Bladescraper

I have bought one of these babies and to put it mildly the engine runs like s**t!!! It has air leaks beyond belief! I had to get a new tank that was sucking air and now no more air bubbles entering the engine. Now I can hear the engine surging and watch air bubbles coming out of the carb inlet for fuel, spray some carb cleaner around the carb and banjo fitting and the engine dies!! This is getting rediculous. Has anyone else had these problems?
It now appears I will have to seal all the air leaks on this POS engine before I can play with my new toy!! I do not recommend any RTR machines if this is common with them!! This isnt the only problem the body didnt fit that well either. I had to ask Ofna for a bottle of oil for the foam air filter that is required but not listed on the page of needed items. I have added the shim on the head but with all the air leaks I cant see the benefit.I am really disappointed with this car so far.

GeeBee_R2

My Feedback: (1)

I just purchased one of these and I heard they are adding the shim to the engine from the factory. This buggy is for my son and I hope he is not disapointed with it. I only looked through the box and everything looks good. He wont see it until Christmas. Did you get yours running? I am willing to work with it to get it running right.

Bladescraper

I have not gotton mine running yet and it wont idle for a full tank of gas either. I am going to have to take the engine apart and seal it with gasket adhesive then try again.

MrDHEJ

My Feedback: (5)

Out of the box they will hardly run. You have to break the engine in, which can take up to 10 tanks of fuel. All is explained in the manufactures instructions.

How are you sure the tank was sucking air?

If the engine is surging, then you either have the mixtures set to lean, or your idle is to high.

Spraying carb cleaner around the carb is an automotive trick, in the case of these tiny engines it won't work. The area your spraying around is so small, that the parts of the carb cleaner you can't see, which is vapors, still enter the engine thru the carb opening. As for it dieing, it's more then likely from running to lean and the carb cleaner flames out the engine.

I should point out that carb cleaner is very aggressive, and if you do have air leaks it's probably from the carb cleaner destroying the o-rings on the carb body.

You should not have to add a head shim. Almost every engine out there runs great from the factory. The exception is someone who is proficient at tuning engines to there peak potential.

Relax, and take a break. Nitro RC vehicles take time and patients, along with mechanical knowledge. Tuning and running your new machine will take time with hard and easy lessons to follow. You also may want to ask your local hobby store for some help. Most are more then happy to help someone new to the hobby.

You also didn't mention what type of fuel you were using, that would help in diagnosis your problem.

Bladescraper

Mr. Dhej here are the answers to your questions:

Yes the instructions say how to break in the motor per instructions it says to run at least 4 tanks not ten, secondly my kit came with 2 different recommendations for break in one sheet said to start 2 turns out on main needle another sheet said 3 turns out on main needle. when I called ofna they split the difference and said 2.5 funny how that works huh? I was sure the tank was leaking air because I could watch air bubbles go from the tank thru the inlet fuel line to the carb no fancy test here I just watched the little bubbles. When I got a new tank from Nitrohouse and installed it they're were no more bubbles leading from the fuel tank to the carb! Dont think the "vapors" from the carb cleaner were penetrating the rubber gooseneck of the air filter tube! the engine ran poorly before I started looking for air leaks after the new tank install the engine still surged badly! And if you think 3 turns out is lean then you should read the instructions yourself or call ofna like I did. I suggest you call ofna or visit their webiste under the news catagory they are offering free head shims for this engine for nitro fuels in the 25-30 percent range. I added the head shim based on advise given to me by nitro house whom I beleive to be very knowledgeable about this car. I am only running 20 percent by the way. These cars are being advertised as ready to run to the general public imagine the frustration of a child receiving this as a gift and not being able to use it. Lets not forget that the back of the instructions say to not run the car without the air filter being oiled yet its ready to run? And no mention of the oil needed on the 1st page of items needed to complete this model.

MrDHEJ

My Feedback: (5)

Actully, any engine will take 10 to 20 tanks before it'll reach peak performance. That first few tanks though will lead the engine to it's life.

Yeah, OFNA's instruction can be quite crappy. It's always been like that for as long as i can remember. But as you said, they helped you out. OFNA has got to have the best customer service there is. Normally there kits and RTR's are very excelent, every now and then a lemon gets out, but that's really unavoidable. So far out of all the OFNA rtr's and kits i've sold, only 1 has had problems, and that was just some set screws missing.

I can't say for sure if it was your tank or not, but you shouldn't have just let it go because there were bubbles in the line. Was the cap fully shut? Did you submerge test it? Were the lines on alright and not split?

Vapors are just that, vapors! Unless you have a 15" goose neck on your air cleaner, i'm sure the vapors made there way inside.

If your using 20% nitro don't add the head shim. Or if you'd like to see the differance add it, then later remove it. You'll notice the differance. As long as your temps are withen reason theres no need to add the shim.

These nitro RTR's are not meant for a child, these are not toys. In the wrong hands these cars can seriously hurt someone. Not to mention it takes a fair degree of mechanical ability to maintain and run them.

