Army ATC

My Feedback: (1)

Hi everyone! Inormally don't post anything bad about a certain product but I have had it with O.S. I bought a brand new O.S. 120AX from Towerhobbies. First of all, if I buy a 2 stroke motor, it's going to be an O.S. Ihave never had any problems with them until just recently. Istarted up the motor and something sounded "funny." It sounded like there was air escaping somewhere. We thought nothing about it and tried it again, the glow plug shot out like a dang bullet. Put a new plug in and the motor fired up with no problems. Next day comes around and that same sound continued. We took the plane back home and found that the head bolts were completley loose!Aren't they supposed to be tightned from the factory? I read in the manual just to make sure Iwasn't an idiot and it says nothing about tightning the head bolts. My point is, check your head bolts if you buy an O.S. motor!I almost blew up the engine from something the factory should have had done right the first time!

Flyboy Dave

My Feedback: (21)

....you must always go over a new engine and check it out
before you put it in service, no matter what the brand....

....anything assembled on a production line can have problems like this.

FBD.

scale only 4 me

My Feedback: (158)

First time for eveything I guess, I've never had a loose bolt from the factory in a Motor,, But now a days even the trusted brands are cutting corners, so ya never know

Army ATC

My Feedback: (1)

Good point here. "Even the trusted brands are cutting corners." I haven't been in the hobby that long but I have grown up around it all my life and this is the first time I have seen this ever happen. Especially with O.S. products. I couldn't believe it!

BarracudaHockey

My Feedback: (11)

I've never not gone over a motor for loose bolts before installing it in a helicopter or aircraft.

Army ATC

My Feedback: (1)

I thought that the motor was supposed to be RTFfrom the factory, other than the break in period. I could almost lift the head from the motor they were so loosely installed. It took several turns of the good ole allen wrench to get them tightned properly. That should have been done from the factory! Lesson learned.

JollyPopper

My Feedback: (6)

Sounds like another win for OSan engine that runs with zero compression.

RCKen

My Feedback: (9)

ira d

I have never had to tighten bolts on a new engine and IMO you should not have to, Yes bolts can loosen up after a few hours run time but thats a whole different
thing and somewhat normal.

scale only 4 me

My Feedback: (158)

Really? Is that why theu use torque wrenches?

Sorry Ken, but I'm calling you on that one,,
This is a very very uncommon occurrence, if it wasn't then we'd be all checking these toy engines regularly,, I've never had a loose bolt on one in my 35 years in the hobby.
I'm sure OS doesn't want everyone over tighten the bolts without a proper torque wrench right off the bat,, shoot I'd bet 99% of modelers don't even own one..

Someone just ran out the fatory quick on friday afternoon cus he/she had a hot date,, Now that "happens"

tommygun32

Every new engine I've bought (doesn't matter what brand), I take it apart and flush it out good and take a look around inside (just in case). All you need is a tiny little filing, thread, etc or whatever to go swimming around the inside of that brand new $500+ motor the first time you fire it up.....[:@]

That O.S. 120AX is worth what...$280? Ounce of prevention...pound of cure...and all that....

I never trust a 'factory' to 'get it right'. Humans are humans at the end of the day and will make mistakes.

Army ATC

My Feedback: (1)

RCKen,
I completley understand the break in procedure. If you read in my posts earlier, I think I mentioned that. If you just scanned through before posting you probably missed that. I'm just saying, if you were to buy a new car, would you check the head bolts on it? The same principal applies to this motor. O.S. should be held accountable for this problem. I have never had any problems with this before. I buy all of my motors new and most of them are O.S.'s. Never had a problem with one! I just want everyone to know to check the motor over before installing it in your plane!

Tommygun

My Feedback: (2)

Or on a smaller scale if you bought a new chainsaw or lawnmower and the head bolts came loose, you'd be on your way back to Home Depot or wherever receipt in hand demanding a replacement. And they'd happily comply. Why do we as RC product consumers have to accept less? (Besides the whole crash damage exemption thing.)

rmenke

My Feedback: (13)

Right on Tommygun:

How so spoiled we have become in our hobby, and how so little we read from the engine experts great advice. If you were running a car engine under flying conditions, you would sure keep the thing in good working order simply because your life depends on it. Keeping a engine torqued to specifications is normal maintenance. Cleaning out a engine prior to the first run should be standard to everyone. Yes, factories are getting better at this, but good they are not. I would bet that Jett and Nellson engines are very good when received because they are hand fitted, and very high quality. Frankly I put OS in the same pile with all the other junk engines. They have not been good since Fatuba bought them and started to pinch pennies, poor cheap bearings, cheep cylinder coating etc. Magazines and related advertisement speaks of quality and reliability when its not there compaired to a high quality engine. How many "great flying" ARF's have you bought that flew like crap. I understand that the shops and mag's must stay in business, but where do the guys on the net who praise poor quality come from. Ever wonder why the same guys win the club racing events, time after time, year after year? Attention to detail, careful setup and maintenance. Never a plug popping out, thats just very poor maintenance along with loose heads, backing plates and carbs. Everyone eventually lucks out and gets a exceptional engine once in a while. But the guys on top stay that way because their equipment is on top for every event.

