Starting fully cowled Saito .56

[Miotch]

Cleaned up and test ran the old Saito .56 this weekend.  Despite sitting for 18 years and my rebuilding it purely out of curiosity, it started second flip and ran like a champ.  The only plane this engine was on was a profile ship.  Which leads me to my question.  Whenever I start this engine, I always put my finger over the venturi and turn it over once or twice to suck fuel through the line (RC carb, but I've never had problems using it flying control line).  However, there is no way I'm going to be able to put my finger, or anything else, over the venturi once it's in the plane under the cowling.  And I can't tell you how many times I've taken a great-starting engine off the test stand, put it in a plane and magically turned them into the hardest-starting engines in the world.  This isn't a stunt plane, and the only tank I have that will fit the fuselage is a 2.5-oz rectangular tank that has a slanted fuel feed in the middle of the top and two vent/fill tubes angled off the top.  I did run fuel lines off the vent/fuel pipes and curved them to exit below the cowling.  Tank/engine combination ran great (and a whole lot longer than I thought 2.5 ounces would) on the stand.  But, of course, I had easy access to the venturi when starting it.  I may have put this post in the wrong category, but I tend to look at "open" forum more than the others .....

Thanks for any tips !!
-Mitch

[frank williams]

If you are running muffler pressure ..... just put your finger over the exhaust and turn over once.

[Miotch]

If you are running muffler pressure ..... just put your finger over the exhaust and turn over once.

Thanks so much !!  That makes sense.  While I wasn't going to run on muffler pressure, it would be easy to hook the vent line up to the muffler, turn it and either leave it on the muffler or take it back off after engine primed.  Thinking like that, I could even gently blow in the vent line, I guess.  Wouldn't be the first time I had the taste of fuel in my mouth. 

[Dennis Toth]

Miotch,
If you don't run the muffler pressure you can also just prime it through the muffler/header and back flip it a few times to get it ready. Other option is to close off the vent once the tank is full and shoot in some fuel from the tank. Be carefull doing either way to not over prime. Once primed flip it through several time before trying to start to avoid a hydraulic lock from too much fuel in the cylinder.

Best,    DennisT

[Miotch]

Thanks so much.  This is the easiest starting engine I've ever had (not even close) and really hoping I can keep it that way.

[Doug Moon]

Or you could get an electric starter. It's safer too. No prime needed. It will just pull in fuel and start.

[Dave Hull]

Very interested in this discussion, as to the ease of starting a larger 4-stroke. My experience is limited to helping a friend with his Saito 62(?). Kind of spooky starting it, compared to a 2-stroke. And a bit perplexing to tune, even with the Reeves mods. All on a Legacy. My job was to rebuild the front end and get everything fitted right. I haven't seen the plane at the field much since, probably because no one wants to hassle with the engine.

One thing I would mention: if the fool thing runs backwards while starting it will have very hot exhaust coming out the venturi. I would either put an extension tube in the fuse to expose the venturi to the outside, or put in some aluminum shielding to keep from burning up the inside of your plane. The one I rebuilt had charred wood adjacent to the mouth of the venturi. Of course, other guys may never get one of these temporarily running backwards...?

The Divot

[Joe Gilbert]

Mitch no worries starting engine set up for pressure spin with starter put  finger over exh for instant it will start when releasing finger heack I will start it for you. No worries my Frend  will be well.

[Dan McEntee]

   
    I flew my Score with a Saito .56 in it for several seasons, and while I'm not claiming to be "King of the Fingers" when flip starting these, I have learned enough to probably get 80% success rate. The other 20% , God only knows!!In the Score, the engine is inverted, so the venturi points up, and given that, here is what I have figured out;

  1) You can't reach the venturi to choke it, but you can cover the muffler with a finger, and flip it through a few times. This provides enough pressure to prime the engine. Hook up the battery and see if it will bump or even just start. It doesn't take much. This just takes practice with your fuel, location, etc.

   2) If it starts and runs backwards, it will barely be running and popping over. Easy to stop with your hand cupped around the spinner to stall it. A starter prevents this completely.

