Sigma.40

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I was just watching the NTC3 on youtube. It's pretty sweet. I was going to get a Jato 3.3 next, but now I might have to do a little research on that one. No sense in having both of them.</p>

378

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It's no contest. The NTC3 is durable, it's designed to go fast as hell on pavement, it's well supported, and it's well built in the first place. You can't say any of those things about the Jato. The only comparable TRX car is the Nitro 4-tec, but even then it's a lopsided fight. The AE motor is better designed and more reliable, it's far easier to tune, it's shaft drive so no belts to break on pebbles and twigs, and again it's far better built. Also the NTC3 is far cheaper than the N-4Tec.


The only TRX vehicle I want is a Slayer. Even then I'd have to discard the 3.3 in favor of an OS engine, likely an .18 TZ, and I'd fit the Revo's reverse capable gearbox, before I could consider it good to go.

Sigma.40

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I am definitely going to look into it. I AM interested in an on-road car as well as the Baja 5SC . After that I think I'll be done with new r/c's. I've learned my lesson. I used to have 9 but got sick of keeping them all running and maintained. I just sold my last 4 (not including my Slash and the 8ight) on Monday.

378

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Ahahaha, yeah. I stare at Tower's catalog a lot wishing I had that car...and that airboat...ooh that B25 would be nice...oh my I need that semi truck...that engine might be fun to play with.....OOH I gotta have that...nice radio...



:\ My budget didn't even allow me to get a new TC3...had to buy used...but for an on-road car that will be used for bombing around in a parking lot I can't think of a better choice than an NTC3.

Sigma.40

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Yeah, The 8ight and the Slah 4x4 were a tax return purchase. When my wife and I graduate from cosmetology school in July, my grandma is handing us each $1000. I can definitely tell you either the Baja or the on road car is getting checked off my list. Saw the Baja SC in the shop where I bought the 8ight and the Slash last friday. My mouth was hanging open drooling for like 10 minutes. Imagine the crowds you'd draw at the beach with that thing.... until you accidently run them all over .

Sigma.40

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One last question before I go to bed. When I prime the fuel, when I'm covering the exhaust and pushing down on the starter box, is the glow ignitor in or out?

lez1troubles

Out.

Shenanigans

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Awesome to hear your having success.  I know the feeling of getting the first nitro to start...good times.  That engine will continue to perform better after break in until the sleeve and piston are completely fitted to each other.  Spend a lot of time working the tune when its time....and if one day the truck just doesnt seem to run right...dont worry too much, its more than likely a tuning issue.  I was suprised when I started at how much a quarter, or an eighth of a turn on a needle would change how the engine started and ran.  Just saying before you wonder if somethings terribly wrong....work the tune first...95% of the time that will be the issue.

Grats!

378

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My protips for tuning are a bit different.

What I do when tuning is I find a nice point where the engine is reliable, performs well, is able to warm up properly, and produces blue smoke whenever I'm on the throttle. Then, I fuhghettaboutit for six months. I don't touch my carb very often at all, only twice per year to accomodate for ambient temp differences in winter and summer. I may sacrifice a few hundred RPMs on the top end and 30-45 seconds between fuel stops, but I gain the same plug-and-play simplicity the brushless guys brag about, and if you ask me that's a good tradeoff.

Sure I could get more performance if I chased that perfect tune, but at the same time I'd spend the first two tanks every session fiddling with the carb. I'm not all that interested in fiddling with the carb, if I'm honest, I just want to have fun. So I just find a happy spot and leave it alone for half the year.

Shenanigans

My Feedback: (12)

I agree....however I remember when I first started the nitro hobby, finding that "inbetween" reliable tune was difficult.  Truck wouldnt start, or bog out, or rev like crazy when I started it....and since I started on a used mill, my first assumption was the mill was crap.  Try the next day after searching and reading post after post of my symptoms....small turn here or there..and Bam, running like a kitten again.

Now I do as you do.....the least amount of needle adjustments as possible.

