Timthetoolman1

My Feedback: (6)

Bill, my Saito 91 is acting up. It was the first engine let alone a 4 stroke that I've had on a long term basis. It has had about 3 gallons of fuel through it. When I was learning to tune it I leaned it too much and it came to an abrupt halt. I did this about 4 different occations. I just got through setting the valves on my 1.20 and thought I might as well do the 91. Now when I increase throttle it automaticly pops and comes to a sudden stop.
Is there some damage in there or could I just have the valves off. I will check the valves again and try the .0005 setting (I will use the dial guage if I can rig up a mount for it). Thanks, Tim.

William Robison

My Feedback: (3)

rangerman:

If you had set the needles with the valves really loose you could now be 'way lean, and that's usually why a Saito will pop and quit.

Open the HS needle about 1/2 to 3/4 turn and recheck the LS, adjust as needed, and tweak the HS to suit. Probably solve your problem.

I can't think of any reason why any part of the valve train would give you such a reaction, other than having them too tight.

And don't go to the 1/2 thousandth on the 91, stay at 0.002" clearance.

Bill.

William Robison

My Feedback: (3)

Jai Williams:

You are now number 96 on the list, always glad to hear from another happy Saito flier.

But aren't you ashamed for having gotten rid of some?

Haw.

Bill.

PS: Your monocoupe looks nice. First plane I did an extended knife edge in. Think it had the Warner 150 engine, not sure. wr.

Timthetoolman1

My Feedback: (6)

I checked the valves and they are loose but not as loose as the 1.20 was and it never back fired. I tached the high end and thought I had it right but the original owner, who put only 1/2 gallon through it, said he adjusted the low end a bit. Maybe it's just getting really broken in and I need to re-adjust it? I'll go back through this thread, I can't remember what we've discussed about low end and back fireing or high end...
BTW, I just got another Saito 1.20 for a Sea Fury. It has about 1/2 gallon in it and it's about 2 months old.

Timthetoolman1

My Feedback: (6)

Bill this may help too, it runs really great at low end but it's a little harder to start than my 1.20. Once started I let it warm up for about 30 seconds or more and slowly throttle it up. At 85% it starts to kind of knock. If I leave it it will back fire and quit or if I try to advance the throttle any more it will back fire.

William Robison

My Feedback: (3)

Tim:

Still sounds like the top end (HS needle) is lean. The LS could be too, but if it idles nicely and answers the throttle cleanly it wont be too far lean.

As I said, iopen the HS a bit and try it, then a bit more, etc. If it wont go to full, and it's not blubbering, just about has to be lean. You might also check the fuel hoses and ports, be sure there's not some small bits or leaks there.

Bill.

Timthetoolman1

My Feedback: (6)

Ok Bill. I thought about that after I closed my computer, it would be the high end. I'll make it more rich and check the lines while the cowl is off. It's weird that you can tell exactly where it is, a couple clicks higher on the throttle and it stops, a couple clicks lower and it's smooth again.
I have a 2 oz spinner weight on it for balance, what do you think about them? On a stunt plane I wouldn't want all of that extra weight but it's a warbird. I guess they have their Gs also. I might try moving some stuff around and get rid of it because I would hate to wear those front bearings out.

Cedarridgetom

Hello,
I have .82s in my Ultra stick 40 and decathlon, 100 in my razzle and a 180 in my funtana 90! AND the more that club members go to electric the more Saitos I'll buy!
There is no replacement for displacement.[sm=thumbup.gif]

jlkonn

My Feedback: (1)

Bill,
I'm not trying to start a flame war but I have a question.
A club member who is very tech oriented and does a lot of research...kinda a thinking man's modeler emailed me the following when I asked him about the new 125. Is there a longevity issue with the aluminum bores?
Thanks!
JLK

<<My only problem with the way Saito is handling their marketing, and product updates, is that they are all aluminum heads, no sleeves….etc. At least on the ones that started as one size, like the 1.20, and ended up as large as the 1.80. The heat will transfer out of the hemi style head well, but when you start boring and stroking them, I worry about longevity. A good sleeved 4-stroke, with good metal used in the linings, sleeves, etc is a more dependable way to go. OS has that dependability, but they lack the power. Saito has the light weights, but lacks the longevity…and in my own opinion, YS has both the power and the longevity. YS has taken the .91 and opened it up to a 1.10 which still uses top notch metals, and sleeves, and it produces more power than a Saito 1.20, at much less weight. I guess it all just depends on the type of flying you are wanting to do. Everyone has their favorites, for their own reasons.>>

out of money

count me in i have a Saito 100 in a Seagull Harrier

William Robison

My Feedback: (3)

We now have a member number 97, it's Cedarridgetom, and 98 is out of money.

