I am replacing the rings on a JD40 tractor. Does anyone know what the proper end gap for the rings should be? My book only says they are sized correctly from the factory and does not give a number. The ones that I am replacing have about .100 gap, which seems way to much to me. They do not seem to have much wear and I think the engine was rebuilt around 1999 from the date on the rod bearings. Everything is standard bore. Thanks.