Herrsavage

Here's my break-in procedure:

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.. Or, permanent marker maybe..) 9:00 on a Savage is easier to see. 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..

Guardian707

Thanks that a big help.........

Slashbasher99

iTrader: (7)

I have a LOSI LST 2 carbon fiber chassis all aluminum with extra trans and a ton of NIP part if interested call or text 864-608-1460 for pics

fyrstormer

iTrader: (1)

Marking bottom-dead-center on the flywheel is a good idea, I never thought of that. Not sure pre-heating the engine makes much difference though, because unless you pre-heat it every single time for the engine's entire lifetime, there's still going to be high wear in the vicinity of TDC eventually. I've opened my engines after break-in without pre-heating and seen the chrome/nickel plating still looking pretty close to pristine in the pinch zone, which doesn't really surprise me, because that's the area that heats up fastest when the engine is running anyway. Maybe one reason for that is, since I run on higher-nitro fuel and I have to open the engine to add a shim before break-in, I always add a couple drops of synthetic machine oil to the edge of the cylinder, so perhaps that prevents high wear during break-in.

I add a tiny amount of CPU heatsink goop between the heatsink and the cylinder head button when reassembling the engine after adding shims. I've noticed it helps prevent temperature spikes when I'm not paying super-close attention to the cylinder-head temperature when driving on varied terrain. But because of that improved heatsinking definitely put a baby sock over the heatsink if you're going to run in cold weather, even after break-in, like Herrsavage mentioned. It helps you reach full operating temperature without having to lean-out the HSN and risk under-lubricating the engine.

Herrsavage

Yeah, preheating is just what everybody says to do. For me it's a PIA, since I always have to worry about batteries for my Comp Heat preheater. To be honest, I stopped doing it - regularly - but do use the head-cover itself, because as you say it helps get the engine up to temp faster.

For break-in though - the first 5-6 tanks or so - I make a point to preheat, since the theory does sound right, that since pinch is higher on a new engine, you should preheat to reduce strain on the rod.

But yes, I have had mega tight Go engines for ex. that I never preheated, and they were fine...

fyrstormer

iTrader: (1)

I wonder, is the strain on the conrod higher during the first run when the pinch is tight but the engine barely gets above idle, or when the engine is revving full-tilt at tens of thousands of RPMs after break-in? That's not a facetious question, I honestly don't know the answer.

Micah78

Good question,but either way it needs to/ should take it. If it doesn't, something was wrong that's out of your control. My break in consists of getting the engine started, keeping it running, making sure the temp doesn't go too high, not revving high. It's that simple, and not as critical as people on the net make it out to be. Get the damn thing running, watch the temp, don't rev it out. Overheating, dirt, lean tunes kill nitro engines. Fire it up and have fun.😜

nickandluke

I just went 1/8 scale and got the Savage. in the process of converting to brushless. The new model has 4 shocks.

Guardian707

What's a good rear Exhaust for the 4.6????

chestnutjazz

iTrader: (6)

Savage is good, but emaxx is by far the best. But honestly, you're not going to be disappointed with any of them, i have them all. I think it also depends on your driving style. They each have their own feel to them.

chestnutjazz

iTrader: (6)

Please note, I did mean T Maxx...
I also really like the revo as well..

have to also say, the savage octane is what we're running in my area
this winter, but that mostly b/c we love the gas!!!

Herrsavage

Forget rear exhaust. For performance, get a normal buggy/truggy side pipe - Dynamite 053 or 086... (former for grunt, latter for top end...)

dyehard

iTrader: (13)

I would agree with Herrsavage! I have not found a rear exhaust setup that provided good power, some say they sound cool but that is it. The ERMC pipe makes awesome power, you might look into that one

fyrstormer

iTrader: (1)

The only real advantage of a rear exhaust is it doesn't spray oil fumes on the side of the vehicle.

That said, a rear exhaust could actually work really well, if the engine were situated near the front of the vehicle, and the exhaust pipe were a rear-facing end-outlet design instead of a front-facing side-outlet design. Now I kinda wonder why they don't build nitro trucks that way to begin with.

Shawner85

Just get one of those silicone extenders for the exhaust pipe so its spraying away from the truck, those things are money.