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Old 07-18-2019, 10:03 AM
  #41451  
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Saito FA80 is rated for 1.3 hp. Seems it would turn a 12x8x3 at least 9k, probably closer to 9300?
Old 07-18-2019, 10:36 AM
  #41452  
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I got a chance to work on it today. I got 8700 on the 12x8 3 blade, so it's in the ballpark power wise. I think I did have an issue with the timing, as I can go a good bit lower in the throttle setting before it dies. But something still isn't right.

The idle is still frustrating me. I can get it to 2300, but after a few seconds it starts missing a lot and then dies. Leaving on the glow heat keeps it steady and at a higher RPM. I didn't measure it with glow heat, but I'd guess around 4000. So that indicates a rich mix, right? But then leaning it makes it miss more and die. I tried raising the RPM to keep it running so I could do adjustments, but it dies if I lean it any more at 1/2 throttle too. I had peaked the HSN at 8700, then richened it to 8400 before working on the LSN.
I own a Saito .72, and never had these kinds of problems. It took me 5 minutes to tune that engine, and I've never touched the LSN again in the last 4 years. That engine, also with an OS F plug and 10% fuel, was very predictable with leaning/richening the needles. This one acts right on the high end, but the low end just doesn't make sense. As stated above, it held air pressure fairly well (very slow leaking) in the intake pipe and was just as good when I blew into the fuel line. I did reset the valve lash when I did the timing too.
So any other thoughts?
Old 07-18-2019, 11:13 AM
  #41453  
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Cracked intake manifold maybe? David gets a surprise at 3 min-40 sec into this vid.

Last edited by Glowgeek; 07-18-2019 at 11:20 AM.
Old 07-18-2019, 11:46 AM
  #41454  
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The intake is a little dented (how does that even happen?) but there's no cracks.
Old 07-18-2019, 12:08 PM
  #41455  
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Originally Posted by jester_s1
The intake is a little dented (how does that even happen?) but there's no cracks.
Assuming everything is reassembled and adjusted correctly, try a new glow plug just for fun. It's rare but OS has shipped out a few bad plugs. The plug from a good runner like your 72 is an excellent candidate.

Did you remove the piston to make sure the ring groove is clean and that the ring is freed up? Carbon and castor gunk are evil!

Triple check your fuel lines?

When you stated earlier that something was leaking a little air, where was it leaking?

Last edited by Glowgeek; 07-18-2019 at 12:18 PM.
Old 07-18-2019, 12:20 PM
  #41456  
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I did in the initial clean up. I soaked everything in old fuel to get the gum off. I did check the ring and saw it could rotate in the groove. The fact that the engine has good compression would indicate to me that the ring is fine.
Old 07-18-2019, 01:46 PM
  #41457  
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Originally Posted by jester_s1
The intake is a little dented (how does that even happen?) but there's no cracks.
I spun an extra 220 running an fa82 in and the engine and intake pipe got slammed back into the bulkhead which put a large dent in it, probably what happened to your fa80. My fa82 had a bent crank which i replaced, the funny thing was that the bent intake had no effect on max rpm.

You don't say if your fa80 is in the spitfire or on the bench. I assume your fuel tank is properly located height wise and there is tank pressure. It may sound silly but i've had air leaks in silicone fuel tubing that looks perfect to the naked eye, but when replaced solves the tuning problem. I think lonnie is on the right track and it's something silly like that, it's happened to me.

ps leave the hsn peaked while you adjust the lsn cheers
Old 07-18-2019, 03:07 PM
  #41458  
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I'll go back through the carb and make sure the seals are good. I didn't replace them all when I did the rebuild because blowing air in showed them sealed.
The small leak was in the intake pipe. I was blowing as hard as I could and could feel a small loss of pressure. It wasn't even enough to make a hiss.
I'll check the tank plumbing. It's all new, but that doesn't mean it can't be faulty. It's happened to me before.
Yes, the engine is in the Spitfire. The tank height is pretty even with the spraybar in flight attitude. It sits a bit below on the ground.
Old 07-18-2019, 04:10 PM
  #41459  
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Jester, I admire your tenacity. You'll find the fault eventually and have a great running Saito. Do let us know what you find, it may help someone else who pops in here with similar Saito weirdness.
Old 07-18-2019, 04:12 PM
  #41460  
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Intake leaks have the greatest influence at lowest speeds. At high speeds the slight air leakage is usually compensated by needle adjustments.
Old 07-19-2019, 02:20 AM
  #41461  
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Originally Posted by jester_s1
I got a chance to work on it today. I got 8700 on the 12x8 3 blade, so it's in the ballpark power wise. I think I did have an issue with the timing, as I can go a good bit lower in the throttle setting before it dies. But something still isn't right.

