Valve gear wear
"The issue with the valve gear when it comes to maintaining it, it works perfectly well in service but unlike conventional valve gear which is made up of round bushes which get worn and can easily be replaced if they become worn by turning a new set on a lathe. With Joy valve gear is made up of mostly sliding faces like the guide bars which require much more machining work to keep them in the correct condition."
I don't think this is true. There is only one sliding face in Joy valve gear and all the rest are conventional bushes. The Stephenson/Allan/Gooch type valve gear has a link (curved in the case of Stephenson and Gooch gear) that contains a sliding block, that is also susceptible to wear. Edward Harris (talk) 11:42, 8 July 2016 (UTC)