the Wasp

My Feedback: (1)

those cylinder photos show very well why the valve is leaking !
Saito as well as Horizon has a lot of integrity, so I have to wonder if you (call first) send that cylinder to Horizon if they would sell you a new one for a reduced price, make sure you tell them the Seat is not constant all the way around,, maybe they will even replace it ?, you never know .. maybe just call Horizon and tell them the problem with that Intake Seat, then send the person these photos ?? the only thing in my mind that will stop Horizon from replacing that cylinder is the fact that you are not the original owner. so just maybe they will sell you one at a reduced price, it's well worth a try !

but then you have the rod and crank to think about.


Jim

the Wasp

My Feedback: (1)

Dave, I really wanted to put my (never started) OS 70sz Heli engine in my GP 60 size ShoeString, it's drop in fit for the engine mount,, but, no mater what muffler I use on it I will have to cut up the brand new cowl a lot, so I guess I will just put the Saito 82a in it. the Saito will twist a 2 inch lager prop but the RPM will be down a bit from the OS, the 70 may give it more top end speed but it should accelerate a bit better and climb better with the Saito.

and thanks for the valve info Dave !

no Pete, I am not going to sell that smelly ol 2 stroke LOL, I only paid $115 shipped to my door

Jim

the Wasp

My Feedback: (1)

yes, the Seat is not constant, it looks to me that the cylinder or cutter may have wobbled when the Seat was cut.. I'm betting the valve leak's where the Seat is the widest, because where the Seat is widest is where the Seat is on a steeper angle, now I may be wrong there because that Seat is pretty thin on the exhaust side

good luck, at least you know what the problem really is

Jim

Glowgeek

When I got this engine it was said to have only been broken in and flown a few times. The valve lash was at .008" int and .009" exh. With the plug removed the bearings felt glass smooth and were dead quiet. So I set the lash to .002", drown the engine in Dextron ATF and spun it through by hand. All good, so I performed the Saito recommended break in, even if it didn't need it. After break in it peaked at 9250 with an apc 14x6 and never improved. Yes, I replaced the f plug, twice to make sure. I also tried two other fuels.

Now that I've torn it down I can see by the wear on the cam and lifters that the previous owner abused it. I doubt they ever rechecked the lash after breakin, if they even broke it in correctly. As a result the cam has dents on the ramps and the tappets took a good pounding as well, (that's something I have seen in all three Saitos and the two OS I have rebuilt) The severely worn edges on the tappet bottoms don't affect the overall valve lift but do affect the valve opening duration.

So now I'm looking at buying a cam, lifters and a rod at minimum, perhaps a cylinder and crank as well. Even without the scoring on the crank pin the machining looks terrible, unless the tooling marks (ridges) are intentional. I don't remember seeing tool marks (ridges) on any of the dozen or so glow engines I've rebuilt in the past, including older 56 & 62 Saitos. Are the ridges on the 82 crank pin intentional? Perhaps Horizon would help with that as well as the cylinder, who knows. I'll call them Monday.

Glowgeek

You'll have to fill me in on the castor comment, not sure what you're getting at. Most of my experience is with car engines and 2s/4s small engine repair.

The valve seat is indeed wider in some places than others on both ports. One leaks, the other doesn't. I just chalked it up to variations in combustion chamber casting thickness. I've seen that in other saitos, although not to this degree.

Hobbsy

My Feedback: (102)

Jim, would a Turbo header and 90 degree adapter help? 11x.75mm OS 70, 72a FS & FS81a TH12x1B TurboHeader with RCS11x12S Adapter. Use RCS11x.75/90 with stock muffle

This arrangement is pretty flexible.

Hobbsy

My Feedback: (102)

Geekster, I am just not a fan of castor, once you try without it you'll never go back.

Glowgeek

Ok, I was thinking you were concerned with castor collecting on the valve seat or something. I don't run excessive castor after break in, 3-4% is my comfort spot but I'm going to stop right there. No need to start another castor vs synthetic debate.

Quikturn

My Feedback: (12)

Glowgeek

Thanks, hopefully Horizon will make it right. I've heard their CS is exceptional but I've never had a need to bother them until now. I hope your 100 just needs a quick scrub with a pencil eraser!

Oh, the pics were taken with a Cannon S-95 in macro mode, no flash with a little assistance from a small flashlight.

Jesse Open

Thank you.
Well taken. We all learn a lot here. Small glow engines were the very first engines many of us started our lifelong engine journey with. That first exposure takes many different paths for so many people. Sometimes interesting to compare "notes". It is that broad experience that has drawn so many of us towards these lovable little powerplants and the satisfaction they render. We have much in common. Engines just never lose their magical appeal for many of us. True to our roots, we still find great rewards tinkering with the engines that started it all.



