OS's Fake Crankcase
12-05-2008, 10:13 PM
#1
OS's Fake Crankcase
Take a look at the FSR .10's case. It had the same Schneurle bulges cast in just like the .25, .40, .45, .60, .61 and .90 did. Now, remove the sleeve and look inside. It's a smooth cylinder. No boost ports machined into the case. The ports in the sleeve extend down into the case to receive the charge.
My guess is that OS wanted this engine to have the same outward appearance as the rest of the FSR line, so they cast a case with the fake bulges. There are three: one in front, one on the side and one on the back, just like the other FSR's, except these are all purely for looks.
David
My guess is that OS wanted this engine to have the same outward appearance as the rest of the FSR line, so they cast a case with the fake bulges. There are three: one in front, one on the side and one on the back, just like the other FSR's, except these are all purely for looks.
David
12-05-2008, 10:20 PM
#2
RE: OS's Fake Crankcase
RD, That extra material does help out when one of these guys hits the dirt at 60 mph. I'm always amazed by the punishment little model engines can withstand. The extra material also gives guys like Andy W. something to whittle on during the winter.
12-05-2008, 10:22 PM
#3
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RE: OS's Fake Crankcase
I have Two of these and they are the same. Also the cylinder is cast, if you look at the transfer ports from the outside edges, you'll notice the rough finish. One thing I have noticed is mine turn up to 19,000 RPM on omega 10% with a MAS 7X4 wide blade. I have never seen an .09 or .10 that would do this.
12-05-2008, 10:40 PM
#4
RE: OS's Fake Crankcase
I just got this one for $16. I cleaned it up and I will run it tomorrow on Powermaster GMA 10/22 with the Rev Up 7x4 in the artsy photo. The Italians called that [link=http://en.wikipedia.org/wiki/Chiaroscuro]Chiaroscuro[/link]. It is a bit Caravaggesque.[8D] Man, I hope mine gets near 19K!
David
David
12-06-2008, 12:56 PM
#7
RE: OS's Fake Crankcase
ORIGINAL: gkamysz
...To get an A+, you need to notice that the bulges don't even match up to the ports in the liner. [sm=confused.gif]
...To get an A+, you need to notice that the bulges don't even match up to the ports in the liner. [sm=confused.gif]
David
12-06-2008, 02:58 PM
#8
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RE: OS's Fake Crankcase
Thunder tiger made a clone of this in the '70s. I don't think the metalurgy was as good as OS. Of course you know that this was the first OS to turn the liner in the schneurle engine to allow to use a cheaper floating wrist pin without snap rings. This engine was the guinea pig for the design.
12-06-2008, 03:22 PM
#9
RE: OS's Fake Crankcase
kersplat, when I first put the sleeve back in the case I had it lined up like a typical Schneurle (I was paying attention to the case bulges) and I wondered to myself what was going to keep the Teflon pads from catching in a port.
Then, when I looked into the exhaust port to line up the sleeve I saw that it must be rotated back several degrees. Sure enough, as you point out, this allows the pin to ride over bridges on the sleeve. This is when I removed the sleeve again and discovered that the bulges are only cosmetic. I can tell I followed in the same exact footsteps as you.
To be honest, I really hate removing and replacing pin clips on anything smaller than a forty. So, I'm glad this engine was designed this way.
David
Then, when I looked into the exhaust port to line up the sleeve I saw that it must be rotated back several degrees. Sure enough, as you point out, this allows the pin to ride over bridges on the sleeve.
This is when I removed the sleeve again and discovered that the bulges are only cosmetic. I can tell I followed in the same exact footsteps as you.To be honest, I really hate removing and replacing pin clips on anything smaller than a forty. So, I'm glad this engine was designed this way.
David
12-06-2008, 04:47 PM
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RE: OS's Fake Crankcase
Dave, have you run this engine yet? The reason why I ask is I dissassembled one of mine after a minor dork and cleaned the engine parts by rinsing without scrubbing and when I reassembled the engine the compression was not good. I didn't get the liner aligned exactly as before [:@] Pooh.
12-06-2008, 05:17 PM
#14
RE: OS's Fake Crankcase
Yes, I ran it earlier today. After reassembly the compression was down on mine, too, but after a few short runs it started coming back. I was careful to put the piston back in facing the same way it came out. I usually don't mess with honed piston/sleeve assemblies for this very reason. It starts easily and seems to run fine. I will run it some more tomorrow and get a tach reading. I use Powermaster GMA fuel with lots of castor in all my oldies and that seems to help with well worn engines. I may need to wear it back in and build up a little varnish to get it back where it was.
David
David
12-08-2008, 08:45 PM
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RE: OS's Fake Crankcase
ORIGINAL: rainedave
Well, I think mine is just old and worn out. The best I could get on 5% nitro and an APC 7x4 was 15,825. That seems pretty weak. I'd certainly break 16K with 15% but not 17K.
David
Well, I think mine is just old and worn out. The best I could get on 5% nitro and an APC 7x4 was 15,825. That seems pretty weak. I'd certainly break 16K with 15% but not 17K.
David
