Piston Ring Alignment Tool

This tool allows you to align a piston ring instantly in a car's cylinder so that it sits perfectly flat and lets you measure its gap with a feeler gauge. The ring is currently set up for an 87 mm piston (in this case, for the Nissan Z32 engine from a 300ZX), but you can resize the model in software to fit the size of piston you have.

The alignment tool tapers toward the wall of the cylinder and has cutouts so you can see the ring while you're using the tool, to make sure it's aligned properly. It's simple but super-handy!

Print the tool upside-down, so that the part which touches the piston ring is facing up: this will ensure that you get a nice, flat surface without any of the roughness which can come from removing the raft, etc.

See the photos for an explanation of how it works.