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saito 120

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Old 05-21-2014, 02:52 PM
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Stick 40
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Default saito 120

Hi,
anyone have the valve clearance on a saito 120?

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Old 05-21-2014, 09:30 PM
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Saito calls for .002"-.004" valve clearance with the engine "cold".
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Old 05-24-2014, 04:59 AM
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thanks a lot, its a used engine. Did not get a book with it, but seems to run very well.

Just though I would check the valves, some guys are not into that stuff and thats alright.

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Old 05-24-2014, 07:06 AM
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As long as the valves are not held open when the engine is cold the valves can have less than .001 clearance. The pushrods are steel and the rest of the engine is aluminum. This means the cylinder will "grow" longer faster/more that the pushrods so the valve clearance will increase with heat.

With the above said I run my valves as tight as I can. I've had no issues to date doing this. My reasoning for doing this is to gain a slight advantage in performance. It's the motor head in me doing this.

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Old 05-24-2014, 04:43 PM
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I have had saito's for many years and always set them to factory spec. Never had a problem and they always have plenty of power.

I looked at the Saito site , but did not fine the setting . I have never had a saito this big before, that is why the question.

I will still set them .002 to .004

thanks anyway

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Old 05-24-2014, 05:28 PM
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While what "motorhead" kenh3497 said is technically correct, in the real world benefit is unnoticeable. The theory is what ever amount you reduce the valve lash by, you get a corresponding increase in valve lift (valve opening). The danger is, if you reduce the valve lash too much, I.E. to zero, you will loose the oil film between two metal parts, valve and rocker arm, vital to these two not wearing each other out in very short order. A .001"-.002" increase in valve lift on a 1.20 size four stroke model airplane will net you nothing you can see. If you loose the lubricating oil film between your valve train parts and they wear out quickly (and they will), you will notice that! Not good! Be careful playing this game as there is very little to gain and much to loose. As a former championship winning racing engine builder, I have played this game with SCCA racing sports cars engines and found that a 300+ HP engine on the dyno would only show us 1 or 2 HP gain by reducing the valve clearance, so on a 2 HP model airplane engine what are you going to gain?? Follow the manufacture's spec and keep the engine running well for a long time.

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Old 05-24-2014, 05:34 PM
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Stick 40, BTW .........The .002"-.004" valve setting spec that I quoted you came directly from my 1.20 Saito instruction book. I have two of these engines, one in a 1/4 scale J-3 Cub and the other in a Rascal 110. Great engines, what are you going to fly yours in?
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Old 05-25-2014, 05:29 AM
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Not sure yet, I have a couple of planes in mind.

One of our local guys passed away and I bought a three of his larger engines that were left over from his RC estate sale. 2 saito's 120's and one YS 120. The price was good as they did not sell and she wanted all the stuff gone.
I bought more, but this was left overs, and we were trying to help her.

I do have a 1/4 scale cub, I may go that way . I have not gotten around to the other two yet. I have more projects than time.

Thank you all for the help.

As to getting more power out of them, I wonder if the Black Knights give a little more. The black may dispense heat better, maybe not much but a click or two leaner??? Back in the day Clarence Lee stated that radiators were black so as to gave off heat better....

did you find the book on this engine on line, if so can you give me the link. I would very much like to have it.

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Old 05-25-2014, 08:11 PM
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Your 1/4 scale Cub would LOVE that Saito 120 engine. Great match! I flew both of my Saito 120 powered aircraft today. That's a 1/4 scale J-3 cub and a Sig rascal 110. Had a great day flying 4 large scale planes in near perfect weather. As to your question on the Black Knight versions of the Saito, no the black color will not make any more power. If it gives off more heat because of the color that will not result in any power increase, just better cooling and the cooling difference is marginal at best. Most aluminum racing radiators don't get painted black, they stay natural silver. Good airflow over your engine especially in the cylinder head and upper block area is what is needed to keep our air cooled model engines happy. The Saito instruction book that i quoted the valve lash specs from did not come offline but rather is the original instruction book that came with one of my engines when purchased new. I don't know where to send you to get a copy. Happy flying Oh, and your welcome for the help.
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Old 05-26-2014, 08:20 PM
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OPPS, what we both called a "black knight" is actually a "Golden Knight". I claim a "senior moment" with too much sun that day!!
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Old 05-28-2014, 07:53 AM
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your right. I was thinking of the cyl. being black. no big deal, we knew what we were talking about. It was just the valve covers that were gold, are they worth more now that gold has gone up??? LOL

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