Sigma.40

My Feedback: (1)

My LHS guy told me that the compression on my 8ight is too tight and that I should put it on the running starter box (without actual starting the car up) for a few minutes to help loosen it up (sort of pre-breaking it in). Does this make sense to anyone? Will this damage anything on the car? Should I have the glow plug in or out? I would REALLY appreciate help. I am starting this thing up tomorrow and am absolutely terrified that I am going to screw something up.

378

My Feedback: (4)

I wouldn't do that. Break-in has to heat the parts up to operating tolerances to work properly, which the LHS guy's technique just can't do. All you'll do using his technique is ruin your piston. These engines use a tapered sleeve which will literally squish the piston if they aren't warmed up enough. If they don't do that, they will instead just grind away at the piston, and themselves a little, until you have no compression left.

You can loosen the glow plug a quarter turn while starting it to ease the load on the starter, though. Once it's running, tighten the plug back down, then drive it around a bit and ensure the temps get to 200F. Don't jam the throttle open suddenly or anything, but do ensure it warms up enough. When you shut down, put the piston at BDC while it cools.

Sigma.40

My Feedback: (1)

Sorry, I am completely new to nitro, but what is BDC and how do I put the piston at it? What happens if it's not at BDC?

378

My Feedback: (4)

BDC is simply where the piston is at the bottom of it's travel. The easiest way I've found to put the piston there is to simply turn the flywheel. When it spins effortlessly the piston is clear of the pinch and can be left where it is. If you need a tool to turn it, you're nearing TDC and encountering the pinch in the sleeve.

As for what happens when you leave it where it stops...some engines don't care. My CV-RX didn't. Some engines do, however, and you can ruin the piston/sleeve in these engines. If yours is high enough compression to warrant loosening the plug I'd say it would prefer to be at BDC during cooldown.


Oh, and watch this video. It will show you what's going on inside the engine.

[youtube]http://www.youtube.com/watch?v=CscBSOoB5_A[/youtube]

Sigma.40

My Feedback: (1)

So if I can spin the flywheel with my finger it's good. Right now I can spin it about and inch in either direction with my finger, after that I can't. Do you think that is BDC or TDC and should I change anything up before I start it tomorrow or should I just throw it on the box and let it rip?

378

My Feedback: (4)

Finding BDC is easy. Spin it until you feel compression in both directions, then just half that distance. Bam. BDC.

As for startup, ensure your air filter is clean and oiled properly, ensure your carb is set to the proper settings(Those should be in your manual, never assume they're set properly from the factory), and ensure your glow ignitor and starter box batteries are charged. When you go to prime it, remove the pressure line from the muffler and blow into it until fuel just hits the carb, reconnect that line, trim in about 1/4 throttle, and it should fire right up.

Sigma.40

My Feedback: (1)

I charged my glow ignitor today and my starter battery yesterday. The LHS guy set my carb to what he said was the correct settings, but I will double check that in the manual. Thank you so much 378, I REALLYREALLY appreciate it. I'm coming into this blind, I'm good with electrics but I've never even SEEN a nitro run in real life. I'd like to do this without blowing the engine. So again, thank you.

378

My Feedback: (4)

Haha, well as long as you take care of it, don't run it lean and don't beat it to a pulp it will run a very long time and be quite dependable. You take care of it, it roasts tires for you!

Oh and don't hesitate to ask if something confuses you. There's still a few of us around here that run nitro and are more than willing to help.

lez1troubles

Hi Sigma, what engine is iot that your running???
Do not start it until you know that the HSN(Highs Speed Neddle) and the LSN(Low Speed Needle) are set nice and rich, which means your engine will be using lots of fuel for the run in(Break In) or you will probably end up killing the compression.
If you can give us the make of engine you are using we can help you alot more as each engine has a different setting for the needles and what glow plug your intending to use.
Normally speeking these engines can take alot of punishment but when they go bad, they really dont want to start anymore.
TDC and BDC means Top Dead Centre and Bottom Dead Centre, when you've finished driving your buggy it's best to set you piston at Bottom Dead Centre so that when it cools down the metal will shrink and you'll keep compression longer(Very Important).
There are forums here on RCU where people have asked the same question as you. You'll find them in the engine section at the bottom of the page.
You could try warming up your engine with a hair drier befor you try to start it, this does help a bit.
Your local hobby shop guy is sending you on a track to destruction as far I'm conserned so that you screw it up and have to buy a new engine, beleave me, when I started out my local hobby store did the same.
Destroyed 2 engines following there advice untill I managed to find some one also in the hobby. Helped alot. been at it now for almost 25 years and still running strong.
Good luck for tomorrow, it'll be fun and noisy (and smelly).
Try not to be scared when it fires up.
Like 378 already said, look in your owners manual for the settings and you cannt go wrong.
One last thing,chech the opening of your carb to make sure it's not open to much other wise your buggy is going to just drive away on it's own and beleave me, you cannt run that fast, I've tried.[:@]

Sigma.40

My Feedback: (1)

It's the stock Losi 350 that came on the 8ight.

