ORIGINAL: airbusdrvr
Below is a quote from another RCU forum by Bill Baxter reqarding torque values for OS engines:
''O.S. does not specify torque values. They really aren't needed. We've only used torque wrenches on certain gasoline-fueled engines, and then only on specific parts of those engines where the manufacturer states that tightening to a specific torque value is absolutely required.
_____________________________
Bill Baxter, Manager Hobby Services/Futaba Service/North America
3002 N. Apollo Dr. Ste. 1 Champaign, IL 61822 USA
Service Phone: 217 398-0007
Email:
[email protected]''
I would think that tighening the muffler bolts when the engine is hot would be my last choice. Use the Blue Loctite when the engine is at room temperature. As the the engine heats after start, the aluminum will expand to a greater degree than the steel bolt causing a more snug fit between the cylinder/muffler and the steel bolt.
I think you might have misunderstood me or I wasn't very clear. I didn't say to use a specific torque value. All I am saying is to take a screwdriver, allen wrench or whatever it happens to be and cinch it down when hot. Re-torquing or re-tightening the bolts when hot on certain assemblies is pretty common and often effective. I've worked on everything from small engines to automotive engines to industrial stuff since the late 80's. One way I learned to prevent exhaust leaks and loose bolts on exhaust manifolds was to get the engine hot, and re-tighten the bolts. Why does it work? I can theorize all day but the bottom line is that it does generally work and that's what matters most. I've found that it works well on RC engines too.
Another thing I've done is put the assembly through several heat/cool cycles then re-torque it. I'm guessing this allows everything to do all it's moving and slight shape tweaking then that final tightening locks it all in place but who knows. Again, it just seems to work.