Just don't get disapointed, once you get the hang of things you'll have some serious fun. Have you found anyone else around you that run also? That's where you will learn the most, so go hang out and do some bashing. BUT HAVE FUN!

dbow

My Feedback: (1)

I have raced R/C cars for several years and that statement is not correct. There are many methods for break in and one of them is to idle several tanks through before running the car.
I usually temp at around 160 to 180 when I idle tanks through my new engines. Having a good consistant idle is required in my opinion. My MT-12 will idle as long as it has fuel at about 160 or so, will go all day if ya hook it up to a gallon of fuel...lol

As for the race cars, pumping the throttle is just added security so that you wont die before the horn goes off.
If that was the case, what would you do after coming off a long straight and breaking hard...the engine would die for sure.

Based on my experience this behavior is usually caused by an air leak. Looks like he has the needles set correctly.

10 tanks of fuel?
Most engines come from the factory ready to start up, yes you need to run a couple of break in tanks just to mate the parts. Of course its all in opinion so if some want to run 10 tanks to feel comfortable then thats great I guess.
I run 2 tanks then toss it on the asphalt and start leaning it out. My last MT-12 had 4 gallons through it and put up a 65PSI on my compression gauge when I sold it. I think it was like 70PSI brand new...just my experience



Bladescraper:
You might want to take the car to the local hobby shop and have someone look at it before you start taking it apart and adding sealant and so forth.
Once you take it apart and goo it all up, I doubt OFNA will do anything to help ya.
If ya have to do it, you want to use a selant that is fuel safe and wont be effected by the nitro (auto parts store).
The oil filter can be oiled with any regular type oil, they do make oil specifically for the purpose but its not required. Unless you run on extremely dirty surfaces I would not worry much about the type of oil, just use something.

Also, these cars are not difficult to build and maintain, its really quite easy once you get the hang of it. Most people do initially need someone to show them the path though.


Good luck and let us know of your progress.


Dbow

MrDHEJ

My Feedback: (5)

Each manufacture is differant on how to break there engines in. Some are really easy, only requiring a few tanks, and usally are an economy engine. But race engines are a totally differant beast. Take for an example a $400 race engine from RB Concepts. 1 tank idle, richen 1 turn then run 3 tanks, lean 1/4 run 3 tanks, lean 1/4 run 3 tanks. Now slowly with the next 3 tanks adjust for near peak power. This engine took 13 tanks as recomened by RB, At around 20 tanks this engine just screamed. But then again it's a differant beast.

But i'll say it again, EVERY manufacture is differant, and everyone has there opinions. With over 25 engines being broken in, the RB method works for me.

kyokai2

I dont know where that person gets his information concerning ofna customer service but I can tell you from my experience with them and they totally suck!!! As for you engine, go to your local hobby shop and get the actual air seal product they sell and seal up your carb, the banjo fitting and the back plate. If you have a pull start,which Im pretty sure you do there is an air leak that you cant fix except taking it off. Check your fuel lines very carefully and make sure they arent kinked or picnhed off. Surging is usually caused by a lean condition, either by the needle settings or restricted fuel flow so try richening it up on the bottom and top and try again and use some blue thunder 20 % fuel, it is top quality. Could be your plug also, it can cause all types of different problems, it can also make the engine run to hot as most force engines do, about 300 running rich. Remeber that you get what you pay for so If you buy a cheap RC car that is what you get. Good luck and dont give up on the engine, you will figure out what the problem is with some positive thought.

dukeduke

What motor did you have with the car? I bought the car with the OFNA 25 motor and it was a piece of junk. I've had about 6 Nitro 21 cars now and this is the first RTR that I bought. I must say that the OFNA 25 is a piece of junk. I think the Hyper 21 motors are much better.

Good luck...I think you are better off changing the motor than wasting your time with the OFNA Motor. BTW, the customer service also sucks!


Doug

MrDHEJ

My Feedback: (5)

Duke, I'm curious as to how OFNA's customer service sucked for you?

ugbandtulsa

WhOA!

I can't believe all the probs you guys were having with that RTR....man, i bought a Gtlx a year ago, and i cannot destroy that motor, it runs better than my lawnmower (and it's a toro). I finally had to just buy a hyper .21 8 port cuz I like the purple head better! I still have that force .21 as a backup. Fellas, it's all about the break in....You didn't say if your car was new, or used. Or how much experience you have with nitro. I would venture to say that at least 2 out of 3 people cannot force themselves to break the motor in properly. Here's what you do, and it will be OK. If you don't, you will stretch the crank or worse, burn the piston. Please READ this!!

