Hello

I'm after a OS SF 61 for my vintage pattern plane.

So far I have found an ABC for sale, although I would rather have a ringed one.

Is it worth trying the ABC? Or should I just wait until a ringed one turns up?

Could I get a new liner piston and ring, if the ABC one turns bad?

No need to start a war over the benefits of ABC over ringed!

Any advice much appreciated.

Rodders

IF you treat either engine with care..... they will last. Performance wise there is little difference in RPM when fully broken in and tuned correctly. As far as parts goes for either one...... they are hard to find depending what needs to be replaced. The exception being a new ring for the ringed engines.

Hi Rodders.....
Probably a ROSSI or NovaRossi would be better considering everything.

I have several .61 SF, and the parts are getting harder and harder to find. Rings and bearings are plentiful, but to replace a sleeve, piston, rod, crank or a case are next to impossible find. And if you did find them the cost would be more than a new engine. The SF swings a large prop and preferrs a RPM in the 11 K area.

I would recommend a new engine like the Jett, Navorossi, YS or even Evolution .61 NX.

It would depend on the type of pattern plane you are looking to build or have.

Frank

Right Frank......
Like this one.
I have not run it yet but when I do you'll probably be able to hear it.
For the record....the model number of this engine is 206R61

Thanks everyone,
I think I have heard enough to give me the info I need .

I'm going to wait until I get some serious cash and get a novarossi or even a new Rossi as the main engine.

I have seen a OS copy (ASP) with a 2 year warranty for the same price as the used OS. I might just give one of those a go.


There's not much info on them, but i found a German model shop selling the new Rossi motors (purple castings) Wow, they look the business. As someone's said its got to be a Rossi or novarossi.

Thanks for your advice

Rodders

Dave, that is exactly the same engine I have on a pylon racer. It's a real powerhouse. I have a Mac's muffled pipe on it and a Picco 12mm carb. It's set up to run 20% nitro and swings an APC 11X11 at 13,500 on the ground. I did raise the exhaust port .040. I was amazed the the inctrase in timing and the big carb really did not take much away from the idle and transition.

I had Sak trade the large carb for the smaller one due to concern over fuel draw.
Since then I've noticed several posts by you and others claiming to have good draw with the large carb w/o pump.
Back In 85' I had a couple of the 2 piece case ROSSI's with the small carb and they ran unbelieveably well with the small carb on 5% fuel.
At first I thought this one was a LS but after measuting the internals it turned out to be a SS.
I think this one is the last of them.....I tried to get another one and Sak said they were unavailable.
The pipe looks like a ROSSI 'marine' pipe....should be loud as hell.

the latest rear exhaust novarossi .61 is listed here http://www.planethobby.com/home.php?cat=29 229$ a very good value

Hello
Have you seen the cesare Rossi line of engines?

Rodders

cesare rossi engines are the novarossi/rex line of engines

O.S. .65 AX.

Problem solved.

-Robert

How little oil or many flights does it take to wear out an OS ABC liner?
I've 1000 flights on a VF and 22 gallons through an AX and I'm running the heck out of an FSR. Is it a luck thing because mine have been very reliable.
Chris...

About 10 years ago I bought a .61SF ABC from a friend that thought he needed to replace it. He has since worn out TWO .61FX's, while the SF he sold me (cheap) still runs great and still seems to make all the power it ever did. With the plug removed, there is no discernable "pinch" around TDC, but the engine doesn't seem to care. I don't fly it as often as I used to, as now I burn mostly gas and kerosene. I'll never part with it, though. It's just been too good an engine to get rid of.

Hi RCGUY59,
That pinch at TDC is supposed to be there. On ABC engines when running the cylinder and piston expand at different rates to get the tolerance needed to run those rpm's. The fact that it is still there after all of this time means you have really taken good care of it, used good fuel and haven't run it lean.

OS changed the way they applied the plating to their liners when they went to the 'RF/SF' engines. Initially, there were some serious 'peeling' problems with the ABC liners (OS never plated with chrome and I don't believe YS did either). I know I had 2 that 'peeled' with less than 50 flights (no lean runs - I thought the bearings had failed; they had, because the liner peelings ruined them) and even the big names had problems (Ivan Kristensen had to send a couple engines back). OS was really good about replacing the piston/sleeves that went bad. The later engines including the Hanno Specials (MKI and MKII) were much better, you could expect 350 to maybe 1000 flights. However, Dave Shadel started marketing true 'ABC' replacement liners/pistons (made by Henry Nelson) for the original OS 61RF which had much more aggressive porting (about 500rpm more than stock) and terrific durability. They also provided them for the Hanno with the same 'Hanno' porting; so the same power, but much better durability. For me, stock OS liners last between 350-800 flights. I had one OS 61RF-abc-p which had more than 1600 flights on the Nelson parts. There was no sign of peeling, just wear as the brass was starting to appear.
Henry Nelson is more or less retired, but when I last spoke with him (about a year ago) he still had some piston/sleeve assemblies for side and rear exhaust OS 61s.
-Will

I think the OS 61SF is an awesome engine and there are lots of them available NIB on that auction site. I collect OS 61SF-P ABC engines and they are a bit harder to find.

You can have the sleeve chromed with real chrome and then honed to match your piston. Contact a guy named Robert Oge and he can set you up. he will also chrome the crank pin which will make the engine last even longer. This guy is well known in the control line world. He also recommends upgrading the rear bearing since the stock ones do not hold up too well.

Bob Oge
15477 Owens Road
Hinkley, IL 60520
Tel: (815) 286-3969

Engine Chrome Plating

Hi Bob here, i used an os 61 fsr- abc with pump, 7-D carb, and mix control . what a great combo on my Curare ,I bult it in the mid to late 70's and still have it .Its two bad they dont still make it ,I would buy a bunch.

I just wonder how many flights Frank in Texas gets in every week to need the kind of spare parts he is running short of, ya' know? (I just pick on you Frank because you said that you are having a hard time finding parts for the SF.)
I also run an SF ABC now and it runs like the wind. I am looking forward to the same great service from it that i have been getting for all of these years from my OS engines.
Like the Super Tigre V60 that I ran in C/L Stunt for 25 years, the OS in R/C seems to be my "go to" unit.
My son just got two 46FX engines in two little CG Cap and Extra models, we'll see how it goes with these maligned engines next!
Chris... 

I have a good stash of the 61SF's, Ringed. It is hard to get rid of them, serious remorse takes place. If I croaked before my wife, she would have them on the garage sale table for .25 each
I did unload a few, could not stand the guilt, slowly replaced them.

Crank

Vince,

I wonder about that kind of thing too sometimes. I resolved to make a complete inventory of the engines I own and make a computer list with "paid for" prices. This way, when we do croak, our wives will at least be able to take a little holiday after they've been moved!

A fellow in LA wound up buying Joe Bridi's engine collection and selling them on the bay (I bought a couple). He must be close to 100K by now at least.. [X(]

David

I bought a couple of Bonner 4 channel radios from Joe before I left LA.....he mentioned at that time that he was beginning to downsize.
I'm still looking for a nice Digimite 8 channel to replace the one I bought in 65'.
It was from the first production run in late 64' and the prototype for the 6 meter frequency conversion.

My wife wants to know why I need so many motors and I told her that they don't make these anymore and it people like Crank keep buying them up !! So I have to get what I can !!!! Thanks Vin ...