  3)One of the issues is that these damn things are SO much different than what you have spent a lifetime getting used to. That extra rotation between compression strokes really throws your mind off. At first it will take a lot of focus to remember where you are on it. If you get a bump, it will take two more times around, and it will most likely start. Or you can back it up against the compression stroke and back bump it to start.

  4) Go to the Walt Brownell Channel on You Tube, and find Windy's videos of the 2004 World Champs at Muncie. Find the flights where Gilbert Berringer starts his twin Saito powered model. His engines are inverted. He has a fitting in top of each cowl, when he squirts a prime, and then hand cranks that into each engine. Then he sets the props against compression on the backwards rotation, then when he's ready he hooks up the batteries, signals, and then one whack of each prop and he's off to the handle.

  5) I always have a starter at the ready. In a contest, it it doesn't light in two or three flips, I grab the starter and go.

  6) Valve clearance makes a difference. I flew mine for several seasons with easy starts and such, but then they got more difficult. Once started, the engine seemed to run normal. Then one day I just decided to check the valves, and they were both a little wide on the clearance, so I reset as per the engine instructions and easy starts came back.
 
    Four strokes are interesting. I'm not ready to sell all my Tigers yet, but I will explore it some more once I recover the Score this summer or coming fall. I have a few other engines that may find homes in some other models also.
   Type at you later,
     Dan McEntee

[Air Ministry .]

Right , Dan .

ANY 4 stroke VALVES need the correct clearance . why ! . . . .

ahem . Used to do GOOD Shiny Newish valves with the feeler guage just firm ( you can feel light drag , just ) ON THE EXHAUST ,

and ' just free ' on the Exhaust . Where you find the drag & go just past it ( opening adjuster a smidgeon . ) so the feeler guage is free . Just .

So you gain intake timing & lift , a iota . And SEE that the Ex. V WONT dwell drag stay OPEN when it oughtnt . As it need to SEAT to COOL . Or it'll Burn the
seat area through blow by - like a gas torch . 

Some play with clearances ( Full Size ) a few thou.  To Alter Characteristics of run . But ya gotta monitor it & have a fine perception of minor enhancements . 
Running 16 instead of 12 thou. Gotta Commando Snorting , on a 2S cam . WITH Hi Tech valve springs . The Seated Pressure & Shimmed for .040 ' overlft ' without
clashing , & .040 extra to piston , turning over . ( You Turn the Adjuster IN the extra . as a CHECK . ) But PROPORTIONATELY on a Satio , you DONt have a Half inch LIFT .
so youd need to SCALE the Numbers . All schoolboys knew how to grind the seats / valves - to mate . All wants to be clean . And Thats the Brief Version .     

STARTING , ere in Aus. Turning over inverted engines  BACKWARD after primng , say six times = ensures it dosnt HYDRAULIC and LOCK = bend the ROD . Flooded .
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After Run oil up the vent is essential if youre not flying regularly , and adviseable if you are . Adviseable to Pre Oil the Cam Box - That Way - Before use - daily .
So its not all dry & metal to metal , in there . As Breather flow function can vary . we're Told . Mustve been listening , apparently .

Want a big heavy short engine for my Typhoon . 18 Ounces plus .

[Dave Hull]

Thanks for clarifying these things, AirMiniseries! So, to get a “Snorting Commando” you adjust the lift with yer Tommybar, thereby getting shimmed on the deal. And all schoolboys in short pants know how to grin at the valves. (Not sure why that was important here on starting 4-stokers…but I’ll include it in my 4-S starting routine.) But since you are in the lower hemisphere where inverting the engine and flipping backwards won’t flood the engine, do the rest of us in the northern hemisphere leave it upright and flip forwards to clear the flood—even during a drought--or do we just launch inverted with bent rods?

Not quite sure about your discussion of the birds under the bonnet. Instead of making sure yer engine has a smidgeon, wouldn’t you be  better off watching out for snipes? Also, I was given to understand that the Saitos were manly engines, and didn’t need to wear no half inch lifts? Or, did I get that all bassackwards?

In the end, I think I bl##dy well understood your opinion about getting lubed up the breather…….on 4-strokes.

I dunno about the other 4-stonkin' motors, but a Reeves 62 would run backwards strong! No way I wanted to try to grab the spinner and expect to hold a fork at dinner afterwards.... And when it did run backwards, it was burnin' a hole thru the 1/2" balsa web between the engine mounts. The little .20-sized gizmo had muucch better manners....

