i have never changed rings before, but i was looking for new rings online and all the sets i find show 1 upper ring 1 second ring and the oil control rings. for the oil control rings it shows 1 ring and 1 expander. i am in D&R in school and learned than oil control rings are a 3 piece item 2 rings with an expander in between. can anyone explain why i keep seeing this

This is for a f22b1

i plan to do a ring and bearing job. are there any tips and/or tricks i should know before attacking this job.

Is there any suggestions as in to where a good place to get new rings and bearings