Inlet Valve, Cooper S MK II

Inlet Valve, 35.58 mm diameter (1.4″ dia, 3.57″ long)

As it is possible, even common, to swap one head for another on 1275 Mini Cooper engines, it is quite easy to become confused, or worse yet, confuse the parts-guy when it is time to order new valves! Be aware that if the head has been worked on previously, it may have oversized valves or undersized seats. Unless you are 100% sure what is in your cylinder head, it is a good idea to remove a valve for accurate measurement. There are two lengths used (nominally 3.44″ & 3.56″) three different keepers, (wide, narrow, and three-groove) and many different head diameters!