ORIGINAL: 1QwkSport2.5r
ORIGINAL: downunder
Fair enough, I can't see anything wrong with the way you're doing it so the compression should be as you've measured it. It's quite high for a standard engine so it should run very well on zero nitro
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I have my doubts so I will recheck it and do it a little differently. I think what I'll do instead is put the piston at TDC and with the head on fill the chamber with alcohol to the bottom of the glow plug hole. This will be more accurate, I think.
This engine has gobs of power, that is when the carburetor behaves. I think a better carburetor would give it better tractability.
It isnt very often I quote myself.. Anyway I did a recheck of my .20ci car engine and using a much smaller syringe (1cc in .05cc increments) and using oil instead of alcohol or water I got exactly .2cc for the cylinder head only. Water and alcohol have too much surface tension, the oil doesnt.
This equates to .012204ci for the head, and the squish band of .004819ci. Same numbers I posted above. Its for real, as surprising as it is. The little .15 isnt as high, though they market the .20 as "60% more peak power".. I suppose dropping the compression with another shim using the same fuel might give a few more rpm/top end power?
I wish there was a way to stick a prop equivalent to the load of a car's drivetrain to find out what rpm these car engines really hit. I dont know if I trust my Telemetry in my radio and I dont think my prop tach will work on a car engine's flywheel. The crankshaft doesnt have enough of a threaded portion to even stick a 7-8" dia. prop on it.