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1992 OS 91 Surpass Torque Spec's.

Old 03-16-2005, 08:54 PM
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Default 1992 OS 91 Surpass Torque Spec's.

Dear Bax,
I just cleaned a 13 year old O.S. 91 Surpass with the "crock pot & antifreez" method to clean the engine inside and out, and hopefully free the intermittant sticky intake valve I wound up with over the years. Over the last year of use (flying), the valve would sometimes stick the first time I flipped it over cold at a new flying session and prevent compresson until I got some new fuel into the engine. I also had instances where the engine would stop ever so abruptly after running it on the ground, and also in mid flight!. After I landed the airplane, there didn't seem to be anything binding. The engine would start up agian like nothing happened. Weird problem ! Per your earlier recommendation (last year I think), I would like to tear down the engine more and clean up the inside better. Maybe ther's some varnish in there.
O.k., so now the engine is very clean, but I wanted to mention that the valve didn't free up all by it self. I decided to drip a few drops of rislone oil into the push rod tube and rocker areas. After lifting the rocker arm with my fingernail, the valve is working freely again. This doesn't comfort me though since the valve stuck before, and I belive what ever "gunk" or defect was inside the egine is still there now.
Before I do any dissassembly of the crankcase, I would like to try to get the hex scerw torque values for the crank case parts. Are the torque specifications something I can look at on line somewhere, or maybe have sent to me ? Also, if the sticky valve probelm is caused by a specific anomaly you're familiar with, let me know what that is befoe I tear down the engine completely.
Thanks for being there,
Mike D'Amico,
Palm Bay, Florida.
Old 03-17-2005, 10:48 AM
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Default RE: 1992 OS 91 Surpass Torque Spec's.

We're sorry, but we don't have torque specifications for your O.S. FS-91. We just tighten the bolts snugly.

As far as what could make a valve stick, once you've cleaned-up any carbon, congealed fuel, dirt, etc, then the most likely cause of valve sticking is a bent valve stem. It doesn't take much to cause the valve to stick. One attempted start with hydraulic lock can cause it. So can detonation when the engine's running. Over many years, one or the other is likely to have happened.

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