I opened the box, put some (FRESH) 20% in, and used a leaf blower to cool the head (Sounds ridiculous but...wow does it work great...Heat is the enemy during break in). Also, remember to shake the fuel nicely as nitro will settle due to a higher specific gravity than the rest of the fuel. DO THIS-- I ran 3 tanks through at idle, with a 10 minute cycle. I know ofna recommends 3, but with a 100 mph wind over the head it doesn't even get warm. Run it blubbery rich, it should coat the garage floor with oil as it runs. It should start nicely with the factory settings. Do not worry about these now anyway, just get it to idle. Make sure you have a NEW plug, with a good charge in the starter. Since it's just a 2 needle carb, it's hard to lose here. No midrange, just a top and low speed. After the 3 tanks at idle, putt it around at idle on the ground for 3 more tanks, then slowly lean the hell out of it an your're good to go. The mixture is right when it blows a nice blue puff of smoke under full acceleration. You should hear a crisp zing when the car goes by under full power, not a stuttery sound.

Don't worry, you cannot destroy this force .21 motor unless you get really stupid with the needle. It is an incredibly good motor. MUCH better at 120 bucks than even the old $400 PARIS motors used to be 10 years ago (please re-read what I just wrote carefully). It may try to lean itself out a bit as it gets hot. Just remember to tune it under a warm condition, not during the first 2 minutes of driving. You need to warm the motor up first, BEFORE you put a race tune on it.

VERY IMPORTANT--Do NOT under any circumstances nail the throttle before at least 6 tanks have gone through that motor. It will run beautifully after that. As for a leaky tank....it is normal to see bubbles in the tank...that's because of the vibration and pressurization. Sounds to me like your needle settings are just way off. Make sure you have a new plug in there....ofna or I like the OS # 5.....The motor is the easy part of the GTLX...The cheap metal gears are a different story Get ready to replace the spur and the bevel gears....you will. Also, you MUST disassemble the chassis and use some red loc tite on everything metal to metal...a nitro buggy WILL shake itself apart. Good LUCK!

slodsm

My Feedback: (1)

Ok, you have gotten some great advice here man, except for one thing and this contradicts everything all the other guys have told you. You can take it or leave it but I will explain. DO NOT let your motor sit there and idle all day at less than 200 degrees while you are breaking it in. Heat is the enemy yes but so is cold. Under two hundred degrees, the brass sleeve is not expanding at the same rate as the piston and it is causing the piston to wear prematurely. Then later on when you lean it out and it does expand like it should, there will be immediate compression loss and you will never see the full performance of the motor. You can take it or leave it but I have ran so many nitro motors I can't even remember them all and that is the best advice I can give you. Don't let it get too cold or too hot. Good temps for a big block are between 200 and 260. Some will actually run better a little hotter and that is ok as well as long and you can still see the trail of blue smoke that means the engine is still getting plenty of lube. That is the main thing that will kill them in the temps. Lack of lube from being to lean. Hope you get he figured out man.

dbow

My Feedback: (1)

Well we see that break in opinions are like you know what...Everyone has one thats a little different....lol

Um, I will go ahead and state again that the point of break in which is fact by the way is simply to mate the parts, I think we all agree on that.
Does idle break in temps under 200 degress hurt your motor. It certainly does not. Break in does not begin and finish at the idle throttle level. The point is to gradually mate the parts by heating and cooling. Heating or cooling to extremes right off the bat could possibly hinder the life of the engine.
A couple of tanks at idle around 160 or 180 is a good place to start, once your motor drinks what you think is the right number of tanks at idle is when you begin to run the car. This furthers the break in process by increasing and decreasing the temps that the motor is exposed to, further mating the parts at the higher temps.

This is exactly why just about any engine manuf. suggest to slowly lean out the engine until reaching the effective zone for the motor. I think we can all agree on that.

To close, the slight differences in break break in methods really dont amount to much in my opinion. As long as you follow the general routine I dont think it matters that much.
Will anyone notice or observe a serious decrease in the life of the engine?
I seriously doubt it.


Dbow

shandman

ok guys, its hard for me to tell what is the best way to break in a motor. everyone seems very knowledgable, but i dont know who to believe. is there anything you can agree on that i can reference? i want to buy a ultra GTLX pro, but i dont want problems. what should i do? thanks

RcFlyer06

My Feedback: (4)

Well People looking for or having troubles with your gt lx pro. I'd say just be as careful as possible. It's an extremely nice car but with out taking care of it can have many problems. So far I've only this to say....Careful when driving on the street, I've already destroyed the bevel gears in the differential and the car is currently sitting in it's box with it's equipment waiting for new parts. Also.....when you first get it be patient with getting it started! IT TOOK ME THREE BLASTED DAYS TO START IT! Now it's probably because I'm a bit of a retard and didn't check the batteries but even with new ones it took forever to start up. For you new ppl out there.....EXTREME CAUTION! The engine is going to be extremely tight until you break it in. Use after run engine oil to keep it nice and lubricated during storage. You can't hurt by running the engine by running it too rich but it can be damaged by running too lean. Hopeguly this helps any one who needs it. Contact me and I'll be happy to help with what ever i can!