There is an all too common cause (read stupid mechanics) of low power output. In the following described instance, you will get close to rated static RPM, but low climb rates and slow cruise.
The cause here, and this is an extreme analysis, but I have seen it in several planes (one that made it to TBO actually, with sucky power) is , believe it or not.....
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.THE CAMSHAFT/CRANKSHAFT TIMING IS OFF ONE TOOTH!!!!!!!
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. Yes ladies and gentlemen, this happens, continues to happen and your engine will run and start just fine with this condition. Performance, well that is another story. First my personal history with this, then how to easily see if you are a suffering from this problem.
In my Kitfox, when I built it, in my LYC IO-290, I paid a "reputable" engine builder based out of Lantana airport in Lantana Fl. to put together the bottom end, and he did just that to me.(among many other really bad things, don't get me started)...(PM me for the name of this, umm "mechanic", if you already don't know who it is. STAY AWAY!!!) My flying symptoms were....700 instead of 1100 fpm.....Normal static RPM as expected....Cruise was 122 instead of the expected 135...I tried several props, same thing....
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Now, easy analysis of this anamoly.....Pull a valve cover off of any cylinder....Pull out spark plug and put piston to TDC of the of exhaust stroke(Look into SP hole to hit TDC, or use timing wheel,..whatever...)..... Rock piston back and forth at TDC.Now, note the exhaust valve and intake valve ( actually note the rockers...) at exactly TDC in this position, the ex. valve should close and the intake should open. ....I am not sure if hydrolic lifters will be exactly like solid lifters at this point....Anybody add here???? Rocking the piston back and forth, with the prop in your hand, will show if you are timed correctly...
I certainly hope this is not it, or the engine will soon be coming off to fix...Just another idea for head scratching/hangar flying....
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Bottom line here, your climb performance will obviously be more degraded than cruise, since it takes a whole lot of HP to get a little more MPH.
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.PS, one mechanic said in his humble observation, this happens in at least one out out of 1000 rebuilds. He said he even heard of an engine coming factory new from LYC. in this condition......Also, how much power you lose, depends on whether you are advanced or retarded one tooth........
Glen