Further proof that I ain't seen everything yet... HAMBer chstitans42 has a thread going with some great pics of the engine teardown in his '56 Cadillac 365. As a matter of fact the pics are so good that they've raised a mystery for me. There's what appears to be a narrow top ring groove with no ring in it on any of the pistons, so I****ume it's supposed to be that way. Does anybody know what the purpose of this empty top groove is? If it's supposed to be some kind of a "carbon trap" it seems to be working properly! http://www.jalopyjournal.com/forum/showpost.php?p=9342552&postcount=124 It also has what looks like a one-piece oil ring. That's a new one on me too. Would that have been the OE part, or somebody's aftermarket "Whiz Bang" set up to control oil consuption?
I've seen the one piece oil rings before but do not recall ever seeing the narrow, and unused, groove in the piston as pictured. In fact, the groove is so narrow, that a normal ring wouldn't even fit into it. A mystery to me too !
Thanks Hoop98! Looks like you might have gotten that illustration from the Hastings website. Didn't think to look there since they make piston rings and there wasn't any ring in that groove. Gotta learn how to think outside the box more! Reducing heat transfer makes sense though. Kind of like cutting down trees to form a fire-break in a forest fire. At least some of the heat gets rerouted to the inner part of the piston head instead of having a direct route to the top ring land.
The Jalopy Journal