Hard to beat the sound of an odd-fire Saito at part throttle isn't it?
Or perhaps that 3 cyl radial? How about the old 120 fat head slugging away with a huge, almost too big prop with a straight pipe! All is good.

the Wasp

My Feedback: (1)

with setting your valve problem aside, and that I hate to tell you this, but I researched the prop and RPM numbers for you, according to Horizon's site the Saito 91 should twist a Zinger 14X6 at 9100, so with that your 82 was doing pretty good with the numbers you posted even with the leaking valve,

once in the link click on "specs"
https://www.horizonhobby.com/product...-ee-saie091sgk

Dave, I will have to look into the 90 degree adapter for the 82 in my ShoeString, I will first have to mount the engine, that means a new engine mount,, thanks !

Jim
Saito Engines: they will take a kicking and they will keep on ticking

Glowgeek

An 82 should spin an apc 14x6 at least 9600 rpm or its not making the rated 1.5 hp. The 91s is rated at 1.6 hp or 1.7 for the GK.

I don't believe all the listed numbers in the links below but on average it looks like an 82 will make at least 1.5hp

http://www.rcuniverse.com/forum/tachometer-readings-173/4536994-saito-fa-82a.html

http://www.rcuniverse.com/forum/tachometer-readings-173/2200853-52-82-4-stroke-readings.html

Hobbsy

My Feedback: (102)

McCoy 36
This one started it all when I was 14 in 1956. I still have it along with a Spitfire .049, an OK Cub .024 and a PeeWee .020.

Glowgeek

Maaaan, that is sweet!

Hobbsy

My Feedback: (102)

It was a whole $3.95 back then. Santa Claus brought it.

Jesse Open

Mine was limited success with a Jim Walker Firebaby u-control in 1957, just before Jim walker passed away. That led to a DeBolt Champ with Fox 15X in the early 1960s that I never flew but got to see fly when I sold it to a fellow who could afford a real radio. First RC flight for me was just before I got married in 1970. A Goldberg 1/2 A Falcon with Cox .049 and a Min-X (made in Detroit by a fellow in our old club) Galloping Ghost system. No, I don't have them.
The Saitos came along around 1979 and have been a staple here since then. Took a lot of heat at the field for using those "weak" engines. No regrets!

the Wasp

My Feedback: (1)

when comparing the 82 to the 91 those are very good numbers in your link, no wonder Saito dropped their 91. as I said in my other post a few days ago my 82's carb and intake is only about .40mm smaller than my 100, make's me think the 82 uses the 91 carb and intake. to add the 82 uses the same cam and same valves as the 100. makes me want to run my 82 as much as my 115

Jim

the Wasp

My Feedback: (1)

can some one please post a link for that Prop Thrust calculator,, I got some checking I want to do, a 13 and 14 inch long prop is way too long for my ShoeString, so I will do some checking on what pitch I need for an APC 12" for my 82

thanks

Jim

Hobbsy

My Feedback: (102)

A 12 x 8 MA three blade, should be perfect. These are factory balanced too.

Hobbsy

My Feedback: (102)

Lucky for us they're not so weak anymore.

Glowgeek

Here's the one I've been using Jim. So far it has proven to be very close when measuring actual thrust and rpm with my engines and props. In the link below I have entered the data for an engine making 1.4 hp with a 12x10 2 blade prop.

http://godolloairport.hu/calc/strc_eng/index.htm

The MA 12x8 3 blade that Dave posted is probably a better choice unless you like insane air speeds and long roll outs.

I always wanted a GP 60 size Shoestring, just the coolest looking Aerobat imo but by the time I could afford it they discontinued them. I saw one fly with an OS 91 at our club's fly in this year, while it lasted. The pilot won the award for the "Most Spectacular Flight" if you know what I mean. "When flying inverted, down is up and up is money"!

Rudolph Hart

You musta been thinkin about the 'movie' bad santa,thats a smelly two stroke

Geekster dave's on the money rpm wise on the ground.On 10% with a drop of castor the fa82 and 14x6 will pull just over 9000 peaked,come back three clicks on the main and you get a flyable 8800.

Started out scratch building as a kid because that's all there was in my pocket money range.When i got in to double figures i started a proper part time job which was a big mistake.Suddenly i had enough money to buy my first 2.5cc sabre diesel engine to fly my c/l plane...one good whiff of that fuel and i was gone for good.

floyd4469

My Feedback: (1)

Looking for two Saito 125 cylinders and a crankcase. Must ship to Canada. Send me a PM. Cheers Floyd

Hobbsy

My Feedback: (102)

Similar to this.

Yes sir, and using that Testor's fuel it smelled real good. I got in real trouble one time, I started it in the living room in front of the fire place which still had ashes in it from Christmas a few days before, it sucked some ashes out of the fireplace and blew them all over the living room. I later flew it on a UC profile F-86 Sabre Jet. Fun for a 14 year old.