Everything Radial Engines
12-01-2021, 06:54 AM
#3877
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Saito fa 120 r3
Hi all
I bought a new SAITO FA 120 R3 as my first multicylinder engine. Trying to break-in the engine on the bench (according the instrucrions) I noticed that engine's rpm do not change at all by the needle valve. Even if I unscrew it by 6 or 7 (!) turns the rpm remains the same, about 7400 (throttle fully open). So I can not have the engine working with a rich mixture as needed during break-in. After only 1,5-2 minutes the engine becomes also very hot, the metals of the engine smell, so I stop it immediately. Very often one or more cylinders go out of function, but I accept it, as the engine is still new.
What worries me most of all is that the rpm remains the same with all needle-valve adjustments. It alters only with throttle. I checked the tank for any leaks and it is O.K. The muffler is that provided by the factory, i.e. 3 tubes.
The matter is really very disappointing to me and I would appreciate any help.
Thanks
George
I bought a new SAITO FA 120 R3 as my first multicylinder engine. Trying to break-in the engine on the bench (according the instrucrions) I noticed that engine's rpm do not change at all by the needle valve. Even if I unscrew it by 6 or 7 (!) turns the rpm remains the same, about 7400 (throttle fully open). So I can not have the engine working with a rich mixture as needed during break-in. After only 1,5-2 minutes the engine becomes also very hot, the metals of the engine smell, so I stop it immediately. Very often one or more cylinders go out of function, but I accept it, as the engine is still new.
What worries me most of all is that the rpm remains the same with all needle-valve adjustments. It alters only with throttle. I checked the tank for any leaks and it is O.K. The muffler is that provided by the factory, i.e. 3 tubes.
The matter is really very disappointing to me and I would appreciate any help.
Thanks
George
12-01-2021, 07:23 AM
#3878
My Feedback: (62)
George, first off, the small Saito's lack appreciable torque. Use a 13x7 or 14x6 prop. Now in a quiet room, attach fuel line to the carb so you can blow through it. Screw the needle valve down to off and gradually unscrew it. By 1 turn you should be able to hear air flowing through the carb (if you have good hearing) and more as you unscrew. A design issue with Saito carbs is if the idle screw is in too far you also cannot richen the high speed needle. So try to open the idle needle a turn if the high speed needle lacks flow. The small Saito radials, 90r3 and 120 r3 are durable long lasting engines. My 90r3 has outlasted three airframes!! -Tom
When you do these tests, make sure the carb throttle setting is all the way open.
When you do these tests, make sure the carb throttle setting is all the way open.
Last edited by Maxam; 12-01-2021 at 07:25 AM. Reason: additional info
12-01-2021, 08:31 AM
#3879
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Thanks a lot, I will try this asap and let you know again. I am using a 14x6 propeller.
When I screw the needle less than 2 turn the engine stops. It seems that the mixture is very poor and the engine "understand" this, it can not work with such a poor mixture. The contrary is not working: By unscrewing the needle, the engine "does not understand" that the mixture is (?) rich. But I will try tomorrow the idle screw (here is already night).
When I screw the needle less than 2 turn the engine stops. It seems that the mixture is very poor and the engine "understand" this, it can not work with such a poor mixture. The contrary is not working: By unscrewing the needle, the engine "does not understand" that the mixture is (?) rich. But I will try tomorrow the idle screw (here is already night).
12-04-2021, 02:50 AM
#3880
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Yes, it worked Tom, I am so grateful!
I had to open the idle screw by about 3 turns. The rpm adjustment range is not enormous using the needle valve- from about 6800 to 9500 rpm- but at least I know now that I can enrich the engine so that I can break it in correctly. I think 9500 rpm with a 14x6 prop is very satisfactory.
I am going to install this engine to a Seagull P-47 THUNDERBOLT "SNAFU" which I bought specially for this engine. It would be a great dissapointment if the engine could not work.
I think that with a 14x6 prop and 9500 rmp this model will fly well.
Thanks
George
I had to open the idle screw by about 3 turns. The rpm adjustment range is not enormous using the needle valve- from about 6800 to 9500 rpm- but at least I know now that I can enrich the engine so that I can break it in correctly. I think 9500 rpm with a 14x6 prop is very satisfactory.
I am going to install this engine to a Seagull P-47 THUNDERBOLT "SNAFU" which I bought specially for this engine. It would be a great dissapointment if the engine could not work.
I think that with a 14x6 prop and 9500 rmp this model will fly well.
