Hi, I am new to the fourm, I have a 2004 Mini Cooper Base R50 with a burnt exhaust valve in number 4 cylinder. I have removed the head and am ready to take it to my automotive machinest.I would like to replace all the exhaust valves with new ones.Can I put R53 cooper S exhaust valves in the head with out other mods? They are much better quality. Thanks Jeff

 

They should be a direct drop in replacement. Same dimensions, different alloy.
The Cooper S head that they go into as well as the springs, and keepers have the same part numbers as the Cooper head, springs, keepers.

 

I appreciate the information, I was also looking at ULTRIK performance valves and notice they list them to fit R50 and R53 Cooper & S. I think I will stay with stock valve size even though I am opening up the exhaust ports. For the few extra $ I think the inconel R53 valves should outlast the stock R50 valves