dan rox 90

hi I'm just wondering on what the proper way of breaking this lrp z28.r spec 3 engine is. some say to do the heat cycles e.g when the engine gets to 210 degrees Fahrenheit then you cut the engine of let it cool and start it up again for four tanks. but I've only broken in one engine (ofna force 28.) and what I did was let it idle for first tank and when the engine got a bit warm I put it on the ground and drove it very slowly just a few revs. and then the second, third ,fourth and 5th I gradually picked up the speed . is that what your meant to do for this engine? or what is the best way. My lrp should arrive in the next week
cheers

p.s (I got the hair dryer on it on the first tank and put foil on it as well)

collector1231

My Feedback: (1)

Look at alishanmao (or something like that)'s video on break-in. Very clear. I don't have Youtube, so search on Youtube "redcat nitro break in". It should pop up.

Anthoop

If in doubt...follow the manual. https://www.lrp.cc/fileadmin/lrp_anl...tee-080922.pdf

dan rox 90

anyone else?

HerrSavage

Break-in(some details will vary from person to person, but the heat cylcing principle remains..)


1.) Take the glow plug out. Look down in hole, rotate flywheel to point where piston is at bottom-most position. Then, mark a notch or spot at say 12:00 on the flywheel(with a screwdriver, body reamer, whatever.. 9:00 is easier on a Savage maybe.. Just matters that you know the location of the notch on the flywheel which corresponds to the bottom position of the piston. Or, permanent marker maybe..) Then later you can just rotate it to that position and know where the piston is. During cooling the piston should always be at BDC - bottom dead center. Put the plug back in.


2.) Wrap head in alu foil, or sock. Or both. Might as well do both for starters if it's coolish out. SH engines (LRP, Losi, Dynamite Nosram, etc..) and other RTR engines (Force like the Savage X4.6 etc..) especially can be reluctant to get up to temp during break-in...


3.) Preheat engine with a cheapo hair drier to 200-225F. With the head wrapped I can get an engine to 200ish in about ten minutes with a cheapo €7 hair drier..


4.) Start engine once it's warm. See how it idles. Don't be afraid to blip it to keep it running. You want temps to get up to 200-225 for a few minutes, then shut it down, let it cool completely, then repeat. For the first tank you can let it idle with the wheels up in the air(propped on a box or something) - if temps get to that range just idling, fine. If not, I would plop it on the ground and run it in figure-8's very lightly til temps get up there. Max 1/4 throttle in slow pulls back and forth.. Once it's been at 200ish for a few minutes, shut it off. Rotate piston to BDC immediately. Leave it til it cools completely. Break-in for the first few tanks is boring.. Bring a magazine or book or yo-yo or something.. I do this cylcing of running, getting temps to 200-225, shut off and let cool completely with piston at BDC like 5-10 times with an SH or other non-high-pinch engine.. Getting it up to 200 though might not be easy.. So I usually end up having to blip the throttle a tiny bit.. Maybe even lean the HSN a tad.. Remember, it's all about the temps, and complete cool down at BDC.. This is "heat cycling"..


Once it's cooled completely after the previous cycle, preheat again, and repeat. From cycle to cycle you can extend the running time. Over the years I've become less particular about it - so that nowadays I do the first few cycles for more extended periods - like half tanks. From the third cycle, assuming temps are good, I might even do full tanks. You can do it how you want - the original OS heat cycling method was more precise - first small cycles, then slightly longer, but afaic it's just about the temps, being rich and well lubed, and getting fuel through it..


So yeah, I do that, going easyish for the first liter or two - i.e. no extended WOT bursts(probably not even anything of half-throttle for the first two liters - on a race engine anyway. For an RTR or basher engine you can probably go to town after 6-8 tanks..) After a couple liters are through, then I just floor it like I want to, making sure temps stay around 200-240... Some higher pinch engines like Go's and Alpha's might like it a bit higher..


You have to be a bit patient and somewhat cautious for the first few tanks, but in theory and principle I don't believe in babying engines.. Just heat cycle the first half gallon with temps in the right zone, then let'er rip...


As for tuning, just lean the HSN a tiny bit at a time - as in 1/12 increments til it gets more crisp. The idle gap has to be very small - like less than 1mm. As you close the idle gap the idle might go down. Counter this by slightly and gently leaning the LSN..




Extra tips for nitro would just be, don't floor it til it's like 170F or so.. That's about it really..

dan rox 90

what about if I put foil and heat the engine up with a hair dryer then start it up and let it idle for 2 mins or so giving it a few blips and then put it on the ground and go in figure 8s as no more then 1/4 and then for the rest of the 6 tanks I will gradually build up the speed, but through this process keeping the temp around 200 degrees Fahrenheit. is that method ok??

HerrSavage

Should be fine.. Go for it.

dan rox 90

ok cool

dan rox 90

how hot should the engine be running at max once the engine has broken in??

1QwkSport2.5r

It's going to vary. Your engine will run at the temperature it runs at when it's tuned properly. Engines this small are so sensitive to changes in air temp and density that one day to the next it'll run a little differently.

I say keep it under 300F and you're fine. The bearings' outer races will start to come loose at around 340F. You really have to abuse an engine pretty hard to get it that hot so if it's hot and still running, Richen it up some and have fun. It'll just quit when it's overheated.