OS 20 piston and cylinder
03-07-2007, 02:28 PM
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OS 20 piston and cylinder
Hi
I just received an OS 20 piston and cylinder Part #2203010
and have noted some differences
The engine I have is marked, Max OS 20, CK marked on the underside of 1 mounting flange and the #2001 also on the crankcase. I have noticed some differences between the original and new parts, and would appreciate your comments
# 1 new piston is missing two port holes on skirt and protrusion on crown
# 2 new cylinder does not have same port hole location and sizes as old
# 3 head does not fit over new cylinder, ID appears to be smaller...
Is this the right part for the engine I have, or did I miss something when I found that part # on the OS site??
Suggestions!!! see attached picture for more detail on original parts...
WHacker
I just received an OS 20 piston and cylinder Part #2203010
and have noted some differences
The engine I have is marked, Max OS 20, CK marked on the underside of 1 mounting flange and the #2001 also on the crankcase. I have noticed some differences between the original and new parts, and would appreciate your comments
# 1 new piston is missing two port holes on skirt and protrusion on crown
# 2 new cylinder does not have same port hole location and sizes as old
# 3 head does not fit over new cylinder, ID appears to be smaller...
Is this the right part for the engine I have, or did I miss something when I found that part # on the OS site??
Suggestions!!! see attached picture for more detail on original parts...
WHacker
03-07-2007, 03:22 PM
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RE: OS 20 piston and cylinder
The part you ordered, 22303010 CYL & PISTON 20FPABC, is not for your engine. You have the old O.S. Max .20 R/C engine. The parts you ordered were for the O.S. Max .20 FP engine. They are of completely-different designs.
The old O.S. Max .20 R/C was of the old crossflow-scavenged design. You can tell that by the baffle on the top of the piston. It went out of production in the late 1970's or so. The O.S. Max .20 FP engine replaced it. The .20 FP is a schneurle-ported engine, and does not have a baffle on the piston. Very likely, the bore and stroke were different.
Parts for your engine are no longer available from us or from O.S., in Japan. The engine's been out of production for too long. You'll have to try to find parts through one of the hobby retailers who specialize in finding parts for the engine collectors' market. They usually advertise in small ads in the model magazines or in the classified sections of those magazines. You can also inquire or search online sources, such as the RCU Marketplace or other trading/auction sites.
The old O.S. Max .20 R/C was of the old crossflow-scavenged design. You can tell that by the baffle on the top of the piston. It went out of production in the late 1970's or so. The O.S. Max .20 FP engine replaced it. The .20 FP is a schneurle-ported engine, and does not have a baffle on the piston. Very likely, the bore and stroke were different.
Parts for your engine are no longer available from us or from O.S., in Japan. The engine's been out of production for too long. You'll have to try to find parts through one of the hobby retailers who specialize in finding parts for the engine collectors' market. They usually advertise in small ads in the model magazines or in the classified sections of those magazines. You can also inquire or search online sources, such as the RCU Marketplace or other trading/auction sites.
03-08-2007, 11:55 AM
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RE: OS 20 piston and cylinder
Hi
Thanks for the quick response Bill..
That explains the difference then ...
I guess I should have taken this apart and posted pictures here before I order this part..
So, much for the new, stronger next 30 years for this engine!!!
I guess it will soldier on the way it was..
Amazing though, at least 30 years old and still running....
Hope the LHS doesn't mind me returning these parts.....??
Anyone have a new piston/ cylinder, to fit this 'antique' , sitting in a drawer somewhere??
Whacker
Thanks for the quick response Bill..
That explains the difference then ...
I guess I should have taken this apart and posted pictures here before I order this part..
So, much for the new, stronger next 30 years for this engine!!!
I guess it will soldier on the way it was..
Amazing though, at least 30 years old and still running....
Hope the LHS doesn't mind me returning these parts.....??
Anyone have a new piston/ cylinder, to fit this 'antique' , sitting in a drawer somewhere??
Whacker
02-05-2011, 07:13 AM
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RE: OS 20 piston and cylinder
Hi Bill,
do you still have the OS20FP ABC piston liner set?I would like one or two to keep my 20FP`s performing well and would like to reduce aOS25LA down to a 20 size to fly in a free flight class called SLOP which is restricted to plain bearings engines maximum capacity of 3.5 running on suction fuel feed.Apart from needing the pin locating groove in the cylinder filed out a little the parts appear interchangeable.I can machine the head to suit and I will also require head shims. Can you or anyone help?
Regards
Phil
do you still have the OS20FP ABC piston liner set?I would like one or two to keep my 20FP`s performing well and would like to reduce aOS25LA down to a 20 size to fly in a free flight class called SLOP which is restricted to plain bearings engines maximum capacity of 3.5 running on suction fuel feed.Apart from needing the pin locating groove in the cylinder filed out a little the parts appear interchangeable.I can machine the head to suit and I will also require head shims. Can you or anyone help?
Regards
Phil
02-07-2011, 07:21 AM
#5
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RE: OS 20 piston and cylinder
The piston/cylinder set for the old O.S. Max .20FP engine has been long discontinued. The part numbers are no longer listed in the O.S. inventory listings...only in the old parts books. In fact, all parts for the FP-series engines have been discontinued, except those very few parts that may be used in later engines.
