- Jan 18, 2009
- Dunlavin, County Wicklow,Ireland
I inspected an IO-540 that had a prop strike at full power when the undercarriage collapsed on the take-off roll. The blades were bent back like bananas, the prop internals were all smashed and the six mounting bolts were warped and the flange was off-centre. When we got the crank out, the counterweights had damaged the webs to which they were attached. One conrod was slightly bent and slightly twisted. Gear teeth were damaged in the accessory case. The crankcase was damaged but was sent to Lycoming and they repaired it and it flew again.I have been told the non-counter-weighted crankshafts are better as regards prop strikes. Some models of the IO-360 have counter weights and some do not. I bought my Mooney after a prop strike, did the AD and got about 300 hr before I noticed a crack in the "old style case" ....as to weather this was because of the prop strike or not I do not know. I do remember it was not much different than the O-320 inside, the rods had squirt fittings to squirt oil to the opposite cylinder, that the O-320 did not have. The press-fit through bolts were a pain as regard splitting the case in the IO-360 (I jacked them in and out with nuts and a stackup of washers) ....I do not remember that problem with the 67 Cherokee engine. I liked the stretch rod bolts for very accurate torque (measure with a mikecrometer ) on the IO-360. I was lucky as the local flight school let me trade them different size push rods to get the dry-lash right in the middle of the tolerance. Careful of the nut and bolt inside the top of the case when splitting the case.