Hey, anybody seen one of these yet ( OS 56 four stroke )?  Check out the elimination of the
crankcase venting.      



http://www.os-engines.co.jp/english/line_up/fsalpha56/index.htm

This motor has several redesigned parts.

Stan Bidowski   

Hi Stan,
I saw the 56 on the OS website several weeks ago and I noticed that it weighs about the same as a Saito 56 with muffler which was notable because
in most of my online comparisons the Os 4-stroke in a given size was heavier than the equivelent Saito engine.   Bob Zambelli is usually the guy in the know about 4-strokes so he may have some input about this engine.

It certainly, is an interesting engine but when I looked it was priced at $250.00 which is $50.00 higher than the Saito 56 and is even priced higher than the $210.00 Saito 62.  Some retailers may at some point have special deals so you could save some on the price.

I imagine that someone will give it a try and I hope they let us know their results.

                                                            Till next time,
                                                              Pat Robinson

Some will hate it, just because of the blue rocker cover.  Steve

Although I tend to stay away from the larger  4S engines - I will use .40 max - I have done quite a bit of three way comparison between ENYA, OS and SAITO.

From a raw power standpoint, the ENYAs are just plain unbelievable. I've done a lot of flying with the .46 and .53 and they just don't let up. The .53, which I compared to the Surpass .52 and SAITO .56,  pulled the 80 ounce Polaris as if it wasn't there. I would say that it's more powerful than any 2 stroke .60 I've ever seen, including piped setups.
 
The .46 is pretty close in power to an ST .60. It showed more pulling power than the Surpass .48 and SAITO .50.

Also of note - the ENYAs have two cams that can easily be re-timed for reverse running.
 
The Surpass line is a bit mellower but still delivers quite a punch. The Surpass .40 is the most powerful .40 I've ever seen - 2 or 4 stroke. I have flown the Surpass .26, .40, .48, .52 and .70. All do the intended jobs quite well. The only Surpass that a number of C/L flyers seem disappointed with is the .30. I have not used it so I cannot comment.

People have successfully replaced piped .60s with the Surpass .52 and claimed better performance and economy.

The SAITOs seem to be the most user friendly and popular for C/L flying.
I've used the .30, .40, .40A, .45, .50, .56, .72 and .91.
I will note that, as of late, I've witnessed some mechanical failures that have me a bit concerned.

To the subject at hand - the Surpass .56 will, I'm sure, find its way into a C/L bird. I'll be anxious to see how it performs.

Bob Z.

The SAITOs seem to be the most user friendly and popular for C/L flying.
I've used the .30, .40, .40A, .45, .50, .56, .72 and .91.
I will note that, as of late, I've witnessed some mechanical failures that have me a bit concerned.

The Saitos do appear to be the most friendly.  I believe they have the lowest compression ratios of all of the 4 cycle engines.

I froze a con rod to a crank on my Saito 82 once.  Stuff happens.

I do not think that Horizon would allow a lot of field failures.  Neither would Saito.

BINGO!!!

I had the exact same concern with the SAITO .40.

I have run in many 4-stroke engines, probably 50 or 60, and every one would have some sort of discharge from the breather nipple. Except for the .40 – all I saw was some blowout from the oil that I squirted in before I started it. All the others engines – OS, SAITO and ENYA gave a noticeable grayish discharge for the initial break-in and then it settled to a trickle but there was always something coming out - usually clear.

Recently, while running a high-time SAITO .40, it stopped abruptly during a perfect run.  On disassembly, here’s what I found:
      One broken tooth on the (driven) cam gear.
      The inside of the cam housing was bone dry – not a sign of lube.
                          Inspecting the gear teeth, cam surfaces and tappets, I found absolutely no sign of wear,
                          galling or metal transfer – the only failure was the tooth itself, which fractured at the root.

I replaced the cam/gear assembly, tappets (ALWAYS done with a new cam) and ring.
The engine started on the second flip and after blowing out the lube that I had put in, I saw no sign of discharge from the breather.

Now, we will just keep running the engine and let time tell.

I friend of mine had a cam drive failure on a low-time .72 but I did not see the parts.

Regarding my own assortment of 4-S engines, I have NEVER experienced a catastrophic failure.
Many, many flights.

I replaced an exhaust valve on a Surpass .48. The metal was soft,  a common problem solved in that the replacement parts are different and harder material.

I replaced ball bearings on a used Surpass .40 – they were rusty.

I had a new SAITO .30 with a bad cam or tappets. It was replaced free-of-charge.

More to come – let’s start more dialogs.

Bob Z.