378

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It's harder with crappy RTR mills than it is with high quality ones. I could almost get one with the NT16 that came in my CEN MT2, but it always needed a tweak about once a month. My OS, on the other hand, seems to not care at all. I could probably find a tune that will work for me 24/7/365. It doesn't bog or sputter, it starts easily, it will idle all day long, and it doesn't generally seem to care that it's running a bit rich. I spend more time adjusting the carb in my F150 than I do the one on my TC3!

I'm not sure about Losi's engines as I've never personally owned one, but I hear they're pretty stable so OP oughtta be able to find a tune similar to mine.

Sigma.40

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When I tune it, am I tuning it richer or leaner? I understand that you can't tell me the exact setting for my car, but is there a way that you could head me in the right direction? Also, why can't I leave it on factory settings?

I just finished my third tank of idling. The next time I run it is going to be a figure 8 at varying speeds up to 1/4 throttle. The next tank will be a figure 8 at varying speeds up to 1/2 throttle. Lastly I am going to run every which way at 1/2 throttle. 2 questions. After all this, can I open her up to full throttle? And question 2, when do I need to worry about tuning?

378

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When tuning from factory settings you are leaning the engine. Less fuel = more power and better throttle response. Up to a point, anyways.

It won't warm up fast enough, it won't have any power, it won't get along with glow plugs, and it won't get very good fuel economy. Glow fuel is too expensive to waste on an engine running break-in settings after break-in.

I take it this is how the manual says to break it in. Nothing wrong with that as long as your temps are getting up.

After the last tank you listed, yes, it should be considered broken in. Feel free to go bonkers.

Same time you start going WOT with it. Once the engine is broken in your next step is to tune for performance and go bonkers. Just remember these things when tuning:

It's better to be slightly rich than lean. Remember the oil your engine depends on to stay alive is in the fuel, and if you run it lean you starve it of that oil. If you stop getting blue smoke at anywhere above quarter throttle or so you're too lean. All that oil coming out also helps cool the engine, perhaps as much as the cylinder head. Clear exhaust at idle is fine as long as it passes the pinch test and doesn't bog.

Tune for performance, not for temps. Engine temps are a function of the quality of the tune and the airflow the engine recieves while driving the car. A healthy engine in good tune with ample airflow will never overheat.



Adjust the needles in this order: High speed needle, low speed needle, idle speed screw. If you have a midrange needle for the love of god leave it alone. The reason for this is that the LSN and idle speed screw are all affected by the HSN setting. You may have a flawless low speed setting, but if you adjusted it first it's suddenly going to be way too lean when you get the HSN happy.

Remember to only make 1/8 turn adjustments. A wild swing might take you past that sweet spot and into lean.

To test your high speed mixture, make a WOT pass on smooth pavement. The engine should emit blue smoke, it should sound smooth, and it should make tons of power. It should reach max RPM. If it smokes heavily and sounds like it's struggling to rev, bring it in and lean it 1/8 of a turn. Then repeat the test. If there's no smoke and it stalls/sputters/flutters, then it's too lean. Richen it immediately.

To test your low speed mixture, idle the engine. Then, pinch the fuel line. The engine should continue to idle normally for 3-5 seconds, then rev up a bit and stall. If it revs instantly or tries to scream, you have the LSN too lean. If it takes forever to react then it's too rich. You can also test the LSN by idling for 30 seconds, then just jamming the throttle wide open. The engine should emit blue smoke while accelerating smoothly. If it does not smoke and/or tries to flutter and stall, it is too lean. If it emits copious amounts of smoke, bogs down, and potentially stalls, it is too rich.

Set your idle as low as you can get away with. You should not need to set any drag brake for the car to sit still while running, but the car should not stall or bog after idling for thirty seconds. You should be able to fit the shell without having to blip it when warmed up. ALWAYS open the throttle slightly when tightening the idle speed screw, otherwise you might damage something in the carb.



If my wall-o-text confuses you or if you want to hear what an engine should sound like with each adjustment, watch this video:

Sigma.40

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Wow, thanks. I did not expect you to go into that much detail. My temps today were between 160-204 idling. Is that OK?

