11. Preferred stock in shock absorber and piston ring maker Cia. 12. Piston ring failures and cylinder head sealing problems were experienced during early flight testing.13. Three rather than four piston rings were fitted, and the engine balancing was improved. 14. These have Teflon piston rings , molybdenum cylinders, low-friction coefficient materials. 15. Gas sealing is achieved by the use of piston rings . 16. Most piston rings are made of a very hard and somewhat brittle cast iron. 17. For compression, the pistons have two piston rings which slots are cast into the piston. 18. Piston ring design has been identified as a problem.19. Piston rings are not perfect seals : each has a gap to allow for expansion.20. Hope said the decision was " bizarre " because Kolbenschmidt does not make piston rings .
