exploding rear bearing in OS .65
09-27-2019, 03:26 PM
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exploding rear bearing in OS .65
I have had my .65 OS for about 2 yrs and my flying partner has had his for 1 1/2 years. We both had .61 OS's for the past 12 to 15 years. We always expected to have to replace the bearings in the .61 every three or four years. First clue is a somewhat rough feeling when rotating the prop. I still have two .61's that have been giving good service for many years. 3 weeks ago my buddy had a engine quit in flight.and after landing the prop was stuck. The rear bearing had come apart. It was missing 5 or 6 bearings that had been ground up and spread over the interior of the engine. He bought new bearings and is still trying to get the plane to fly for more that a few min. before flaming out. My engine locked up in the same manner just yesterday but it toasted my engine. The piston was stuck in the sleeve, had to pound out with dowel. The piston was scored as well as the sleeve. The piston would not go back into the sleeve. We run 15% cool power same as in the .61's. we both are very experienced in adjusting our engines so as not to run too lean or rich. We had no indication that the rear bearing was about to go. I can't imagine that this was just a coincidence. Please tell me where we went wrong. BTW we are flying APC 12x6. I have thought about buying a new OS ,65 and replacing rear bearing with a high quality type bearing.
10-02-2019, 03:34 AM
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I fly Senior Pattern association events where the OS 65AX is pretty much the standard engine. I've heard time and again that that engine eats its rear bearings like crazy, and the factory bearing will not hold up. We push our engines harder than a lot of RC pilots, and we fly them more than most sport flyers do. One guy in our group runs nearly 50 gallons of glow fuel a year through his and buys rear bearings in bulk.
The way it's been explained to me (and I could have it wrong) is that to save weight, OS made the crankcase smaller which necessitated a smaller rear bearing. My Novarossi R60F engine doesn't have this problem, which is one of several reasons I think it's a superior engine for what we do.
The advice I've gotten from the guys who really run these engines is to immediately replace the factory bearings with plain steel ones from Boca. Then when it starts feeling the least bit rough or a glow plug dies, replace them.
The way it's been explained to me (and I could have it wrong) is that to save weight, OS made the crankcase smaller which necessitated a smaller rear bearing. My Novarossi R60F engine doesn't have this problem, which is one of several reasons I think it's a superior engine for what we do.
The advice I've gotten from the guys who really run these engines is to immediately replace the factory bearings with plain steel ones from Boca. Then when it starts feeling the least bit rough or a glow plug dies, replace them.
10-16-2019, 06:04 AM
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Since you have experience with both the OS 65 and the Novarossi R60F which do you think is the better overall of the two. We have unlimited vertical with the OS 65 which we didn't with the OS 61. But we didn't have bearing issues with the OS60..We would rather not give up the power of the OS 65 in exchange for the rossi's more dependable bearings unless the power and climb were close to the same. Before I would do that I would buy a new OS 65 and do as you say and go ahead and change out the bearing to more quality ones..Thaks
10-16-2019, 02:37 PM
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I haven't run both engines on the same plane to be able to make a real comparison, but I can tell you a few things from flying with a Rossi for about 4 years now against people flying with OS engines.
My Rossi was able to pull an 8 lb Intruder though big loops with no problem using 10% fuel and the standard Rossi muffler.
The Rossi is more a torque engine than the OS. You can't make it scream with a Jett muffler and get good power. It likes bigger props which changes some of your trim decisions.
The OS is lighter, but some of that is lost when you add the Jett muffler.
Both engines are reliable and easy to tune.
Overall, I'd say the OS has a noticeable power advantage when run with the Jett muffler and tuned perfectly. But that makes it a full throttle only engine that hesitates on acceleration and gurgles in the midrange and eats its bearings due to the high RPM. I find the Rossi to be powerful enough in stock form and enjoy the finer control over my speed and instant acceleration that it gives me. Both are competitive. If I were buying one to use today, I'd honestly probably go with whichever is least expensive.
My Rossi was able to pull an 8 lb Intruder though big loops with no problem using 10% fuel and the standard Rossi muffler.
The Rossi is more a torque engine than the OS. You can't make it scream with a Jett muffler and get good power. It likes bigger props which changes some of your trim decisions.
The OS is lighter, but some of that is lost when you add the Jett muffler.
Both engines are reliable and easy to tune.
Overall, I'd say the OS has a noticeable power advantage when run with the Jett muffler and tuned perfectly. But that makes it a full throttle only engine that hesitates on acceleration and gurgles in the midrange and eats its bearings due to the high RPM. I find the Rossi to be powerful enough in stock form and enjoy the finer control over my speed and instant acceleration that it gives me. Both are competitive. If I were buying one to use today, I'd honestly probably go with whichever is least expensive.
