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In 1997 when I first began building my CH601 HDS tail wheel airplane the hot engine to use was the EA-81 Subaru. So I obtained one of these engines. I was also told by many that an Lycoming 0235 would be way too heavy. So installed the Subie. Engine has ran well for over 7 years but has had problems with keeping rings in it. Keep loosing compression, replaced rings 2 twice after the intical rebuild. Also had heads rebuilt by Ram. Engine also ran hot in the 220 range. I think this is why the rings woulod not hold up. about 18 mounths ago the engine was running low on power. So instead of putting new rings and maybe a new bore job I decided an attempt an install of a Lycoming 0235 108 hp C2C.
I reweighed the airplane and discovered it had gained 25 lbs just by adding things to get the Subie to run cooler. I than removed the Subie and all the related items, the weight of the Subie firewall forward was 317 lbs. This floored me. I was very confendendt that i could install thye Lyc at the same or less weight.. Made a new motor mount, made a new cowl out of carbon fiber that saved 10 lbs over the ogrinal cowl. made aircleaner housing of carbon fiber, Installed lite weight starter and, alternator and paid attention to every other thing where i thought weight could be saved. Made new cushions for seats using lighter foam. Well it has all paid off. The empty weight is 27 lbs lighter with the Lyc installed. (used digital scales from aviation collage).
With the Subie when it was running strong my best cruise was about 120 to 125 IAS. Climb out was 600 FPM, Somtimes on cool day I would see 1000FPM but not for extened time.
First flight with the Lyc last evening, 90 deg OAT with 7200 density altitude after airporne climbed out at 80 - 85 IAS at 1000FPM, leveled off at cruise IAS bouncing 135 to 140 (very rough air). Oil temp was a little high at 205 so will install an oil cooler. Max RPM was 2450, so after veryifying tachometer am thinking of getting prop repitched (currently 68x55).
Bottom line is the Lyc out performs the Subie, but the Subie provided 7 years of cheap flying. The Lyc cost considerable more to install than the Subie did.
I am extreamly happy with all the hard work it took to install the Lyc.