Pietenpol-List: Continental A65 to A75 (was GN-1)
Posted: Thu Aug 26, 2010 7:50 am
Original Posted By: Oscar Zuniga
Ler wrote:>Don's dream Machines' out in GA.. is overhauling an A65-8I'll use this as a launching pad to address a previous emailabout the GN-1 with a Continental that had up exhaust on it.There were three variants of the A50 that had up exhaust: the-1, -2, and -3. Not likely to see many of those around. Mostlikely it was one of the A65 variants that had up exhaust: the-1, -3, or -6. The -1 had single ignition... not likely tosee many of those. The -6 had a starter. If you find one, keep it... they're worth their weight in platinum. Same withthe A65-9, down exhaust with starter. Rare. There were alsovariants of the A75 and A80 with up exhaust, the -3 and -6,but it's most likely that the airplane in the photo has an upexhaust variant of the A65 on it.>he did mention that he put the bigger piston pinsThe Continental factory A75 actually has *smaller* diameterpiston pins than the A65... 0.859", compared to 0.920" for the A65.>(but not the 75 pistons)The A65 and A75 both have 3-ring pistons and are the same bore,Unless it was a very early 4-ring A65 piston. The only differencesbetween the A65 and A75 pistons is the diameter of the wristpins and the fact that the A75 pistons have a waffle face onthe underside to provide better cooling.>drilled something (rod's)Yes, the rods on the A75 have 1/16" holes drilled in the connectingrod caps for better lubrication.>He thinks it's safe to run at higher rpm by getting smaller prop>as an "experimental" if I desire to do soMaybe so. The one other main thing that the A75 has that the A65doesn't are stellite-faced valves and a larger carb venturi.>me thinks me wants to play it safe and get a 72x42 pitch.Probably the better approach but it sounds like your engine willbe most of the way converted to a 75 as an experimental.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net ________________________________________________________________________________
Ler wrote:>Don's dream Machines' out in GA.. is overhauling an A65-8I'll use this as a launching pad to address a previous emailabout the GN-1 with a Continental that had up exhaust on it.There were three variants of the A50 that had up exhaust: the-1, -2, and -3. Not likely to see many of those around. Mostlikely it was one of the A65 variants that had up exhaust: the-1, -3, or -6. The -1 had single ignition... not likely tosee many of those. The -6 had a starter. If you find one, keep it... they're worth their weight in platinum. Same withthe A65-9, down exhaust with starter. Rare. There were alsovariants of the A75 and A80 with up exhaust, the -3 and -6,but it's most likely that the airplane in the photo has an upexhaust variant of the A65 on it.>he did mention that he put the bigger piston pinsThe Continental factory A75 actually has *smaller* diameterpiston pins than the A65... 0.859", compared to 0.920" for the A65.>(but not the 75 pistons)The A65 and A75 both have 3-ring pistons and are the same bore,Unless it was a very early 4-ring A65 piston. The only differencesbetween the A65 and A75 pistons is the diameter of the wristpins and the fact that the A75 pistons have a waffle face onthe underside to provide better cooling.>drilled something (rod's)Yes, the rods on the A75 have 1/16" holes drilled in the connectingrod caps for better lubrication.>He thinks it's safe to run at higher rpm by getting smaller prop>as an "experimental" if I desire to do soMaybe so. The one other main thing that the A75 has that the A65doesn't are stellite-faced valves and a larger carb venturi.>me thinks me wants to play it safe and get a 72x42 pitch.Probably the better approach but it sounds like your engine willbe most of the way converted to a 75 as an experimental.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net ________________________________________________________________________________
