I'm currently breaking in a Collari .32 which I just got pinched from Os rocket. I'm a noob to breaking in mills but have been going step by step with some of the info I found on here and also some os rocket provided. My questions are, I have to put the blow dryer on the mill because the piston will get stuck which is working pretty good. It fires right up but then it runs wide open. I've adjusted the idle and it seems to not want to stay at the right idle. Is this common? Also I'm suppose to break it in for the first few idle tanks with the controller off correct? When I have it on, it seems really jittery which it didnt before.. Any more tips in general to make this a smooth and correct break in? I wanna make sure I do it right. Thanks in advance.
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Break in probs..
- Thread starter 4u2nv
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jetmechG550
RCTalk VIP
Did you return the needles to you factory settings? I'd start there and make sure your idle screw is turned out to where it is just barely open, maybe about .016". Use the heat cycle method, IB posted a nice little explanation of what it is and how to do it in the powerplant section. Did you send in just the piston and sleeve or the whole mill?
vbgagnon
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Andy don't take this the right way, but I can't tell if your joking or not.
kx250ryder
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As far as tuning, reset needles to factory, warm the car up for about a half tank of fuel, and then do the following:
Once you get the car warmed up, do some high speed passes, and keep leaning the high speed needle until you don't see any more improvement in top speed performance. This should be done with about a half tank of fuel. Then richen the needle up slightly to account for the engine running lean at the end of the tankful.
Once you have the high speed needle set, adjust the low speed needle until you get peak acceleration after the car sits at idle for 15 seconds (judging on wheelspin). One way to get this close is to drive the car around at race pace, and then bring it in and pinch (and hold) the fuel line near the carburetor until the engine dies. It should take between 3-5 seconds to die and only increase in RPMs slightly. If it takes longer to die lean the low speed needle 1 hour. If it dies in less than 3 seconds and/or doesn't increase in RPMs at all, richen the low speed needle 1 hour.
After setting the low speed needle, re-check to make sure that your high speed needle is still properly set. Often times the low speed needle being too rich will make it seem like the high speed needle is too rich, when it may actually be properly set or even too lean already. So make sure you are still getting near maximum top speed performance.
Once the high and low speed needles are set, set the car on a stand that allows all of the wheels to be off of the ground. Increase the idle setting (clockwise) as high as possible without allowing the wheels to move. If the wheels are already moving before you make any adjustments, decrease the idle (counter clockwise) until they stop moving.
The tuning advice above for the most part is a summary of this article (note that it is two pages):
http://www.rchobbies.org/cars_eng-tuning.htm
To break in:
Run the engine as normal (not rich) and just shut it down every 3 minutes of running, set the piston to bottom dead center, and allow the engine to cool to ambient air temperatures. Repeat this process for about 30-45 minutes of runtime.
EDIT: If you aren't confident in your tuning, run the engine just slightly rich (still very close to peak performance) to make sure it is getting enough lubrication. You don't want it to be overly rich or it will put strain on the engine internals, especially if it has a tight pinch.
Once you get the car warmed up, do some high speed passes, and keep leaning the high speed needle until you don't see any more improvement in top speed performance. This should be done with about a half tank of fuel. Then richen the needle up slightly to account for the engine running lean at the end of the tankful.
Once you have the high speed needle set, adjust the low speed needle until you get peak acceleration after the car sits at idle for 15 seconds (judging on wheelspin). One way to get this close is to drive the car around at race pace, and then bring it in and pinch (and hold) the fuel line near the carburetor until the engine dies. It should take between 3-5 seconds to die and only increase in RPMs slightly. If it takes longer to die lean the low speed needle 1 hour. If it dies in less than 3 seconds and/or doesn't increase in RPMs at all, richen the low speed needle 1 hour.
After setting the low speed needle, re-check to make sure that your high speed needle is still properly set. Often times the low speed needle being too rich will make it seem like the high speed needle is too rich, when it may actually be properly set or even too lean already. So make sure you are still getting near maximum top speed performance.
Once the high and low speed needles are set, set the car on a stand that allows all of the wheels to be off of the ground. Increase the idle setting (clockwise) as high as possible without allowing the wheels to move. If the wheels are already moving before you make any adjustments, decrease the idle (counter clockwise) until they stop moving.
The tuning advice above for the most part is a summary of this article (note that it is two pages):
http://www.rchobbies.org/cars_eng-tuning.htm
To break in:
Run the engine as normal (not rich) and just shut it down every 3 minutes of running, set the piston to bottom dead center, and allow the engine to cool to ambient air temperatures. Repeat this process for about 30-45 minutes of runtime.
EDIT: If you aren't confident in your tuning, run the engine just slightly rich (still very close to peak performance) to make sure it is getting enough lubrication. You don't want it to be overly rich or it will put strain on the engine internals, especially if it has a tight pinch.
Last edited:
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- #5
lol.. Thanks.. make me feel even stupider..lol.. Nah I'm not joking. I've only broke in one other mill and that was a pro. 15 so that tells you how long ago that was. The rest have been airplanes. And thats ALOT different. All my other rigs have been used.. sadly.. Oh and my LHS did my Savage S-25 mill. (Which I got a gallon and a half out of.. Go figure.vbgagnon said:
I sent in the sleeve and the piston only. Also put a new rod on.
I let it idle (blip the throttle slightly to keep it clear) til the temps hit at least 125 then start giving it longer blips to bring it to 200...watch the temps and try to keep it at 200 - 230 for 2 tanks (since it's a pinch not new)......why would you leave the radio off to do this???
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I read to leave the transmitter off. I dunno, I thought it was kinda odd as well.Plaidfish said:
Any reason why it doesn't want to keep the idle? Ill start it up and its crazy high, bring it back down to normal and it gradually goes back up.
If all needles are back to factory settings and your idle screw is set as Jet recommended then I would try to fatten the LSN a little. If you still have the same problem go through everything for an air leak. Did you change the bearings while you had it apart?
Good luck!
Good luck!
vbgagnon
RCTalk VIP
I didn't mean to insult you at all! You might be a bit lean on the low end.
If the idle is jumping around, there's an air leak somewhere. Did you seal that thing up with RTV? If not, I'd suggest sealing it up good and tight and putting some new fuel line in. Also, check the O-ring gasket on the fuel tank.
beason
Bash, Fix, Repeat..
yea I'm with Mr. wrench, if you took it apart to take the sleeve out, you may have a leak. seal it up really good first, then try again.
if the idle is dancing around then it is almost certainly an air leak
if the idle is dancing around then it is almost certainly an air leak
I'll go with air leak for my guess as well....sounds too unstable to be just a tuning issue.....replace the cooling head gasket as well if you didn't...you really supposed to do it every time you pop the head but iGET AWAY with a few times before I replace mine.....and definately seal it w/ rtv.....I do brand new mills with the stuff just to be sure....
jetmechG550
RCTalk VIP
I was going to suggest fattening up the low end a little before but didn't want you going too many directions at once. Trying too many different things is that fastest route to f-ing things up more than they already are. Also as suggested check your head shim and make sure they went on the right way and they didn't get pinched in there wrong.
Ughhh, damn noobies!:seeing_stars:
oops...did I just type that out loud?:trashed:
Ughhh, damn noobies!:seeing_stars:
oops...did I just type that out loud?:trashed:
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