Good luck. I've looked into this several times and it seems that for the moment there is no reliable way to make these measurements with wireless technology. Not that it hasn't been tried, its just that the g forces are so great that the transducers don't live. Mahle has a photo in their piston guide of a 2 part linkage that attaches to the piston pin on one end, and the crank case wall on the other. This linkage moves with the piston and gives a path to run wires so they are supported. I don't know a max speed this will survive but it might be worth a try.
It may well be better to attempt measurement of crank torsional stress and make certain deductions. Another consideration might be an optical strain, but high speed triggered viewing could be a challange.
