AE Racer

In one of my RCCA magazines it has a article on how to break in your engine and it reccomends heat cycling the engine during break-in by only running the engine 2-3minutes at a time and allowing it to cool between runs. Do you guys reccomend this, only two people have told me that theyve done this and everybody else seems to just run full tanks during break-in. If anybody reccomeds this, how many tanks should I heat cycle it during break-in. Id really appricate your opinions on this because I want to start break-in very soon. Sorry for asking so many questions on break-in but I want to be sure I do it right.

btw Im breaking a Sirio .12

Thanks

TRF_TG10R

i don't know if its good...but i run the whole tank..
my engine is still have lots of compression after a gallon of nitro...

Lythion

My canned response is to follow the manufacturer's instructions for breakin but I happen to know they're in Italian. Between tanks should be enough to heat cycle the motor.

AE Racer

All the direstions say is

I guess its translated from italian, well not very specific anyway. I know that Im going to get it up to 200F right away and run it around slowly on the first tank and increase speed every tank until around the 6th or 7th tank when Ill start leaning in small increasements constantly monituring the temp. I will probably hit some full throttle bursts by the 9th tank and take it on the easy side for the next few tanks before I tune for maximum performance. Im just not sure if I should heat cycle during this process.

SlobbaTech

If you have an ABC engine then the sleeve will expand before the piston will since brass and aluminum have different expansion rates. So if your engine is too cold your piston will be wearing out prematurily since it's being run through a smaller sleeve. If it's AAC then I don't know, never had one so go by manufacturers directions. I like to idle mine up to just over 200* and let it stay there for a few minutes, shut it off and let it cool down for like 30 minutes, then do it the same again and cool back down. Then will start putting around on street at that temp not getting on gas much at all. Lean it out a little on every tank, get on gas a little bit harder but not wide open for long at all, and make sure it has plenty of time to cool down completely between tanks. I'll do like 6-8 tanks on mine, if I do less the engines run hotter, not leaner, just hotter from the excess drag it has. Also the sooner the metals can expand and start to take a set and break in around that to have a better seal is good. Everyone will pretty much have a different answer on this, so use your best judgement or go by manufacturers directions if lost.

JPHRacer

The sleeve can only expand as much as the block will allow it to expand. That is the reason why the piston is impregnted with silicon, to mach the rates of the block and the sleeve. I have yet to wear out a motor running it 150-170 during the break in procedure, in fact all my motors that I personally use have at least 3.5 gal on them and they are all running without a hitch.

AE Racer

JPH, do you reccomend heat cycling? I think you port engines so you must know your stuff.

me43

how do you guys get it to idle at 200 degrees

thats almost impossible unless you lean it out alot

but who wants to lean out an engine during break-in

i always thought that when u heat cycle an engine

you idle alittle(4-5 min.) then shut it off, your temp should be around 130-150 degrees

then let it cool till it gets around 100 degrees, then start it up again, then let it sit till it gets to around 170 degrees, then turn it off wait for it to cool till 150 and so on, and so on

and you keep doing that till you hit around 200-210

then you start driving it around giving it slow incriments

then you do the regular break in proccess


BTW, heat cycling normally only last for one tank

AE Racer

Im probably going to be running it around slowly on the first tank so I dont think Ill have a problem getting it up to 200F. I dont think theres a point of heat cycling if your going to run 4 to 5 minutes at a time because when your running rich during break-in thats about how long a tank lasts.

Korey Harbke

iTrader: (13)

For break in, I just make it run as rich as possible without dieing, then idle for like 3 tanks, then putz around for 3 tanks, then start running it a bit harder each time untill I have about 10-15 tanks through it. But if your in doubt, just go with the manifacture instructions.

-Sushi Boy

me43

you make it that rich

thats way to rich if your gonna make it so you only get 5 mintute run times


it should idle for like 20-25 minutes total on the first tank

SlobbaTech

Brass and aluminum expand differently, why do you think the engine has more compression when it's at room temp than after being run or why people heat the engine up with heat gun if the piston sticks badly? Breaking it in cold will not wear your engine out, but I do feel that it can take some life away from it and isn't the better option. If engine is too cold you are pushing the piston through a smaller hole than what it was designed for. I use to break them in by running it wide open and super rich so it'd barely run, since then I've been just getting the heat cycles into them and like it better. The machining procedures and quality of parts fit is a lot better now than what it use to be, so really all you're shooting for is a good seat on the parts. I know they use the silicone in the piston to soften it up so it is easier to fabricate, I haven't heard of them using it so the piston would expand differently but could see why they would. Take that how you want to but that is just how I feel about it. Everybody will have something totally different to say about break in so don't stray too far from the manufacturers directions since they should know their engines better than someone that has just bought it or whatnot.

Old Skool

If I have to adjust the carb to make the engine run at 200F I'll just lean out the high-end a tad. I don't really touch the low-end unless I really need to. I idle one tank and then run the snot out of it, giving it as much throtlle as it can take. You'll get a sense of how much trigger to feed into it during that first gallon. I ditch the included plug after the first tank and replace it with a fresh, uncontaminated new one. I try and keep engine temps around 220-240F.

Dexter

My only advice would be when you run an engine in is atleast for the first phew tanks is to stop the car after about 3/4 of a tank because after that the engine starts to lean off, and you don't want this to happen in the initial stages of break in.

JPHRacer

I break in all my motors at the track, just due to a lack of good clean asphalt where I live, so yes I do, I run probably about a tanks worth for each pratice round untill the top the the sleeve is full polished all the way around TDC. Once the seal is around TDC is compleate then I lean it up for some HP.

Slobba Tech: I am not disagreing with you, just staing that that there are other things to think about when talking about materials. There are many ways to skin this cat. Like you said everyone thinks that they are right.


David Wert
DWR Motors