Noise?
 

Hey Bill, Happy New Year, have a older 52-4C hand me down, it was gumed up,pulled back plate and plug,cam cover and vc. Soaked in trans oil for a week, All loose now,cleaned it out and lightly oiled it. Comp. feels good fueled it up with Gloplugboy 24% Nitro,17% Castor,59%Meth.,flip,flip,flip and it started,very cold here,so i let it idle for a while,at half throt. there is a rude snappin noise. I'm swinging a 12x5 wood zinger. To much prop?,to much nitro?,detonation? Any thoughts?:confused:

You have too much nitro in the fuel. It will run best with about 10%-15% nitro in the fuel. The noise you are hearing is likely detonation. When the engine is set up correctly, you will want it to run in the high-9,000's at full throttle on the ground when leaned to just rich of peak RPM.

Hey Bill, Thanks alot! Been an auto tech for years, I guess thats what detonation sounds like with valves only a few mm's in diam. Thought I screwed the pooch. But like we say at work,"It ran when it got here", thanks again!:)

Love those old ones! 15 years or so,stuck solid.Now in my Mambo.http://www.rcuniverse.com/forum/atta...mentid=2059983

Some of those older engines were of very high quality and will seem to last forever when properly-run and taken care of.