Postie... back-end service.

Roddie your careful engine part refurbishments are exemplary...you talk about my favorite reedies of which I hoarded more than 10 the majority having No1 cylinders of which a few are thin wall taper bore oldest stock units. The most aesthetically appealing to me reedies with astonishing performance, proven e.g in my Quickie100, revving near 28k unloaded in the air.

Unfortunately the beryllium star reeds are becoming unobtainium that really inflates the value of your stock. The plastic mylar reeds are thicker and slower and will not support the high rpm-s achievable with the thin beryllium reeds,  in my experience..

I replaced the NV spring on most with a tightly fitting silicone tube ending in a washer on its top end so that when set for max engine power, the NV should stay fixed. The black plastic seal turns brittle over time and will leak air, but the silicone tube sits on it and the NV tight with excellent sealing and vibration damping.

My first encounter with COX exactly 50 years ago was through this engine ending its carrier in a broken Stuka of a privileged friend who got hold of the plane from relatives in Western Germany, with us sitting behind the the then still existing Iron Curtain. He gave me the orphaned engine, which, turning me a COX engine maniac instantly, and a graduated mechanical engineer a few years later,  is still the pride of my collection, sometimes being on duty in my Quickie100 where I often swap engines.

Sorry for my lengthy commentary but the red posty turns me talkative whenever others write posts - with sentiments similar to mine- on it..