airraptor

My Feedback: (66)

I have two OS 120AX engines and there are 5-7 more at the club. I have had to replace both bearings in my engines, and 4 of the others have too. One guy runs his engine out of fuel then uses alot of after run oil i think it is marvel oil. his bearings went before mine. his went out after about 1-1.5 gallons of fuel. My first engine went thru about 4 before one of the bearings broke and got on top of the piston and killed piston, ring, sleeve and head. Now you cant say there isnt problems but doing alittle search on the net I found many related storys. Specially in the OS 140 and 160 engines. The pattern guys would buy new 140's and before they even ran them would change the bearings. They would switch to the Boca SS bearings and would get about 300 flights out of them.

Same goes for the OS91 FS engines many of the guys only use these engines in all thier planes and have to change the bearings once a season.

So i guess my question is why do you guys use these cheaper bearings and you guys have the most expensive engines out there. This isnt a knock on you guys because I have been using OS engine since the late 80's i had two of the Hanno 60's. Wish you guys would bring those engines back.

Bax

My Feedback: (11)

With good fuel and good maintenance the bearings won't corrode. From what we've seen over the years, O.S. engines do not corrode any more than any other brand of engines. We've had experience with O.S. Engines, HP engines, SuperTigre engines (both Italian and Chinese-built versions), Irvine engines, GMS engines, and Saito engines (before we became the O.S. service center). We've never found any one brand to be worse than any other brand.

The reason people see more difficulties with bearings in O.S. engines is because there are just a lot more O.S. engines in modelers' hands than other brands.

If a good-quality fuel is used, and the engine is well-maintained, bearings will not be a problem, and will last of many years. How an engine is run will also be a big determiner of bearing life. If an engine is run hard at high RPM, or is run with a large propeller in a lot of aerobatics, especially violent aerobatics, then the bearings take more of a beating than you'd find in a scale or sport application. Many engines we've seen with bearing problems also had other difficulties, such as low-oil fuel use, foreign object ingestion, bad mixture settings, and so on. That's not to say that any particular engine hasn't had a difficulty with its bearings, but just what the great, great majority of bearing difficulties that we see are related to things other than how the engine was made or the parts used.

airraptor

My Feedback: (66)

Just from what i have seen in the last 4-6 years. we have many guys at the club. OS bearings dont last as long as some of the other engines out there. this is with different guys all with different engines and the OS one seem to need bearings earlier with the exception being the Magnums lol. the Super tiger bearings last forever. I have two 120AX's one destroyed and had to replace the bearings in my new one already. only one gallon thru it. i am trying the BOCA Ceramic ones. The SS ones seem to hold up well in the other 120's at the field. I lost one plane because of bearing failure. Maybe its just in these larger OS engines. I have many 46's that have been setting around for 8-9 years and still run very well even after we modded them. By the way the OS 120's are all stock they are set up about as good as can get timing wise.