One important thing to keep in mind when buying an O-200 is how many times the crank has been ground. ?There is a limit of two grinds at .010" each. ?I had an engine that already had the crank ground twice and had a worn crank that was giving low oil pressure due to the excessive bearing clearance. ?If it had another grind left it would have been something like $500 for a magnaflux, grind, and new bearings, but since it had been ground twice it required a new crank for over $2,000. ?(going on my best memory of prices several years ago, might be off, but you get the idea) ?Used cranks that are serviceable are hard to come by and expensive on the O-200 since new cranks are not available for the C-85 and lots of the remaining O-200 cranks are used up in C-85 to O-200 conversions.
That also brings up another very good option of using a C-85 with the O-200 crank. ?That makes and engine with the power of the O-200, but the weight of the C-85. --------------------------- The costs have gone up a bit. ?Last time I checked a new O-200 crank was up to $3300. Regrinding, nitriding, cad plating the flange, and new bearings runs somewhere around $700 - $750. The -.020 bearing set is kind of pricey as well if you're down to the last grind. ? One thing to remember about using the C-85 as the core to build an O-200 is that you would also want to change the camshaft to make the same HP as an O-200. ?The C-85 cam has a shorter duration and is designed for a lower RPM than the O-200 cam. ?I flew my KR behind a stock C-85 for it's first 350 hours. ?It's a good engine. ?With the O-200 crank and pistons, it does produce more torque and is a desirable upgrade to the C-85, but unless you change the cam, it's not quite the same thing. Craig's O-200 is a great candidate for a Cub, Champ, or T-craft project as the -8 non-electric version of the engine is highly desirable for those planes. ?However, it is not a desirable engine for the KRs due to the lack of electrics. ?The Lycoming ring gear and starter are a work around that could be implemented, but the engine really isn't configured to mount the starter up front and the prop bushings should be swapped out for a longer set of bushings to support the ring gear if they are available. ?Hand propping a KR can be done, but is less than ideal due to the short stature of the KR, which leaves you bending over into the prop when it starts. ?I have propped mine a number of times when the battery was down. ?Even though I have owned a number of hand propped planes and have twisted props on just about every GA engine out there, I am really uncomfortable propping the KR due to the reason cited above. -Jeff Scott Los Alamos, NM