Bill.

William Robison

My Feedback: (3)

JLK:

Quote:

ORIGINAL: jlkonn
Is there a longevity issue with the aluminum bores?

In a word, no.

There are many ways to make an engine cylinder, the old classic is an iron block with a ringed piston. Works great, has a long life, but it's heavy. Many of the older engines actually had iron pistons, the "Stovebolt" Chevys for example. They were tin plated to prevent problems with similar metals rubbing. Some diesels still use iron crowns and aluminum skirts on two piece pistons. Strong, but still heavy.

Air cooled aviation engines often are built with the cylinder fins turned as part of the steel cylinder, using ringed aluminum pistons. The aluminum cylinder head sometimes has an iron "Skull" cast into it, usually it's plain aluminum, and usually has internal threads to allow it to be screwed onto the top of the cylinder if it is a radial engine. Some, like the old Kinner radials, had a flange at the top of the cylinder and the head was fastened with short screws.

In an attempt to lower the weight further, some makers used a finned aluminum "Muff" pressed on the steel cylinders. This worked, but the cooling was not as good because of the joint between the steel and the aluminum - it tended to open as the aluminum expanded more than the steel. With sufficient air flow there was no problem, but they did tend to overheat if idled too long. As an example, this was a problem with the early Technopower radials.

Almost universal in our early model engines was a steel sleeve with either a ringed aluminum piston, or a piston made of "Meehanite" iron alloy with a lapped fit in the bore.

The first real change in construction was the ABC engine, using a brass sleeve in the aluminum muff, chrome plated tapered bore, with an aluminum piston. The brass expands more than the steel sleeves did heat transfer isn't a problem. And by taking advantage of the expansion, the piston fit could be controlled very nicely. But the brass was still heavier than the aluminum.

Two makers took a side track from the ABC; Thunder Tiger and OS engines started using nickel plating instead of chrome. TT has never had a problem with the ABN engines, I've only heard of one failure, caused by a bearing coming apart. Bits of bearing removed the plating. OS, on the other hand, has a lurid history of liners peeling. They seem to have it right now, shelling looks to be a thing of the past with OS. Their reputation was so badly damaged by the peeling that with the AX engines they started calling it "ABL" instead of ABN. It's still ABN even with their new name.

There were some experiments in here for running a ringed piston directly against an aluminum cylinder bore, probably the first one most of you heard of was the Chevrolet Vega engine. This engine had problems, but they were not caused by the piston/cylinder fit. The way this was made to work was a high silicon content in the aluminum. I have a Mercedes 500 AMG, 26 years old, with the same type block. At its last overhaul standard size pistons and rings went back in, wear is not a problem. There is a variation on this called "Nikasil," this is a process applied after the block is machined, it allows a less expensive alloy to be used for the block.

Chrome plated aluminum? Way back in the late 40s and early 50s, McCullough (yes, chain saw McCullough) started chrome plating directly on the aluminum cylinder bores, not just the chain saws but also the engines they built for target drones. Porsche (cars) was also working on the same thing. They both got it to work fine after some teething difficulties,

So now, using 50 year old technology, we can eliminate the steel liners that didn't cool well, and the brass liners that are heavy. What we can't do, is run a lapped piston. It has to be a ringed engine. I'm sure some have tried, but I know of none that have been successful without a ringed piston. For obvious reasons, this construction method is called AAC for Aluminum piston, Aluminum bore, Chrome plated.

This AAC is the best yet for our engines. Good heat transfer, light weight, and a bulletproof cylinder bore.

In the Saito AAC engines I have never seen a cylinder replaced due to failure of the plating. I have replaced them due to scoring from a disintegrated bearing, others due to crash damage, even one where the owner tried to lap the valves and ruined the valve seats. Plating failure? Never.

There are still other methods I've not discussed, for example Norvel has what they call "Revlite" which I think is a variation of anodizing, but I'm not sure.

And you can tell your buddy that YS uses something similar to Nikasil, but I'm not sure of their process. And OS four strokes are all ringed pistons in the easily worn steel cylinders, except the FL-70 which uses ABN in a tapered bore and no ring on the piston.

If you make it through this, congratulations. I did run on here.

