I was digging through some old inventory I have and came accross these rings. Top ring I ***ume is chrome. Second ring is thinner - laterally- and has what I has call and expander ( like some of the early tractors etc). Oil Ring looks normal. It’s a variation of a 4.0-4.030-4.040 Bore. Anyone have some insight on application / and which ring is actually first and /or second.
chrome ring on top. Close up pictures of the end of the rings, might help figure out which way is up. Some have a bevel or notch, some have dots, etc. But taking close up enough pictures is really difficult without the right equipment (a macro lens on an SLR camera, for example)
That will be a challenge that has to be attacked with a piston ring by size and deminsion book laying on the desk with the rings and the calipers. I had to go to the Rock Auto information site and search through a couple of piston rings for the 350 that was in my 71 GMC 2500 but this scan shows the thickness of each ring in the stack. Then when you click on the part number on Rock auto it gives you a vague idea of what the part fits or could fit. It's pretty well ben 34 years since I had my nose in parts books on a daily basis and the rings by bore diameter and then thickness of each ring charts were in the back of the piston ring catalogs. Normally you use that chart when you have a set of pistons and the OEM style piston rings for your engine don't fit those pistons.
My hunch says the ring with the expander is the second ring, the top ring relies on combustion pressure to make the seal.
Yes, top ring would be the one with the plating, and the bevel up. Second ring would have the expander, and have the dot up.
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