Sigma.40

My Feedback: (1)

The LHS owner put the high speed needle to flush and told me not to touch the low speed needle

lez1troubles

O.K Sigma, give me ten minutes and I'll be back to you with the settings for your engine.

lez1troubles

O.K I'm back again,
Your High Speed Needle should be set at 3 turns out from closed position.
Your Low Speed Needle should be set 4 turns out from closed position.
You can find the PDF for your engine if you type "Losi 350 engine settings" into you pc, there is actually quite a bit of interesting stuff to read including the truble shooting if some thing goes wrong.
Hope this helps a bit. Have fun dude.[8D]

Shenanigans

My Feedback: (12)

I really think you need to do some more research before trying to break this engine in....As green as you appear to be, if you dont know the ins and outs of the nitro engine and maintenence, you could damage the engine before you really have a chance to enjoy it.  Just a suggestion.

378

My Feedback: (4)

He's got us. If he's confused all he needs to do is post here.

Shenanigans

My Feedback: (12)

Research refers to asking the questions/reading before he begins the break in process. Not coming here to ask once somethings already fouled up. From his posts it seems as if he's ready to have at it based on what he has learned in this thread.....Much more to nitro than what has been stated here. Just trying to give good advice based on my experience as I did the same thing and spent a miserable 2 week process trying to find answers after the fact. Ilater learned that just a few hours of research would have eliminated the need to come to a forum and ask a question after I've already screwed something up.

I probably destroyed my first engine based on this. If the OP already planned to learn more before he starts tuggin on his pullstart...then disregard. Maybe start by reading http://www.rcuniverse.com/forum/m_5517128/tm.htm

378

My Feedback: (4)

Uhh...dude...what do you think this thread is? OP was confused, wasn't sure what to do, so he asked us before ruining his engine. I'd call that research. Besides these engines aren't complex, they aren't difficult to operate and he has the manual available.

Shenanigans

My Feedback: (12)

"I am starting this thing up tomorrow and am absolutely terrified that I am going to screw something up. "

"should I change anything up before I start it tomorrow or should I just throw it on the box and let it rip? "

Exerpts from the OP's posts. This leads me to believe he's hurrying the process of running the engine. He also seems to have gotten less than great advice from his "LHS guy". Im just trying to slow this guy down a bit to save him some headaches in the near future. No, these engines are not complex, but if you are completely green it does take a bit to grab a hold of what needs to be done...not to mention what is not complex to you or me, may be a foreign language to the next guy.

Just stating opinions here "Dude", and they're based on my experiences of not so distant memories of getting my first nitro, being overly excited about running it, doing minimal research, and running into countless issues (at the time seemed catastrophic) that I learned later were miniscule and easy to fix.

378

My Feedback: (4)

And the fact that he asked those questions tells me he's not rushing the process. If he was truly rushing he would have had it on the box within 15 minutes of getting home from the hobby shop.

Shenanigans

My Feedback: (12)

I interpret the posts differently apparently.  I still recommend waiting a bit and learning a bit about nitro maintenence, and function before he tries to break in an engine.  At the very least, read through the "Nitro FAQ's" thread in the engine forum I posted above.  Hate seeing nitro beginners get frustrated and give up on it entirely because the first experience was difficult, and it IS difficult if you go into it blind.

Good luck to you

Sigma.40

My Feedback: (1)

Yes I am nervous. It is something brand new that I have not tried before. I bought the car last Friday and have been reading nonstop about this specific car since then. I also had been reading and researching nitro engines and cars for 3 weeks before that. So yeah, I may have a few last minute questions to verify things but I am ready to start it.

378

My Feedback: (4)

Just remember to be gentle on the engine during breakin. You want to get the temps up to around 200-220 degrees but you don't want to be revving it wildly or trying to do any donuts quite yet. Oh and do not run it out of fuel during breakin, it needs the oil the most when it's new.

schuttman

From my 20plus years in nitro R/C everything that 378 said is excelent advice, Just take your time and don't rush anything, like 378 said don't run it lean keep it a little on the rich side
(a little smoke out of the pipe) after you get it broke inand plan onrunning it.
Good luck.....

Sigma.40

My Feedback: (1)

I couldn't get it started. The flywheel is so tight that I can't spin it at all with my finger. When I put it on the starter box it just wears the rubber off the starter box wheel. How do I loosen it up? Also when I try to blow air into the fuel line from the exhaust it doesn't seem to do anything.

378

My Feedback: (4)

Loosen the glow plug about a quarter turn when you get ready to start it. You can also try heating the engine if you have access to a hair dryer or heat gun.

As for the priming method, it may be hard to see the fuel. I have blue fuel lines and blue fuel so if the light is low it's hard for me to tell if I've got a prime too. The other method of priming the engine involves plugging the exhaust and cranking the engine, which you can't do at the moment.