10-16-2019, 04:56 PM
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Thanks for taking the time to reply. I probably will go with the Rossi as I am not so much into speed. The person I usually fly with is into speed and vertical performance so we may be flying different engines soon. Thanks again
10-30-2019, 01:10 PM
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I am leaning toward Rossi .60 engine. My friend put stainless steel bearings from RC bearings hoping they would last longer and not come apart when needing replacing. They were $24 dollars vs. the steel bearings from BOCA that are in the $40 dollar range. I would have thought the stainless steel would have been more expensive..
..Maybe a case of you get what you pay for.
..Maybe a case of you get what you pay for.
11-02-2019, 12:37 PM
#10
OS uses sub standard quality bearings. It’s common knowledge that if you run a modern OS, you replace the bearings early in its life with something better than the 2nds they currently use. If you’re really smart, you don’t buy an OS and find a NIB engine made in Italy second hand and you’ll notice how much longer you don’t need to mess with the engine to keep it running right. Tweak the needle once in awhile and that’s all you should need to do. Premium priced stuff should be truly premium quality. Not just premium priced.
11-03-2019, 05:41 AM
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I don't agree that OS is substandard quality. There's a good reason they've survived while many competitors have gone out of business. The bearing issue is simple enough, although I do wish they'd have decided to make that journal a little bigger to put a more robust bearing back there. It's the only design flaw in the engine as far as I can see.
11-03-2019, 06:36 AM
#12
I don't agree that OS is substandard quality. There's a good reason they've survived while many competitors have gone out of business. The bearing issue is simple enough, although I do wish they'd have decided to make that journal a little bigger to put a more robust bearing back there. It's the only design flaw in the engine as far as I can see.
Their biggest flaws: poor quality bearings and even poorer quality plating of the liner. You can keep paying their stupid prices... I’ll pass - I’ll never buy another OS. After experiencing Novarossi, Dub Jett, SuperTigre, Enya, and even K&B - I’ll pass on OS rubbish. No high quality mass produced engine brand should ever have the reputation that OS does in regard to nickel liners peeling and bearings failing. They’ve had this reputation since the FSR and SF series.
Thats a long damn time. Last edited by 1QwkSport2.5r; 11-03-2019 at 06:40 AM.
11-04-2019, 04:50 AM
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I knew the FX series had issues with liners peeling. I haven't heard about it nearly as much with the AX series. I'll agree with you that Novarossi is a top notch engine, definitely a step up from OS. Super Tigers were beasts, but a pain to tune. That's a moot point now though. I don't think of Jett as a competitor for OS given the much higher price. They are top of the line no doubt, but you can own 2 OS engines for the price of 1 Jett. It's a different type of customer.
11-04-2019, 02:26 PM
#14
I knew the FX series had issues with liners peeling. I haven't heard about it nearly as much with the AX series. I'll agree with you that Novarossi is a top notch engine, definitely a step up from OS. Super Tigers were beasts, but a pain to tune. That's a moot point now though. I don't think of Jett as a competitor for OS given the much higher price. They are top of the line no doubt, but you can own 2 OS engines for the price of 1 Jett. It's a different type of customer.
. Novarossi is on-par with price to Dub Jett - the difference between Dub Jett/Novarossi and OS - you get double the engine for the price. I call it value - the dollar is what you pay. The value is what you get.
Super Tigre a pain to tune? Only if you don’t read the instructions that tell you how to set the carburetor. Most people familiar with OS type carburetors will fail miserably tuning an ST carb. The two brands are not designed to be adjusted the same way. Only a select series of ST carbs were machined a little wonky - Pé Reviers had a write-up about how to fix this problem. But this problem was only evident on Early G2300 engines that I’m aware of.
OS knows they have a cult like following. They know they can manufacture on the edge of crap and people will still buy they’re stuff. Then when they (the end user) prematurely wear it out and are told they are at fault of the failure (liner peeling isn’t an operator error!) they need to spend $90-150 on a new piston/liner to get their $150 engine running again. So one OS AX II .46 made in China engine and a single replacement piston/liner set costs as much as a Dub Jett .46 engine that will last 10X longer than the OS and it will make 20% more power on the same fuel.
Buy an OS if you are okay with “good enough”. New bearings or piston and liner replacement in the first year of use is not “good enough” in my book. It’s closer to “rip-off”.
Now that the real Hobbico tanked, maybe Horizon will go down a better path with OS since the old Hobbico were real jewels when end users had problems - myself included. I wish I still had the emails from when I sent them a 2 gallon AX .46 (made in Japan no less) that peeled so bad there was more brass showing than nickel. Operator error/abuse was their story and they would replace the bad parts for 25% off their web store price. Yeah, okay.
Fool me once, shame on you. Fool me twice, shame on me.Last edited by 1QwkSport2.5r; 11-04-2019 at 02:33 PM.
