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Jan 26, 2016, 10:37 PM
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Mini-Review

Old Saito FA-40 refurbishment


I bought this engine here on RCGroups. I knew by the ad picture it would be a "project". I was told it was test ran and was fine. I made what I thought was a fair offer to his asking price and the seller accepted. A few days after I paid, he contacted me to say he went to test run it again before sending it out and it ran for three minutes and quit and now the valves won't work and wanted to refund my money. I said, "what the heck, I'll take a chance on it". You don't see too many of the older FA-40's, so I didn't want to lose it.
Just at as I enjoy refurbishing old kit and plans built planes to give them "new life", I like doing the same for old engines, especially four strokes.
When I received the engine, it was just like it was in the ad picture... DIRTY! A lot of caked on hardened dirt and grime. The engine turned over, but was very gritty and I could tell the valve train was not working. After pulling off the valve covers I found out why...the exhaust valve rocker arm was seized to its mounting pin. These pins usually don't like to come out on older engines without some major persuasion (heat and torque) and the flat head on the pin can easily strip.
Long story short....I did get the pin out. I completely stripped the engine down and thoroughly cleaned all parts. I have all new gaskets and o-rings.
As you can see in the pictures, the piston head was black, but it was gooey, not hardened like high run time engines. This "crud" was found throughout the engine. There was, surprisingly, no rust or corrosion. After cleaning, I don't really think this engine had a lot of run time as evidenced by very little wear on the cam and piston. I think this was just a really neglected engine that sat for a long time. I can tell by moving the piston up and down in the bore that it has an excellent seal. I leaked checked both valves and they seal perfectly.
I am now waiting for a set of crankshaft bearings to reassemble. I'm sure it'll run great. Will update with pics and video of the run.
Last edited by kimchiyuk; Feb 02, 2016 at 10:20 AM.
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Jan 27, 2016, 07:43 AM
Cat Man
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Man that was one grimy engine! Just the way I like them too. Great job with all of the photos. I start getting so involved with the dis assembly I neglect to stop and take photos. Those clean up parts look great and the wait for bearings seems long.... I'll be waiting to see the video.
Jan 27, 2016, 08:01 AM
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Thanks, Dave. One more "oldie" spared from the garbage or eternal rest in a drawer. Gonna save em' all...one engine at a time!
Jan 27, 2016, 08:38 AM
Cat Man
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I almost scored one of these FA-40's from Ebay a few weeks ago. It was NIB but it was a bit more than I wanted to pay. That looks to have considerable run time on it judging by the carbon build up on the exhaust stem. It takes a while for the top of the piston on a 4 stroke to turn black.
Jan 27, 2016, 08:40 AM
Cat Man
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Can you post a picture of the screwdriver you used to get the rocker pin out? What all did you have to do to get it freed up? On that 45S I couldn't get it out at all. I used alcohol, oil, PB Blaster, several heat cycles and a ground down screwdriver just to get it out with no luck at all.
Jan 27, 2016, 08:47 AM
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Quote:
Originally Posted by dmrcflyr2
That looks to have considerable run time on it judging by the carbon build up on the exhaust stem. It takes a while for the top of the piston on a 4 stroke to turn black.
Yeah, it's difficult to estimate run tun time as there are so many variables: type and quality of fuel, how it was ran, state of tune etc, I know you know all of this.
The black on the piston was a gelatinous goo; best way to describe it. It actually wiped right off and the top of the piston was a light golden color. There was no black or hardened carbon left over. This was definitely used and was no "spring chicken", but actual run time is difficult to estimate.
Jan 27, 2016, 08:54 AM
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Quote:
Originally Posted by dmrcflyr2
Can you post a picture of the screwdriver you used to get the rocker pin out? What all did you have to do to get it freed up?.
I heat the rocker arm and the aluminum where the rocker pin threads into with a butane torch.
The screwdriver I used is an old wooden handle flat head I had laying around...probably older than I am. The end was broken, so I dremeled the end to have a tight fit into the flat head on the rocker arm screw. I like the wooden handles as you can really get a good grip.
Jan 27, 2016, 09:03 AM
Cat Man
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Damn it. I had a micro torch too but used a head gun only. I guess I was afraid of get too hot. How long did you have the flame on it?
Jan 27, 2016, 12:32 PM
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Quote:
Originally Posted by dmrcflyr2
How long did you have the flame on it?
I applied it several times, maybe for 10 seconds or so each time trying to loosen in between. I don't know if the heads are straight aluminum or an alloy, but if the rocker arm pin didn't come loose, this head would've been garbage anyway...so I "let her have it"!
Feb 06, 2016, 09:48 PM
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Before and after pics:
Feb 07, 2016, 04:34 PM
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Run video


Here's the run video. It's short, but gets the point across. This was my first attempt at recording an engine run, so pardon the amateur quality.
The engine ran great! Max RPM of 10,150 using a MA 11X5 prop and S&W 10% castor/synthetic mix. It has a great idle. I actually could get it below 2000 RPM; not that I'd fly it that way, but shows that it's a well running engine. I richened the engine to 9800 RPM and it stayed at that RPM for as long as I wanted. After running it has even better compression, as expected. Another engine to put on the shelf for a someday build.
Saito FA-40 old version (1 min 45 sec)
Feb 07, 2016, 04:48 PM
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FA-40 and FA-45 comparison.


I did run my FA-45 to compare to the FA-40. The same prop and fuel was used. Surprisingly, there was only a difference of just over 150 RPM higher on the 45.
I'm not sure why Saito would have taken the same case to make a smaller displacement for very little difference in RPM. I don't think there are too many people that could even tell that small of a difference. It makes me wonder how many of these .40's were made.
Feb 07, 2016, 06:04 PM
Cat Man
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Freaking sweet video! Yes that is a NICE runner. Let me know if you ever think of selling it.
Feb 07, 2016, 06:23 PM
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Quote:
Originally Posted by dmrcflyr2
Freaking sweet video! Yes that is a NICE runner. Let me know if you ever think of selling it.
Will do. Thanks for the compliment. I see building some sort of camera fixture in the near future.


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