outside in 0 degree weather and needing assistance to get back in). I've had my 4 Tec for over a week now and I still have one more tank to run through it to finish the break in procedure, but that's not doing it all at once. I do think that it's all neccesary, but maybe not exactly how the manual says to as long as the first couple of tanks are taken easy and very rich.

I think that break in is very important. You even have to break in a brand new car before you can drive it how you normally would. Break in helps to get all the pieces to where they're supposed to be(i.e. expand the piston sleeve) because the factory can't adjust for the expansion and contration of the pieces while in opperation due to temperatures in the engine. In the long run, it will also help the engine last longer.

Break in is probably the single most important thing you can do for your RC's engine, but don't forget the after run oil either.

Good topic to let experienced nitro drivers share their oppinions on the subject to help newbies to nitro get started off right.

BTW revo, I'll be breaking in my new X-Term this weekend to, so don't feel bad. Not to mention that a buddy of mine might get him a nitro this weekend, so if he does I'll be helping him break it in as well as my X-Term.

two of my friends at work bought revos last week. both of them are new to the hobby so i tried to help them as much as i could. the first guy was to excited to do a prober breakin. he let it idle for about half a tank, then took it easy for the rest of that tank. the second tank went a little harder.................then it was wot...........against my advise, mind you. the second guy watched the vid about five times, read the book, then wtched the vid again and broke his in to the letter, except that he did it in a gravel lot instead of in a paved lot.

here's the thing.......the first guy's truck runs really well, has good power, but it doesn't hold a tune real well, and when he lets off the throttle it stalls after it worms up. i'm still working on getting the tune right so that it doesn't stall but other than that it runs well.

the second guys truck, which i havn't gotten to work on yet, wont' even run unless the glow plug is being heated. he has an airplane also (which has yet to see the sky) so he has been useing the glowplug igniter from that, and as long as it is on the truck it runs but within a few second after you pull it off the engine dies. i'm assuming that he has not reset the idle since it was broken in, so maybe that will fix his prob.

so which one will be better off in the long run? i'm putting my money on the second guy even though he is having problems right now. once i get time to spend a few mins. tinkering i have a feeling that truck is going to scream.

on a side note.........i think i toasted my 2.5 last week (ran away, flipped over, and screamed to high heaven for 20 secs or so untill i got it shut down), so i will be breaking in an os .18tm in the next couple of weeks or so. i will be heat cycleing it, for a total of about two tanks of fuel, then rich for another two, then wot..................

You guys are nothing but awesome.

THANKS A LOT MYDARTSWINGER AND MAXIMUM OVERDRIVE!!!

BTW, what's your average temp. during break-in?

It sounds like the first guy has damaged his engine by not breaking it in right, to me it sounds like the engine has not got enough compression which would explain the stalling at idle and inconsistency.

The first guys engine probably won't last very long.

Personally I like to go easy for the first few tanks, making sure that the engine gets up to temperature, then shutting it down with the piston at bottom dead centre, once it has cooled I repeat this process for about 5-8 more tanks, gradually leaning it out each tank.

It is a pain in the butt, but the engine will have a better piston/sleeve fit, have better compression and more power and last much longer than running it blubberingly rich and cold during break in.

For smallblock motors I like to run them up to 260-290 during break in. Engine temperature isn't as critical as some make out, but running too cold (200 and below) will wear the engine due to the parts not expanding properly and as a result when the engine is run hotter (where it performs best) the piston/sleeve fit will not be optimum therefore the engine will never reach it's maximum potential and will not last. I have had engines that run best at 340-350! I've also temped engines at upto 420F with no loss of performance after.

psychoreve,
You're doing something similar to the "heat cycle" method. Do a search, you'll finds tons of stuff on that method. It's quick and works well.
The only important thing I see that you're not doing is getting your piston to BDC when the engine is cooling. That can make a big difference in engine longevity and performance.
Good luck and enjoy

I don't know a lot about nitro, but I just wanted to add that patience is SO important in general for this hobby. From tuning to painting to cleaning to wrenching in general, patience pays huge dividends. My my 2 cents for what they are worth!

A good break-in procedure can help extend the life of an engine. However, even the best break-in will not guarantee long life since how the engine is treated afterwards is just as important.