The idle is still frustrating me. I can get it to 2300, but after a few seconds it starts missing a lot and then dies. Leaving on the glow heat keeps it steady and at a higher RPM. I didn't measure it with glow heat, but I'd guess around 4000. So that indicates a rich mix, right? But then leaning it makes it miss more and die. I tried raising the RPM to keep it running so I could do adjustments, but it dies if I lean it any more at 1/2 throttle too. I had peaked the HSN at 8700, then richened it to 8400 before working on the LSN.
I own a Saito .72, and never had these kinds of problems. It took me 5 minutes to tune that engine, and I've never touched the LSN again in the last 4 years. That engine, also with an OS F plug and 10% fuel, was very predictable with leaning/richening the needles. This one acts right on the high end, but the low end just doesn't make sense. As stated above, it held air pressure fairly well (very slow leaking) in the intake pipe and was just as good when I blew into the fuel line. I did reset the valve lash when I did the timing too.
So any other thoughts?
Dying slowly is a sure sign of a too rich LS needle, quitting instantly is a sure sign of too lean. Paper HP is the most misleading stat we get.
Old 07-19-2019, 03:57 AM
  #41462  
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It takes a very small air leak to upset idle . Many leaks are quite erratic which is reflected in erratic adjustment.

Old 07-19-2019, 03:57 AM
  #41463  
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Originally Posted by Hobbsy
Dying slowly is a sure sign of a too rich LS needle, quitting instantly is a sure sign of too lean. Paper HP is the most misleading stat we get.
Dave, in Jester's original description of dying at idle he indicated that the rpm would first fluctuate wildy. Neither richening or leaning the lsn helped.

As for paper HP I would agree, if we weren't talking about Saito. The saitos I've worked on and tested have produced numbers very close to or slightly exceeding advertised. Most importantly the advertised HP was produced within useable rpm ranges and prop sizes. Even your own posted results in the tachometer thread show that Saitos make the numbers. The exception would be the FA82 listed as 1.5 hp, no way it makes .20 hp more than an FA80 in factory configuration, especially if compared to the early high compression FA80 which by your own testing exceeds factory spec'd hp by almost 10%.

Even though I often talk about about peak numbers and hp ratings I'm not a "peak freak", I simply use those numbers as a general indication of engine health and comparison.
Old 07-19-2019, 06:36 AM
  #41464  
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I think you guys are right. It has to be an air leak. The rich running at idle and then quitting suddenly as if lean when I tweak the needle are indicators. I've seen this from bad fuel before too, but I ran this fuel in a 2 stroke last week with no problems. Hopefully new seals all around will take care of it.
Old 07-19-2019, 08:41 AM
  #41465  
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When setting the idle needle, I alway open the throttle a bit, then make the slight needle change in the desired direction. After that, return the throttle to idle to check results.

Trying to tweak the needle at idle is often futile as screwdriver pressure can move the throttle barrel inward thus leaning mixture even further than the screw alone dictates.

Yep, when rich it does this and when lean, it does that,

With an intermittent air leak, it can do both on a whim of its own.
Old 07-19-2019, 09:00 AM
  #41466  
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Interesting Gary, I'll try that for the last very fine lsn adjustments. When course leaning the lsn I adjust my lsn at idle and go immediately to wot to check peak and adjust if necessary, then return to idle and wait for the new adjustment to take affect. I do that to totally clear out the intake tract from excess fuel, kind of a system reset.
Old 07-19-2019, 10:21 AM
  #41467  
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Doing it Gary's way will also assure the best mid range and transition. If the idle speed ends up being 2,200 instead of 1,750 or 1,800, it's a safer flying idle speed anyway.