The Divot

[Miotch]

I learned my lesson the first time I ran this Saito on a test stand 20 years ago: do not let your left hand dangle as you reach around the engine to the needle valve.  I'm lucky to still have an index finger on the left hand.  No way, no way, no way am I trying to grab a spinner on one of these, no matter how slow it is running.  I've learned the hard way on circular saws, table saws and Saito on a test stand.  Been real lucky to still have all my fingers and my right leg.

[Dan McEntee]

Thanks for clarifying these things, AirMiniseries! So, to get a “Snorting Commando” you adjust the lift with yer Tommybar, thereby getting shimmed on the deal. And all schoolboys in short pants know how to grin at the valves. (Not sure why that was important here on starting 4-stokers…but I’ll include it in my 4-S starting routine.) But since you are in the lower hemisphere where inverting the engine and flipping backwards won’t flood the engine, do the rest of us in the northern hemisphere leave it upright and flip forwards to clear the flood—even during a drought--or do we just launch inverted with bent rods?

Not quite sure about your discussion of the birds under the bonnet. Instead of making sure yer engine has a smidgeon, wouldn’t you be  better off watching out for snipes? Also, I was given to understand that the Saitos were manly engines, and didn’t need to wear no half inch lifts? Or, did I get that all bassackwards?

In the end, I think I bl##dy well understood your opinion about getting lubed up the breather…….on 4-strokes.

I dunno about the other 4-stonkin' motors, but a Reeves 62 would run backwards strong! No way I wanted to try to grab the spinner and expect to hold a fork at dinner afterwards.... And when it did run backwards, it was burnin' a hole thru the 1/2" balsa web between the engine mounts. The little .20-sized gizmo had muucch better manners....

The Divot

    Is this one of Bob Reeves personal engines? If so, I wonder if it's one that he changed out the gear in the valve train to allow left hand operation? Search around the 4 stroke section and he posted quite a bit about it. I ordered up the parts for one of mine and some left handed props, but have not done anything with them yet. Mine would act about like any other large two stroke engine that would backfire and run backwards until stopped. I've seen Fox .35s do it. It just doesn't run with any authority and did not do it all that often. I just have to wonder if you got one of his left hand engines??

  Type at you later,
   Dan McEntee

[Dave Hull]

Dano,

It wasn't my plane or engine. However, I volunteered to find some run issues it had. I found some split tubing and a leaky tank--and just kept going. Ended up rebuilding the nose to solve a number of issues and to stiffen it up. I know the owner was in communication with Bob about the carb mods. I'm not sure but the engine was probably sent to Bob. It was a reverse rotation setup. On the wing it said "powered by Reeves Otias 62" which is Saito backwards....

I can tell you that using the recommended nylon "choke screw" in the venturi works great--as long as the engine never runs backwards. If it does, it melts the screw right away and changes the run characteristics. So I shortened it to remove the damaged end and we moved on to solving its other issues. We were never quite satisfied with the run characteristics, mostly due to lack of consistency.

Bottom line for me was that I was never completely comfortable handling the engine. Just not used to the 4-stonkers.

The Divot

[Dan McEntee]

Dano,

It wasn't my plane or engine. However, I volunteered to find some run issues it had. I found some split tubing and a leaky tank--and just kept going. Ended up rebuilding the nose to solve a number of issues and to stiffen it up. I know the owner was in communication with Bob about the carb mods. I'm not sure but the engine was probably sent to Bob. It was a reverse rotation setup. On the wing it said "powered by Reeves Otias 62" which is Saito backwards....

I can tell you that using the recommended nylon "choke screw" in the venturi works great--as long as the engine never runs backwards. If it does, it melts the screw right away and changes the run characteristics. So I shortened it to remove the damaged end and we moved on to solving its other issues. We were never quite satisfied with the run characteristics, mostly due to lack of consistency.

Bottom line for me was that I was never completely comfortable handling the engine. Just not used to the 4-stonkers.