Thanks
George
Last edited by georgek_54; 12-04-2021 at 04:42 AM.
09-28-2022, 07:31 AM
#3882
09-28-2022, 07:46 AM
#3884
09-28-2022, 12:31 PM
#3888
And me!
just been looking at buying a radial for my ‘almost complete’ Flair Stearman. Toying with either the UMS 7-77 glow or the same size 7-90 petrol. Not sure of the advantage of either… both are much larger and heavier than the Laser 200 recommended! I’m guessing additional LiPo needed for either to fire the glow plugs on board or power the spark ignition system???
just been looking at buying a radial for my ‘almost complete’ Flair Stearman. Toying with either the UMS 7-77 glow or the same size 7-90 petrol. Not sure of the advantage of either… both are much larger and heavier than the Laser 200 recommended! I’m guessing additional LiPo needed for either to fire the glow plugs on board or power the spark ignition system???
09-28-2022, 01:46 PM
#3889
And me!
just been looking at buying a radial for my ‘almost complete’ Flair Stearman. Toying with either the UMS 7-77 glow or the same size 7-90 petrol. Not sure of the advantage of either… both are much larger and heavier than the Laser 200 recommended! I’m guessing additional LiPo needed for either to fire the glow plugs on board or power the spark ignition system???
just been looking at buying a radial for my ‘almost complete’ Flair Stearman. Toying with either the UMS 7-77 glow or the same size 7-90 petrol. Not sure of the advantage of either… both are much larger and heavier than the Laser 200 recommended! I’m guessing additional LiPo needed for either to fire the glow plugs on board or power the spark ignition system???
Currently mounted on a Tony Eck built BUSA Newport 28. Ready to fly. 1200 cash. Never opened to inspect. Stored indoors in a climate controlled finished basement.
[email protected]
09-28-2022, 06:13 PM
#3891
My Feedback: (128)
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You run 15% nitro and 18% synthetic in your Evo 777? Heck, I run 5% nitro and 6% lube (11% of which is castor). It’s an earlier UMS/Seidel 770, but basically the same engine, just not bored out. That’s what the manufacturer (UMS) recommends. Buy yourself some pump methanol at a little over $3/gallon, and you can cut your fuel bill in third!
09-29-2022, 04:53 AM
#3892
You run 15% nitro and 18% synthetic in your Evo 777? Heck, I run 5% nitro and 6% lube (11% of which is castor). It’s an earlier UMS/Seidel 770, but basically the same engine, just not bored out. That’s what the manufacturer (UMS) recommends. Buy yourself some pump methanol at a little over $3/gallon, and you can cut your fuel bill in third!
I am very happy with the fuel I mix. If you buy any of them. I would highly recommend my fuel mix.
Aaron-
09-29-2022, 06:02 AM
#3893
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My apologies, Hyjinx, I didn't mean to be judgmental.
Maxam had turned me on to Jackson Solvents in Indianapolis; they sell pump methanol to the karting/Sprint racing community. I've family that way, and every now and then bring about 30 empty fuel jugs and fill them up. I blend my glow fuel per Gierke's recommendations, though these radials use much less oil than he recommended. I've had my 770 since 2013 and it too runs very well on the low oil fuel. Given how expensive glow fuel is these days, if you have access to bulk methanol, it can save some $$$!
Maxam had turned me on to Jackson Solvents in Indianapolis; they sell pump methanol to the karting/Sprint racing community. I've family that way, and every now and then bring about 30 empty fuel jugs and fill them up. I blend my glow fuel per Gierke's recommendations, though these radials use much less oil than he recommended. I've had my 770 since 2013 and it too runs very well on the low oil fuel. Given how expensive glow fuel is these days, if you have access to bulk methanol, it can save some $$$!
Last edited by redball8; 09-29-2022 at 06:07 AM.
09-29-2022, 07:48 AM
#3894
My apologies, Hyjinx, I didn't mean to be judgmental.
Maxam had turned me on to Jackson Solvents in Indianapolis; they sell pump methanol to the karting/Sprint racing community. I've family that way, and every now and then bring about 30 empty fuel jugs and fill them up. I blend my glow fuel per Gierke's recommendations, though these radials use much less oil than he recommended. I've had my 770 since 2013 and it too runs very well on the low oil fuel. Given how expensive glow fuel is these days, if you have access to bulk methanol, it can save some $$$!