Sigma.40

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The manual says to put after run oil into the carb as well as the head. However, the airfilter is held on to the carb with a REALLY small ziptie. Do I really have to snip that ziptie verytime I use afterrun oil?

378

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That's a little on the low side. 220F is right about where you want it during breakin. Anywhere from 200 to 300 is fine once it's broken in and tuned. I doubt you hurt it though.
In six years of running nitro I have never used a single drop of ARO. None of my engines show any sign of rust forming internally after sitting for a prolonged amount of time, which they were prone to do being they were in a vehicle that broke a lot. As long as you run your engine out of fuel before you store it for more than a week or so you won't have anything to worry about. The oil residue from that fuel will be more than enough to protect your engine.

Sigma.40

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I'm going to end up owing you a WHOLEgallon of glow here pretty soon!

Sigma.40

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Should I idle it for one more tank with a sock or foil over it? Or do you think that It's ready for figure 8's?

378

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I would have been driving it around gently within thirty seconds of getting it started for the first time.

Shenanigans

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You've gotten good advice from 378....agreed on idling. Ibreak in my engines driving them. Idling tanks is an older method still used by manufacturers because its safe and easy to do. Put it on the street and give it some throttle...figure 8 it at quarter throttle until you hit about 220 degrees F.....shut it down, put piston immediately at BDC...wait 15-30 minutes or so for the engine to cool...then repeat. Im sure this has been mentioned before in this thread, but I wanted to reinforce its effectiveness....ths is called Heat Cycling and is widely used and simple to do.

Go through this cycle at least 8 times or so before you start to open up the throttle to wide open...I would still remain off WOT for extended periods of time till about half a gallon or so. Irecently broke in a 454 engine in a truggy...and after a half a gallon...Istill got mechanical pinch left....and performance continues to rise with each tank so they can take awhile to fully break in.......take your time on the break in, it will benefit the engine in the long run...and follow 378's advice on tuning, and dont try to nail the tune down to an exact mix that gives peak performance....its easy to get lost on the tune after you switch up neeldes....just get it close as he sais and have fun. Once you get better at recognizing what good and bad tunes sound like...then you can play with peak performance.

Sigma.40

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378, what's your opinion on the figure 8's. Can I run 3 full tanks (1/4 throttle, 1/2 throttle and then a little faster) or do 3-5 minute intervals, shutting it down each time?

Shenanigans, it's not that I don't believe you. It's just that I am sort of getting 3 different processes ( you, 378, and the manual) and while I am sure that you are all correct, I just want to find a happy medium.

I got time though, to figure this out since I have to wait for my street tires to get here in the mail. The only dry place to run it is in the parking lot out front of my apartment. 

Oh yeah, that video really helped 378. It answered just about every question I had about tuning. Thanks.</p>

378

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What I did when I broke my OS .18 CV-RX in was I got it started, then just started driving randomly around my driveway with the shell on. I didn't beat the snot out of it but I didn't let it stay cold either. I kept an eye on my fuel level and shut it down by plugging the exhaust with about a tenth of a tank left in it. When it cooled off, I filled the tank again, gave it two pulls and it roared back to life. That engine runs great over a gallon later.


Now, it must be said that I was dropping the CV-RX into an already somewhat worn out chassis. Your chassis is also brand new, and those figure eights will help break in the axles, diffs, bearings, steering linkage and the like. You shouldn't need to pay these parts any additional attention aside from keeping them cleaned and lubricated as time goes on. Maybe fluid changes every four or five gallons, idunno.
Ask 20 different people how to break in a glow engine. Get 20 different answers.


Funnily enough the majority of those answers, while different, will involve ensuring the engine gets up to normal operating temps.
Haha, no prob. I find it helpful when trying to remotely teach someone how to tune an engine to find a video that demonstrates the same things I'm saying, mainly because it's difficult to describe what a lean engine sounds like to someone who's never run a nitro before via text.

Shenanigans

My Feedback: (12)

No worries..there are several "right" ways to do a break in...its not an exact science, and all methods center around heating up the piston and sleeve so they can expand and fit each other.....while giving little "tension" until they have a chance to complete the process.  Pick whatever you feel most comfortable with and go with it.