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Engine basics => Engine set up tips => Topic started by: frank mccune on October 04, 2018, 03:02:31 PM
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Hello All:
One of my flying mates could not get a decent engine with his "old" ST .56 engine. No matter what he did, it would lean out and die very lean. He changed everything, tank, compression props etc. but nothing would provide a steady run. The engine started first flip and had one ring on the piston. This engine would run a very nice 4 cycle for the first half of the tank but then would go screaming lean, overheat and seize up. I suggested that it was not "broken in" but what do I know
Today he showed up with the same set up but with another "new" ST .56 that had two rings and ran like a fine Swiss watch. No problems!!!!! He used the same tank set up, fuel and prop on both engines. A great 4 cycle run the entire flight!
Why would the first engine perform so badly. Both are "new." I still think that the ring may be too tight or just needs to be run more.
Suggestions and/or comments?
Frank McCune
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Some on would have to LOOK at the engine, in person ... You cannot diagnose that over the text box, All you can do is speculate the many things that could cause it, and yes a ring too tight can make for overheat and runaway
So can a muffler, also so can a crank spinning in a bearing race without the bearing moving, this is common on ST engines
Air leaks can cause this, and a 40 plus year old NEW engine can have locked pins, locked bearings, dried leaking gaskets etc...
Randy
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Earlyer Super Tigres , around 65 & earlier , were alledgedly built with harder liners & set up closer .
Then the imprter whined about them takeing forever to run in . Took forever to run out too . ;D
Wondering if those 56s have the same head bolt pattern P.C.D. as the 60 Lite ??
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Earlyer Super Tigres , around 65 & earlier , were alledgedly built with harder liners & set up closer .
Then the imprter whined about them takeing forever to run in . Took forever to run out too . ;D
Wondering if those 56s have the same head bolt pattern P.C.D. as the 60 Lite ??
All of the early ST 56 I have seen had a chromed steel liner
Randy
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O.K. , to get to the thin end of the wedge ,
(https://static.rcgroups.net/forums/attachments/4/1/2/3/1/8/a9719449-33-Super%20Tigre%2056%20R-C%20-%203.JPG)
The PLAIN BEARING 56 , much like a Double Star Light ( 60 ) ,
If the HEAD BOLT PATTERN matches the 60 , the next step might be trying to sort a 60 liner - The early thin ones still do big a diameter ?
& would it fall in half , overboring the case for the standard ST 60 Liner . ( Noteing on the 51s the B B & plain bearing part numbers match for liner ) .
Just a thought . :-\