from personal experience on 2 occasions -
O-320 but in plank wing.
Engine just off overhaul. Magneto bearing seized. Horrendous screeching, reduction in RPM and then large bang as the idler gear for that magneto failed and it carried on with the remaining mag. This was about 200' on takeoff over a large inhospitable gully. Poked the nose down as trained. After the bang it kept going so self preservation kicked in and carried on for tight circuit over nicer territory to land.
Dropped exhaust valve. As the guides wear the valve when it drops onto the seat does so unevenly. Eventually after this type of battering the head eventually drops off. No big deal you think - there are 3 other cylinders. What they don't tell is that due to the large overlap in the valve timing the broken bits of valve will find their way all the way back through the inlet to the other cylinders. These bits as they bounce around will slowly batter the spark plug gap closed. Lucky to drag it back to the airfield. Dropped valve in this case had also twisted the connecting rod.
I have seen a dropped valve on a R22 push the lower spark plug right out of the cylinder (along with parts of the head). They do not go very well on the remaining 3.
Unless as quoted "water or too much air in the fuel or a dose of carb icing" the Lyco 320 and 360 are pretty tough. The 320 is probably slightly better than the 360 which never runs as smooth.
Last edited by RVDT; 23rd Jun 2011 at 17:39.
Reason: Crap spelling