Thread: Discussion norvel .074 break in
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Old Oct 03, 2012, 10:46 AM
Dave Campbell is offline
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United States, MI, Commerce Charter Township
Joined Dec 2000
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These engines are notorious for being both very tight at TDC and wearing like iron during break in. This is bad because the first runs ideally need the cylinder warmed with a hot air gun before cranking to prevent crank damage. Even after 2 seasons of flying, mine will still lock solid at TDC because the pinch is still that tight..... I am turning an APC 6.3-4 at about 16,500 on 30%, which is about 1k short of what the guys on RCU say I should get when the engine is worn in. Apparently, the .074's just decide to 'wake up' one day and make good power, but I haven't seen it yet. I have like, 9, of these engines and am hoping that they don't all go this long to being run in.... All that said, I am very happy with the power and performance of the one I am flying.

12k tells me something is wrong with your motor. I'd suspect a bent rod, an air leak, or a tight fit on the crankshaft fit.
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