Rod stretch

So does anyone know how much alum plate and forged rods can stretch before breaking.

 

Look in machinerys hand book for the materials' elongation percentage than subtract fatigue cycles to failure. Factor in temperature
If you are just looking for stretch, its load divided by( area times youngs modulus)

 

Or you can take the lazy way out and send it to the manufacture to let them put it back in there jig and see if it's really stretched. Why don't you just clay check the top of the piston to head. I've seen some piston with wrong angle valve reliefs and the knuckle just kiss the head.

 

Mine just tapped the flat area outside the dome. did not pinch any rings or collapse any skirts.