Most lightweight engines

[Rockerbri]

Cant say Ive ever had that problem, have you had this a lot ???

[Red Gauntlet]

Here is a quick update, I swapped out the big end and here is the rod, it is perfectly straight measured with a CMM so a bit puzzling really, you can see that it has worn badly on the drive side and heated to blue on the timing side. The only thing I can imagine is that the timing side bush had worn and offsetting the crank angle... maybe? This is the 3rd engine to have done this out of 5 that have come to me of varying mileage and capacity. (250/350) once completely rebuilt they appear to be fine.