TAPERED ROD PIN BORE MANDREL
Our aftermarket pistons for a LS7 Chevrolet came with SBC .927” pins. The standard LS7 pin is .925”. There is meat in the bushing to hone, but the problem is the shape of the small end of the rod and bushing. They are tapered. It looked like you couldn’t just hone like a regular bushing, and we had no special mandrel to hold the rods. It seemed like too much might come off the thin top part of bushing or the bushing would get bell-mouthed. So we made a sleeve to the fit big end of the rods by turning a tube down to the rod housing bore diameter. We shimmed with differential shims so two rods would stay straight and stable. The small end is wider than the big end, so they needed to be shimmed apart. We kept the small ends just touching. They were easy to hone to size now, in pairs.
Mike Schmelzer
Bay Speed Center
February, 2018