20-12-2020, 09:43 AM
Completely agree with Dave's observation. Ingenious repairs provide much of the satisfaction.
One caution when refacing old valves; presumably the modern replacements are modern materials (non magnetic) which, from experience on other cars, are vastly more resistant to burning than XB and lesser materials of older valves.
3 jaw chucks are not sufficiently concentric and few 4 jaw are free of some wobble.
The stem clarance for Minis etc was inlet .0015 min and exh .002 min. Worth checking before automatically reaming, esp where exh used for inlet. (reamers cut less aggressively if oiled)
One caution when refacing old valves; presumably the modern replacements are modern materials (non magnetic) which, from experience on other cars, are vastly more resistant to burning than XB and lesser materials of older valves.
3 jaw chucks are not sufficiently concentric and few 4 jaw are free of some wobble.
The stem clarance for Minis etc was inlet .0015 min and exh .002 min. Worth checking before automatically reaming, esp where exh used for inlet. (reamers cut less aggressively if oiled)