The Divot

   OK, so to make sure I understand, we are talking about a Saito set up to run counter clockwise when viewed from behind the prop. So, then when you say it runs "backwards strong"  then it is running clockwise when viewed from the cockpit? I'm gonna take a wild guess that something is not correct with the valve timing??? If I'm remembering correctly, you just need to change a gear to achieve this, but maybe if you get things a tooth off in the right spot you end up with what you have???  I will use the words "widely timed" for lack of a better description. I haven't taken any of mine apart yet, so you are one up on me. When mine runs reverse, it just barely does so. This may be a good question to log into the 4 stroke section.
  Type at you later,
    Dan McEntee

[Robert Zambelli]

A special tool is required to set the SAITO valve timing.
You might find the information on a SAITO chat site.
If not, let me know and I'll send you the info and directions.

Bob Z.

[Joe Gilbert]

Dan a four stroke saito will run backwards. Have had it happen , put finger over exh flood engine before melting Venturi.

[Air Ministry .]

This , one runs each way . But I think that may be deliberate . 

https://stunthanger.com/smf/index.php?action=dlattach;topic=25376.0;attach=104949;image

I think the D fell of Dave . GRIND - Valve seat / face . Better to just CLEAN a tiny cut if reqd. Perhaps .

CAM TIMING , any cam , almost , the OVERLAP where theyre coming off exhaust onto intake ,
WHERE thats just closing and thats just opening , happens at Top Dead Centre , just before .

SO , with the Valve Covers OFF , you can SEE if thats going on as it goes across T D C , each second turn .

3 Deg. early on the best Commando built . but thats typical .

Reading a Race Triumph THING , the blokes fine tuning the power with Valve Clearance Variations . Minute ones . a Thou. or Two .
On a liddle Satio , that'd be N'ths !  BUT theye'd Still Bias the OPERATION . as in power characteristics .

The Elite of the T 120 tuners / cam men , where endless in theyre development , Cams for specific tracks & conditions . WHICH
is where you can get it to pull  best / Come On - > due to the OPENING Varying a few degrees with a few Thou. Clearance bias !

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SO , if the Valve Clearances are out / off , the cam opening & closing timing is effectively INCORRECT .

Most Cycles you used .020 for checking TIMING , as its up the cam ramps a touch , making it more deciseive .
Another cunning way is measuring LIFT at T D C .

But thats almost ludicristly tecnical , where you can ' run it over top ' and OBSERVE the Overlap . ! ! ! it should be Just Before T D C .
Never after unless your running 5.000.000 rpms .

Both lobes on one cam your No Sweat . But a Triumph is a Twin Cam . So you can vary BOTH in relationship to each other .

[Air Ministry .]

you can see up 45 deg. to the right = Where the LIFTERS would be both near closed , but not .

that theres the OVERLAP period ! That should be At the TOP with the piston at the TOP , Ea. 720 Degree of rotation .
as obviosly the cams half speed . Unless its a two stroke . 

Havnt read it but will throw it on . ears Even .

[Dan McEntee]

Dan a four stroke saito will run backwards. Have had it happen , put finger over exh flood engine before melting Venturi.

   As I have already said, I have had mine "run backwards" but not at full tilt boogie like Dave was mentioning. It would just run low RPM until stopped, and once it a while it would backfire again and run correctly. Mine has never shown that it would run anywhere near "normal. It turns out the engine Dave was working with is set up for reverse rotation. and my guess is that there is some sort of error in valve timing. I was under the impression that one thing about 4 strokes was the ability to have the intake and exhaust timing very precise with no overlap to prevent such things. I am far from an expert on 4 stroke engines but if yours and other examples seem to run the same each way, I just have to guess that there is something not correct in the valve timing. I have witnessed two stroke motorcycle engines run backwards and give a big surprise to the rider when he cracked the throttle and dumped the clutch !!  I'll have to search through the 4 stroke section and see if there is any specific threads on the issue. Just thinking out loud here, for it to run in both directions, it has to have a fuel/air charge through the exhaust at the "wrong " time, and then the glow plug will take care of the ignition. Maybe some sort of leak in the head?? I just think that there has to be a pretty specific explanation.
 Type at you later,
  Dan McEntee

[Joe Gilbert]

Should of mentioned that mine are Bob’s set up running on pressure. Somehow the fuel goes in exh  and engine will run hard not like a two stroke running backwards  if lift alone it will melt Venturi and choke screw I have not tried to figure out why. I never let mine run backwards  long enough to tach and see how fast it was going but It was sounding like it was normal speed I put finger over exh and flooded  it quick as I could.