This Saito FA 40-a idle is so smooth and nearly silent that I just stopped right there.

Last edited by Hobbsy; 07-19-2019 at 10:31 AM. Reason: Add picture
Old 07-19-2019, 11:39 AM
  #41468  
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Nice numbers Dave, niiiiiice tach.
Old 07-20-2019, 02:24 AM
  #41469  
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Here's a pic of my dear old departed dog called saito. He was very unkind to cats in the back yard and had a bad habit of chewing and shaking things he didn't like the look of, heli parts and two strokes were a prime target so i never took him to a club flying day, tho there were times when i felt like it.


Nice farm dog

Originally Posted by Hobbsy
No real need to remove the cam from it's housing unless there is something visibly wrong with it.

Pete, the closest I've been to owning sheep is my Australian Sheep dog, his name is Nick, short for St. Nicholas, he'll be 10 years old on Thanksgiving. He's a great dog and if a cat happens to be near the center of the yard he can catch them before they get over the fence. He doesn't bite them or harm them, he just simply runs over them, it makes them awful mad. Did I say he's fast?
St nic sounds like a great dog dave will post a pic, we also call them blue heelers over here if we are on the same page. Beautiful nature.
Old 07-20-2019, 02:58 AM
  #41470  
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Nick, when he was about 2 months old. That TNC met it's demise when I did the hack job on my fingers. Between the EMT's arriving, the ride in the ambulance and 7 hours in the hospital I left the TNC out on our out door fire place. It stormed that night and it has refused to work since. No amount of drying out or Electronic Cleaner spray will revive it.

27 stitches and it was done by an OS 62, not a Saito.


About 2 months old
Old 07-20-2019, 10:23 AM
  #41471  
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The Norwegian Princess would have fixed that with 27 Bandaids, given me a safety lecture and sent me out to put the stuff away.
Then sent me off to bed without my nightly treat.
Old 07-20-2019, 04:01 PM
  #41472  
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Really getting the hang of CorelDraw and the Laser software. Almost ready to burn wood for the Liberty Sport wings. They wont be a perfect match due to the learning curve(actually me being impatient and cutting out a batch from 1/8th sheet) They are off just a little bit for the forward stringers, so had to make sure all the following ones match up. When satisfied then I have 6 3x18 sheets to cut out.

Then I will attempt to make some gaskets.
Old 07-20-2019, 04:33 PM
  #41473  
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acdii aka Bruce, can you import scans/pdf files into CorelDraw? If so it would be a snap to scan in a traced gasket? Another way would be to trace around a rocker cover and then use the offset command in the software to draw the inside of the gasket for you? Can you import .dwg files from AutoCad or .dxf files?

Last edited by Glowgeek; 07-20-2019 at 04:52 PM.
Old 07-20-2019, 05:14 PM
  #41474  
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Yes, but the accuracy is not the greatest. For the crankcase gasket, it can be done in Lightburn easy enough. Two circles of the proper diameter, then four more for the corners, then weld them and the inner portions of the objects disappear, leaving just the outline. THen four circles for the bolt holes and burn it.


I can import a scan, then add a layer over it and trace it using bitmap trace. the problem I encountered is that the lines aren't sharp, too thick, and I wind up with squiggly lines instead of a smooth cut path.



So what I have found to be a more accurate way is to create a rectangle of the proper dimensions, and then create the rib inside the box. I use the main spar box as the reference point for everything and the last 4 ribs I did this way came out perfect.
Old 07-20-2019, 11:53 PM
  #41475  
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Originally Posted by Jesse Open
The Norwegian Princess would have fixed that with 27 Bandaids, given me a safety lecture and sent me out to put the stuff away.
Then sent me off to bed without my nightly treat.
Hey!! that sounds like something my mother would do...you sure we're not related dad ?

Dave i remember you posting those pics back when that happened and they still look painful now. It always astounds me how we all take our limbs and digits for granted till something like that happens and you realise how big an impact it has on day to day life when parts won't work because of plaster splints or bandages, which begin to smell after a while, but not as bad as hospital food. Did you get full movement back?

Jester was wondering if you have had time to go over the fa80 carb and did you replace the tiny o ring on the hsn ?

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