Flytoolow

My Feedback: (17)

I have flowen OS for 9 years. i have flowen a 91 fs for 8 of thoes years and it is now time to rebuild it. but with a little more, i can get a new 91. my question is, how do you like the satio 100 fs? its in my price range, and it bigger. is it reliable?

w8ye

My Feedback: (16)

When the Senior Pattern Association guys come to the field, almost everyone has a OS 91 of some version. There are no Saitos.

I asked one of the officers of the group and he said that the Saito had more power and was lighter, but with the OS, you can go out on the competition line, fire up the engine, fly your pattern, No messing with the needle valve.

I have both engines, I don't fiddle with the needle on the OS but as far as I'm concerned, I don't adjust the needle on the Saito much either. I'm just a sport flyer. I do not compete in pattern.

Enjoy,

Jim

DarZeelon

Adding to what Jim said, from what I see in this country, the Saito 1.00 is very popular and is definitely lighter than the OS.91FS/Surpass/II.

It also makes somewhat more power.

But from a robustness standpoint, the OS (and its clones from Sanye) is practically bullet-proof.

The Saito (well, I did not see a 1.00 fail catastrophically yet), if like some other engines from the same stable, could probably fail if allowed to over-rev just a bit. Its gear-train could shatter.

And then you have got an expensive repair, or a $280 door-stopper...

Hobbsy

My Feedback: (102)

Dar, that is one I have never seen a Saito do, not ever.

w8ye

My Feedback: (16)

I've seen Saito, OS, Magnum, And Thunder Tiger drop valves. The damage, and repair price was about the same for all. Y-S is another story. I havn't seen one drop a valve but I've seen some get very frustrating.

Saw a old OS 120 non Surpass blow the bottom end off.

Enjoy,

Jim

Hobbsy

My Feedback: (102)

Jim, I'm going to check on something in a bit, I think the YS engines have a lot of rocker arm on the valve side of rocker shaft plus their arms are very light. The longer arm on the valve side means the ramp rising rate and total lift at the cam can be less, it also makes it easier for the valve spring to deal with lifter and pushrod momentum.

DarZeelon

Dave,


There was even a thread here in RCU, about a year ago, where a Saito 1.20 (?) chewed up its cam-gear and box, as a result of what seemed to have been excessive RPM in a dive (?). This is what was diagnosed over the thread.

I have seen it happen here too, in a Saito .72.

Hobbsy

My Feedback: (102)

I just called my friend in southwestern Va. and asked him about this. He has blown the crank through the bottom of a Saito 1.80 and a cylinder off of an OS 120, he now has five Saito 180s and a couple of OS 120s but it never happened again. Both happened on their first run using 30% nitro.

w8ye

My Feedback: (16)

Speaking of Y-S engines, I have noticed the extreme rocker arm ratio. I also have noticed the forged rocker arms in the Y-S and OS engines. I just havn't been around one that failed. Yet I know the potential for trouble in the valve area if the engine over revved.

I have a friend that runs nothing but four strokes although he would rather they were running up around 11 to 12,000. There's some potential trouble.


Enjoy,

Jim

RaceCity

I have both Saito and OS. My OS's have been champions since I got my first one in the late 80's....and I still use that one too.

Hard to beat the sound or the look of a Saito, but IMO...they're (Saito) not all cut from the same cloth...especially the overbore sizes which are structurally "suspect". My .56 blew apart at less than 4K on the test stand within 3 or 4 minutes of the first start up. Nice.

No bushed rod...cam mesh set with a paper gasket...etc, etc, etc. I'd expect more in a $50 engine, let alone one costing $200 or more.

My next 4C will be an OS. So will the one after that.

'Race

Fuelman

My Feedback: (6)

Flytoolow,
I'm a Saito and Enya 4 stroke fan. Never did like the OS 4 stroke head design that on occasion would warp, especially the 120 surpass.

Enya 4 strokes are by many, including myself, about bullet-proof. About the same power as an OS, per displacement. You can still find Enya 90 four strokes around and parts are still available. You could also get one of the old 120's which is an bored and stroked 90, a bit more power in the same case. All the enyas do very well with less expensive 5% or 10% fuel too.

For the Saito's, I love them too, never had a single problem with one of mine and have about a dozen at the moment. The 100 I have as well as the 91's I have are all sweethearts with set it and forget it tune.

Regardless of what you decide, OS, Saito or even perhaps an Enya, you will not go wrong.

Rcpilot

My Feedback: (78)

I once had an OS 120 Surpass (non-pump). That thing never did run right. I should have returned it. I've never heard this thing about the head warping. I wonder now if maybe that wasn't my problem. I replaced carb parts, gaskets, tried all kinds of plugs and fuel.

It would die everytime you chopped the throttle from WFO down to idle. The only time it would stay running was if you adjusted the low end just STUPID rich where it wouldn't transition or if you set the trim tabs up and had it idleing at 4000RPM.

I eventually took a sledgehammer to it out in the garage. Got so tired of messing with it after 2 yrs and 100s of deadsticks. My bad temper just got the best of me one day--and I turned it into chunks with a 16lb sledge.[&o]

I think that I got a lemon and just didn't know it untill it was beyond returning to the factory.

I'll bet that you could buy just about any engine and get fine results from it, if you just break it in right and treat if to good fuel and the right props.

w8ye

My Feedback: (16)

Engines do vary. If you are in competition and want the best engine, buy a half dozen. Run them all. Take the best two and sell the other four as bench run only. Never flown.

Enjoy,

Jim

buzzingb

My Feedback: (2)

Most problems associated with either engine (OS or Saito) are probally related in some way to operator error. I believe the Saitos will rev with the best of engines. But why push the rpms to this range, doesn't make sense because 4strokers make their power with torque. The power to weight ratio of Saitos just can't be beatten. The Saitos seem to have more power than some of the other brands. What I like is the instant increases in rpms (its had to get this with 2strokes).

donkey doctor

Hello; That's quite a testimonial for OS, I can see where you are at. OS fealty took a hit with their FS 70 ultimate, which no one could get to run right. Then there was the FL 70, with no ring and no cam bearings. Then there was the peeling liners on the FZs.

I like Saito's, but I like OS too, but I can't ignore the trend, I'd have to say that Saito makes a better engine. I have quite a few of each (Saito and OS) and don't have any trouble with any of them. I have had Enya's and a Laser 100, and if expence wasn't an issue, I would buy Laser engines only. I imagine that I could make any of the currently available engines work just fine and last a long time too.

RaceCity

Donkey...

Don't forget that there aren't any cam bearings in a Saito either. At least on the .56...there isn't even any con rod bushings.

I kinda think to be critical of OS for making ONE 4C with a few bushed parts when Saito does it across the product line is a wee bit like the pot calling the kettle black is it not?

w8ye

My Feedback: (16)

Most of the Saito cams have a brass bushing inside.

Working on old Saito's, I havn't seen any appreciable wear at the cam bearing itself even when the lobes on the cam were in bad shape.

Enjoy,

Jim

donkey doctor

Hello; Don't forget the thrust factor on the OS design, the crank trys to push the cam sideways, that's why they needed the bearings. The Saito system doesn't stress the bushings sideways, nor does the Enya system stress teh cam bushings that way.

But as I said, I like OS, I have their surpass range covered. I prefer teh surpass to the surpass II, but they are all good.

RaceCity

I really want to like my Saito (and it does run nice...usually), but it seems that we all have spent a bit TOO MUCH time tinkering inside them, when we should be watching them whizz past while mounted in the nose of an airplane.

That is why we buy these is it not?