ST2300 conrod, wrist pin end

[Ed Miller]

Any of you folks out there that have been running ST2300's ever experience a short lived wrist pin end of the con rod ?? I have approximately 100 flights on a ST2300 in a Hanson Dalotel spinning an APC 18x8 with S&W fuels 20% to 30% nitro ( 20% oil in all fuels ) and the bushing in the wrist pin end of the con rod is worn out. I'd say there is at least .030" clearance, maybe more. Engine was down about 700rpm on the ground and never really settled on a rpm and acted lean in the air, in verticals it went flat, would no longer haul plane vertically indefinately. This all happened in maybe 5 or 6 flights, went from a powerhouse to a dog. There is only one small hole in the top of the conrod to lube the wrist pin ( approx .040" in dia. ), the wrist pin is fine and measures no wear at all where the conrod rides on it. I'm going to order a new conrod, if the new one only has one hole in it I may enlarge it a bit as well as add a second hole from the bottom of the wrist pin boss on the rod. Luckily I have a 2nd ST2300, just installed it and I'm back to 8800 rpm on 25% nitro with the 18x8 so I'm ready for the Pocono pattern contest. Both my ST2300's are Italian made, the only notable difference is one has a longer crankshaft ( prop end ).
Thanks...Ed M.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20030623/12ea45a1/attachment.html