I've used [link=http://rbmods.net/enginetempering.php]THIS[/link] method for the last 4 mills, and it has helped. I'm no metallurgist, but I still understand some the physics in what is described there, and I believe its the best way.

Also, I've never heard of an engine that ran 'well' at temperatures over 300 F unless it had an air leak. Most engines run best at around 230-250. Sometimes the ambient conditions will dictate temps even higher. But if you experience temps over 300 without a lean bog, I'd bet you have an air leak.

jkulhanek, DaveG55, gm72, and lstRacerX, your advice is beyond awesome.

Thank you, I appreciate the input. No matter how long anyone has been in this, their is always something new to learn.

BTW, jkulhanek, I my REVO runs great at 300ish and people I race with say I'll blow my motor.

I know my engine and its potential. I agreet with you. But 420F, WHOA!!!!!!!!!!

You are the new Nascar champion; talk about really enjoying the full potential of an engine.

I have an OLD OS CV (red block head .12) that prefers to run at 300*F. Anything under that, and it may as well not be running at all! Other than that, most of my motors will run in the 230's except for mt MAch 427 which, for some strange reason, screams at about 200ish.

420*F!?! DRIVE IT LIKE YOU STOLE IT!!!!!!!!!!!!!!!!!!!!!!!

Break in... I do heat cycle exclusivley.

Not necessarily, My O.S. CV ran well over 300F for a few gallons without any loss of performance at all. It did not have any leaks and ran 110% reliable all the time , I added a hyper head and that reduced the operating temperature down to 250-260.

Any experienced engine guru will tell you to tune the engine by performance, not by temperature. And if that means over 300F, so be it, it does not hurt the engine.

As I was saying about my 412 temp, I never run engines that hot, this was just an old engine that i was playing around with.

It will not blow from running at those temps. I don't understand why people have to run their engines at a specific temperature.

Rev the ring out of that Traxxas engine, then replace it with one of the O.S. .18 CV-R/TZ/TM motors. You will love it to bits, not only are they much faster than the 2.5, they have legendary ease of tuning and run consistent all day, you will rarely ever have to tune for weather changes unless you are having massive humidity fluctuations. I myself didnt touch my O.S. CV for months yet it fired up first pull and achieved maximum RPM after a warmup. It's virtually set and forget...

Some of that will have to do with what fuel you are running. Fuels with a high content of synthetic oils will not provide as much protection at higher temps because the synthetic oils can actually break down and burn off, therefore providing little protection. Synthetic oils do, however, provide better protection at normal operating temps than castor oils since they don't leave behind the gummy goo. This is why most fuels have both.

If you believe that trying to keep an engine between 210 and 270 F is operating "at a specific temperature,' that's fine. I believe temp guns are for insurance, not as a device to tune by.

Yes, and if they have the experience of the professional that modifies my engines, they will also tell you that temps over 300 can be unhealthy to any mill. They wont tell you it will cause it to blow, but they will tell you its going to shorten the lifespan.

This is my opinion, and it is what I have learned from people who professionally modify RC engines.

Temp guns are good for indicating abnormal temperatures which might suggest too lean or rich, but some people tune their engines till they hit that 'magical' number and drive around with an untuned mill.

I do agree that running engines at 300+F may shorten their lifespan, but running them too cold is worse. If you correctly break in an engine and run it at 300+F or wherever it performs best, you should still get a good lifespan, speaking from experience.

Not only that, model aero people I have spoken with have run engines at 350F for years with no harm done.

I have found the best fuel I have ever ran is the stuff I brew myself, it has no colouring or any other crappy additives, yet costs me less than half what it does to buy.

jkulhanec, care to share your shortcake reciepe? i Love home made shortcakes... especially if i get a cleaner product and a fruitier taste.. sorry for short thread hijacking..

on to the matter at hand..

is proper breakin of a new engine important?


Is a condom important? another good question with the same answer.

ALL DEPENDS ON your EXPECTED LIFESPAN...!!!

hth
Tim

Very important
Heat cycle works best
AS for temp guide only, my GS26 run about 490F Still going hard after 60 litres of fuel