Regards

Joe Gilbert

[Air Ministry .]

There was some car once , that could start backward . Realiseation came on letting in the clutch . Mighta been a SAAB or Trabant 2 stroke ,I dont recall . Not a italian Tank ? .        .

[Dan McEntee]

Should of mentioned that mine are Bob’s set up running on pressure. Somehow the fuel goes in exh  and engine will run hard not like a two stroke running backwards  if lift alone it will melt Venturi and choke screw I have not tried to figure out why. I never let mine run backwards  long enough to tach and see how fast it was going but It was sounding like it was normal speed I put finger over exh and flooded  it quick as I could.

Regards

Joe Gilbert

  The .56 I have been mainly operating has the Reeves set up also. It has a UHP venturi with a nylon screw operating with a standard vent tank on muffler pressure. Not sure what it would take to find out, but again my wild ass guess is some kind of leak in the head. That's the only thing that makes sense. I've never checked the head bolts on my engine to see if any have come loose. Some kind of flaw in the head design  or poor fitting gasket??  Or maybe just haunted!!???
  Type at you later,
   Dan McEntee

[Massimo Rimoldi]

Should of mentioned that mine are Bob’s set up running on pressure. Somehow the fuel goes in exh  and engine will run hard not like a two stroke running backwards  if lift alone it will melt Venturi and choke screw I have not tried to figure out why. I never let mine run backwards  long enough to tach and see how fast it was going but It was sounding like it was normal speed I put finger over exh and flooded  it quick as I could.

Regards

Joe Gilbert

It is absolutely normal if you connect the muffler pressure pipe to the uniflow pipe.  When the engine reverses the silencer and the venturi switch roles and the engine runs until the uniflow tube is immersed in the fuel.

Massimo

[Dan McEntee]

It is absolutely normal if you connect the muffler pressure pipe to the uniflow pipe.  When the engine reverses the silencer and the venturi switch roles and the engine runs until the uniflow tube is immersed in the fuel.

Massimo

  I had not thought of that angle on it. I don't run uniflow on mine, but I can't remember if I have the pressure hooked to the fill or overflow, and the other is then plugged. I read about that type of tank set up on the forums here, and that 4 strokes don't necessarily run well on uniflow, and I found that to be true in my case. I get a mild speed up later in the flight , right about the hourglass, but that doesn't bother me too much. I've never thought of running a check valve on a muffler pressure line, but that may be a preventive measure??
   Type at you later,
   Dan McEntee

[Massimo Rimoldi]

...I've never thought of running a check valve on a muffler pressure line, but that may be a preventive measure??
   Type at you later,
   Dan McEntee

I don't think it is necessary to use a ceck valve. I've never used pressure but in any case if you use the manual starting method with the rotation of the prop clockwise (also recommended by SAITO on page 3 of his manual  https://www.saito-mfg.com/PDF/instruction/eng/4st/FA-56Bhp.pdf  ) you will never have a reverse start...

Massimo

[Dave Hull]

A check valve in the exhaust pressure line is not a great idea in my opinion. Too easily clogged up and then you go over-lean. That's based on 2-stroke experience. Similar experience trying to run a check on case pressure for a CL racing setup. A 4-stonker might be different--but might even be worse due to the higher heat?

Thanks for the Saito engine manual, Massimo! I read thru the starting instructions per your suggestion. If I see another one, I'll use the backflip against compression as the preferred technique. (I noted that the factory emphasizes the need for operating using muffler pressure.)

One of the issues we had was the new mind set Dan was talking about with turning the prop twice thru to get back to the compression stroke. Add to that the prop that was recommended was a 3-blade. Add to that all of us were used to running smaller engines like .40's and .46's and you can see that we were not accomplished/confident in operating the big .62. And a lot of guys really didn't want to hold the plane, either. When the new owner wanted to use a starter, but had some issues there...the plane ended up staying home, and eventually traded back to the original owner.

Glad that Mio is getting easy starts with his .56! A scale biplane may be the perfect place for a 4-stonker....