Since our connecting rod was slightly twisted, we decided to order a new one. My dad took care of talking to Ford Racing and Scat about exactly which part to order. That led to an interesting conversation about the piston and connecting rod weight. I weighed the existing rod, and Scat manager to find one that is very close. However, they mentioned that it was important to get the combined weight of the connecting rod and piston assembly within 4 grams of the old weight (preferably with 2 grams).
I was concerned that I couldn’t get an accurate weight from the old piston since I ground some of the damage off and additional wear had occurred on the side of the piston. However, when I flipped the piston over, there was a number written on the bottom that looked like it might be the weight.
I weighed the piston and it was significantly heavier than the number written on the bottom. I figured the weight must be without the piston rings, so I removed as much as I could. There was 2-3″ of the top two rings stop stuck in the piston, but this brought the weight down to 439 grams, so 433.5 grams must be the weight of the bare piston.
While I have the oil pan off, I decided to go ahead and paint it black to match the engine. I spent awhile cleaning out the inside and scuffing the outside with a scotchbrite pad.
