[MXTex]

If I understand correctly; when the motor let go on the dyno, the crankshaft and two connecting rods were damaged. If/when this motor gets disassembled (which I think is inevitable), I'd recommend looking very closely at the pistons that were on the connecting rods that were damaged on motor #1. A failed connecting rod could apply some very strong and abnormal forces on a piston. Assuming that the piston locations from motor #1 were duplicated in motor #2, I'd look very closely at these two holes. Do we know which cylinder numbers received the replacement connecting rods? If so, what are the compression numbers for these holes? If one of the cylinders that received the replacement connecting rods has vastly differing compression than the other 7 holes, I think we're looking at piston damage from the original scatter as the root cause.

[Pronto Poncho]

Originally Posted by MXTex

If I understand correctly; when the motor let go on the dyno, the crankshaft and two connecting rods were damaged. If/when this motor gets disassembled (which I think is inevitable), I'd recommend looking very closely at the pistons that were on the connecting rods that were damaged on motor #1. A failed connecting rod could apply some very strong and abnormal forces on a piston. Assuming that the piston locations from motor #1 were duplicated in motor #2, I'd look very closely at these two holes. Do we know which cylinder numbers received the replacement connecting rods? If so, what are the compression numbers for these holes? If one of the cylinders that received the replacement connecting rods has vastly differing compression than the other 7 holes, I think we're looking at piston damage from the original scatter as the root cause.

Thanks, Very insightful about the Pistons. We had the same discussion and wondered if there was piston and cylinder damage. A thorough compression check was made. All cylinders were within 5 lbs or less of each other.

As far as voltage is concerned. Two separate ignition systems were used with the same results. On one of the test a 12 V direct feed was run directly to the coil.

[MXTex]

Originally Posted by MXTex

If I understand correctly; when the motor let go on the dyno, the crankshaft and two connecting rods were damaged. If/when this motor gets disassembled (which I think is inevitable), I'd recommend looking very closely at the pistons that were on the connecting rods that were damaged on motor #1. A failed connecting rod could apply some very strong and abnormal forces on a piston. Assuming that the piston locations from motor #1 were duplicated in motor #2, I'd look very closely at these two holes.