I agree, you can tell the good from the bad just based on weather or not they own a decent torque wrench, and use it. A winner just does not "just happen". They practice, practice,practice and maintain their equipment. ENJOY

summerwind

speaking of Jett, here is a poll i ran on a choice between an OS, or Jett................tells ya something

http://www.rcuniverse.com/forum/m_9383471/tm.htm 1 to 60

and the OS in question was when OS really built great engines.
haven't seen an impressive OS in the past 3 years that would ever make me go back to OS with the exception of the multi cylinder engines.

Tommy said it best, what consumer buys any engine powered device that needs to be gone over?
same with model engines, why should a newbie have a bad day cuz he didn't spend time fixinf that brand new shiny 2 stroke he saved his hard earned money for.

the real problem with OS comes down to the distributo and how they back up the warranty..........not seen anything but BS for those who have had issues.

MetallicaJunkie

its not a big deal.... i always re torque the bolts regardless, new or used

Army ATC

My Feedback: (1)

Thank you.

MikeL

My Feedback: (3)

It's just another sign that OS isn't the name it used to be.  It used to be a higher-priced brand that competed on performance and quality.  Now it's a premium-priced brand that doesn't seem to compete with comparably priced alternatives.

Army ATC

My Feedback: (1)

Yep, I agree with you MikeL. Tommygun made a good point as well. I don't see how O.S. can send out a product from it's factory without the head bolts being correctly tightened. 

d_bodary

My Feedback: (85)

Let me see, The glow plug came out, which meant it might of been loose. Now this causes compression to leak past the glow plug and transfers combution heat to the cylinder head outside. Where it is not meant to be. Is it very well possible that this caused the cylinder head to expand more than normal. And in turned caused the next flight for the bolts to come loose?

Maybe?

jester_s1

It shouldn't fall to us to check bolts and assembly, but it does. It takes all of 15 minutes to check inside the engine and flush it out and then check the torque on the backplate and head bolts and glow plug. The vast majority of engines that come of any of the factories are put together right, but we are the last line of QC before the engine goes into the airplane. I'm sure the manufacturers could offer a line of engines that have been checked over and broken in from the factory, but who would pay for them?

Smart flyers do the same thing to ARFs just in case something isn't right. Most of the time they find nothing wrong and go fly. But it's those rare times that they do that makes that extra little bit of effort worthwhile.

Kweasel

My Feedback: (29)

OS may not be what it use to be, neither is anything else. The participants, overall, are also much less technically inclined than they were 30 years ago. We are making a big deal over something that consists of approximately ten parts with ten fasteners that can be dismantled and reassembled with simple hand tools, all in a few minutes.

MikeL

My Feedback: (3)

Used a YS lately?

summerwind

i'll have to remember this when i take delivery of my new Vette................let me see, torque wrench-check............assembly lube-check.................might as well get a new set of plugs too, you know, just in case i get a lean run..............[sm=spinnyeyes.gif]

ajcoholic

My Feedback: (10)

O.S. still makes one of the finest model aircraft engines available - based on all around ease of use/performance/tuning ability/reliability/etc. Are there other engines that run as well? Yes, but a lot of them are also lacking in some dept.

Guys who claim O.S. isnt as good as it used to be - give me a break. I have owned and run 30 to 40 O.S. engines in my now 25+ years in the hobby (along with many other brands to compare to) going back to the baffled iron/steel OS MAx line, and even a few older than that.

WHat exactly are they not as good as? I think, based on all the O.S. engines I have bought, run and flown over the years that today's engines are much superior than what I was buying as a kid.

Today, I can take any off the shelf O.S. engine, break it in in less than an hour, and go flying and be rewarded with a strong running, reasonably quiet engine that runs the same, steady way EVERY time I go flying. So what more do you want for a factory made engine? Their fits are precise, parts quality second to none.

For the record, I dont have a favourite brand and I run a whole lot of other engines I like as much or more. But, they are excellent engines and that fact cannot be argued with any common sense.

I see the same bashing for all my 8 years on here, of O.S. but no one really has anything definite to say. And the ones who know do complain, what are you basing that on? How many O.S. engines have you run and how many other brands?

Anyhow, to the OP - sometimes, mechanical things get loose. I have had back plates loosen, carbs come off or throttle barrels come out in flight. I have had head bolts loosen up as well on more than one occasion and once had a whole cylinder come loose on a gasser.

If we, as modelers, run internal combustion engines, it is OUR responsibility to check that fasteners are tight, and if you cant do that you should learn. Using an Allen wrench is not a difficult thing to do. Do you not check your engine mount bolts from time to time? Or your muffler bolts? Its the same thing.

Regards,
AJC