Maxam had turned me on to Jackson Solvents in Indianapolis; they sell pump methanol to the karting/Sprint racing community. I've family that way, and every now and then bring about 30 empty fuel jugs and fill them up. I blend my glow fuel per Gierke's recommendations, though these radials use much less oil than he recommended. I've had my 770 since 2013 and it too runs very well on the low oil fuel. Given how expensive glow fuel is these days, if you have access to bulk methanol, it can save some $$$!
I consider fuel and oil additives a small price to pay for my hobby. I pay a local auto parts store 55.00 dollars a five for VP methanol. I pay a local power sports store 22.00 (I think) for quarts of Klotz Technaplate. I pay my local hobby shop 65.00 dollars for two gallons of 30 percent Morgan heli fuel (it contains combustible Mineral based oil that is real smoky and mixes well with the Klotz. I sometimes add straight castor from the lhs but not always.
I buy Amsoil from a auto parts store 1.5 hours from my home and mix it with rec fuel from my local gas station. I don't care what any of all of that stuff costs or how far I have to drive to get it. Even with Biflation and the decimation of oil company profits due to his administration.
No offence intended, none taken.
Aaron Hubbard
Chelsea
Michigan
USA
Further more. I try to remember to pray for my elected officials no matter what they stand for. I hope our nation does the same.
And I hope we all vote for the candidates we believe will lead our great nation into the future. Whoever they are based on personal choices made by the citizenry of our sovereign Republic of States.
Please any and all typographical errors.
Last edited by Hyjinx; 09-29-2022 at 07:57 AM.
09-30-2022, 04:44 PM
#3896
03-12-2023, 01:43 PM
#3897
Hey all, I have a Saito 325R5 and feel I am not getting the RPMs I should. I have changed out the fuel line, adjusted the valves, changed out the plugs. Only other thing I can think of is, check for leaks, try a different nitro%, try a different brand prop. Seems to be running strong and easy start. Might just be all I am going to get out of it.
Can anyone post their numbers. Thanks
I am running
900 FT MSL
29.80 pressure
93% Humidity
619 DA
48F Temp/46F Dew
20% nitro
OSF Plugs
20X8 XOAR PJWWII
3.25 turns on needle - 6400 rpm
about 1100 rpm low
20X10 XOAR PJWWII
3.25 turns on needle - 5900 rpm
about 900 rpm low
I found a post where a guy is running a 20x10 turning 6800rpm, unknown brand, at sea level, with 10% nitro
I have an old article showing
Zinger
74F
46% Humidity
29.98 pressure
20x8 7500 rpm
20x10 6650 rpm
Can anyone post their numbers. Thanks
I am running
900 FT MSL
29.80 pressure
93% Humidity
619 DA
48F Temp/46F Dew
20% nitro
OSF Plugs
20X8 XOAR PJWWII
3.25 turns on needle - 6400 rpm
about 1100 rpm low
20X10 XOAR PJWWII
3.25 turns on needle - 5900 rpm
about 900 rpm low
I found a post where a guy is running a 20x10 turning 6800rpm, unknown brand, at sea level, with 10% nitro
I have an old article showing
Zinger
74F
46% Humidity
29.98 pressure
20x8 7500 rpm
20x10 6650 rpm
03-12-2023, 02:10 PM
#3898
I'm not here to tell you to give up, but are you concerned about not getting enough power that you need out of it? I'm about 1k rpm short on my 7cyl 90cc engine, but it's still plenty of power for scale flying and the engine runs well. If it's going in a war bird then I can understand I guess, but for a biplane I wouldn't be overly obsessed with rpm.
Have you used a laser thermometer to check if all cylinders are running?
Have you used a laser thermometer to check if all cylinders are running?
03-12-2023, 02:19 PM
#3899
I'm not here to tell you to give up, but are you concerned about not getting enough power that you need out of it? I'm about 1k rpm short on my 7cyl 90cc engine, but it's still plenty of power for scale flying and the engine runs well. If it's going in a war bird then I can understand I guess, but for a biplane I wouldn't be overly obsessed with rpm.
Have you used a laser thermometer to check if all cylinders are running?
Have you used a laser thermometer to check if all cylinders are running?
03-12-2023, 02:34 PM
#3900
Since the Saito radials have individual camshafts per cylinder, IF the engine has been disassembled before there is a possibility one of the cams shifted one tooth during assembly.
If I were you I would check individual cylinder timing, because contrary to more conventionally constructed radials, with the Saito cyl 1 being OK does not mean the rest ALSO is timed right.
If I were you I would check individual cylinder timing, because contrary to more conventionally constructed radials, with the Saito cyl 1 being OK does not mean the rest ALSO is timed right.