318 refresh

I use an OLD ridge reamer. Made much better than the newer type. If you are slow and take your time it does a good job. Honestly, it's really not necessary if you use the same pistons, as the rings will have the same travel. It's only when you replace the pistons and there's a possibility that the ring pack may ride higher in the bore that you really need to remove the ridge. Otherwise, the rings ride in the same place.