OT- rings rotate in bores?

Yep. Sombebody did a visible-engine camera once to prove it. The rule about lining up ring gaps 'just so' on installation is pretty much a JC manuever. Even so everyone still does it. Whatever gets ya through the night....

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

They do if they're not stuck from varnish.

It has happened, but it's rare.

Hell, you can see the effects on a vacuum gauge, so yes, it's enough to be noticed.

Here we go again.... JR Dweller in the cellar

patrick mitchel wrote:

This was a question that must have caused Algernon Fortescue-Penberthy many a sleepless night before for he came up with the solution he fitted to his swansong:

The Fortescue-Penberthy 12-85 MKII. A motorcycle for discerning gentleman of the 1930s..

His solution was to machine teeth in the inner diameter of the piston ring, and with spur gears, driven via a ratchet activated by the oscillation of the connecting rod to the piston, providing the means of rotating the rings. The use of composite rings of the Hempworth-Owens type, overcame the expansion and ring gap problems, a conventional ring would have posed. Use of long addendum teeth was used to overcome radial expansion. That the Fortescue-Penberthy family had long been the British importers of Philip-Batek watches was well utilised by Algernon as he made good use of the parts bins in the store. The final variant that successfully went into production, had gearing that resulted in ring rotation of 1.2 rpm + or - 2.27 seconds per week, at a given engine speed of 3,500 rpm. The Greenwich Observatory certifying the accuracy.

The motorcycle was ultimately withdrawn from the market, due to watchmakers picketing local Fortescue-Penbethy dealers, disputing the agents rights to service the engines. The owner's manual called for a clean and adjust monthly..

Tom

Yes. By design.... not by error.

At least one auto manufacturer, I believe Hudson, at one time pinned the ring gaps in line. I remember the instructions to hone the vertical ridge out when installing new rings. I have no idea what the purpose was. Preventing rotation might have been thought to improve sealing and/or life but I see no purpose for gaps in line.

Don Young

It depends: If they are supposed to rotate they don't. If they are not supposed to rotate they do. HTH.

No hudson I've ever seen had the gaps lined up. There were a few engines back in the 20's and 30's that DID have pinned rings though (cannot remember which ones)