Bill.

jlkonn

My Feedback: (1)

Bill,
I can't thank you enough for the education.
I am very curious by nature and really enjoy a detailed and knowledgeable reply.
I easily "made it thru" all that.
Thanks again!
JLK
Oh...and I do own a Saito 100 that flys a UCD 60.
It is nothing like the Enya 60, 120 and R120 I flew nearly 20 years ago when I got out of the hobby.
I really had trouble with them.
Lots of deadstick landing practice!
Never a problem with the Saito...well, I'm not counting running out of fuel!

William Robison

My Feedback: (3)

rangerman:

Try it richer, as you said.

Spinner weight? I've never heard any horror stories about them, if you need it to make the plane balance and fly right use it. I can't help thinking it will put higher loads on the bearings (logic, remember?) but as I said, I've never heard of any damge directly caused by using one.

Bill.

khodges

My Feedback: (1)

Bill- I had my .56 sitting on a shelf, knocked it off while moving some things around. It fell about 4 feet, landed on a carpeted floor; wouldn't you know it, but it landed right on the throttle arm and jammed the barrel sideways into the carb. No problem, it came back out with some gentle wiggling, but it broke the tiny tip off the throttle stop screw that fits in the angled slot on the barrel. Is this screw specific to each engine model, or does one size fit many? Do you know a part # offhand? Nothing was bent or scored except this one little screw; the carb barrel is still a perfect fit in the carb body, and rotates without binding, there's just nothing to keep it there, now.

I had the engine out of the plane to clean it up and adjust valves, was planning on re-mounting it today. Dang!

William Robison

My Feedback: (3)

KH:

The throttle stop is pretty much "One size fits all" in the mid block engines, it's a 2.5 mm x 0.45 mm thread. If there's enough of your original screw left you can cut a 3 mm length of it down to 1.5 mm diameter and re use it. Or just find another 2.5 mm screw long enough to cut the straight section on the end. The actual diameter of the end section isn't critical so long as it's small enough to go in the barrel slot without binding. The screw I pulled out to check has a 19 mm length, more than enough to cut a new tip on.

HTH.

Bill.

ron ron

Got my first 4s engine and it's a Saito 150! Happy so far.
Now, since it's my only saito (for now....) I have a little question. Is it normal to hear a ticking noise when the cam gear touches the rods? I hear the noise when the engine is running and when turning the prop by hand. The engine is one gallon old and running rich.
Hope I will still like the engine after I read your answers...

w8ye

My Feedback: (16)

The ticking is normal.

This caused by the difference between the cam pushing the valves open to the point where the valves are trying to push the cam. The noise is generated by the lash in the gears between the cam shaft and the crankshaft when the lash transfers to the other side of the teeth on the gears.

William Robison

My Feedback: (3)

Ron ron:

As Jim said, hearing the click when turning the engine by hand is normal. But you should not hear it with the engine running. Check the valve clearance if you are really hearing the same noise with it running. Many other sources for noise though, could be something entirely different.

Bill.

PS: You are on the list as member number 99. wr.

ron ron

Thank you for my number Mr president!

I have checked the valves and eveything is fine. It's making the noise when either one of the valves just starts to close from fully open.
This is a new engine, only one gallon (magnum 20% heli fuel). Did not exceed 4000 rpm for at least 20 minutes. Reached full throttle only at the sixth tank. Still doesn't run hot, just a little warm so you can touch it as long as you want. It starts very easily and runs fine, but I can hear the noise.

Ron

gjeffers

i was just looking around for a saito 12mm straight pipe and seemed everyone was out so i did a search and found this:

http://www.leisure-time.com/sai.htm

some of you guys have this prob but i thought it might be of use to some,(lots of saito stuff)

William Robison

My Feedback: (3)

Gary:

Whale of a listing, and not just Saito. Bet they'd get more business if there were a search function, or even better sorting.

Bill.

tailskid

My Feedback: (34)

I think they have an 'inside' line on Saito parts Noticed they are also located in Champaign Il......wonder who else resides there

Jerry

William Robison

My Feedback: (3)

Jerry:

Zip code listings:

61821 Leisure time
61822 Horizon Hobbies
61826 Tower Hobbies
61853 Omni Models

All but Omni have Champaign, Illinois as their mailing address, Omni is listed as Mahomet, Illinois. But a clerk at Omni told me they share warehouse space with Tower.

Bill.

skd11

Here is my Saito. It is mounted in a Great Planes 1/3 scale Pitts Special. I have a Perry Pump on it because the pressurized system that comes with it dosen't work very well. This engine sounds awesome and is very powerful.