The diagram shows the valve assembly for the later Series 2 models (from SXC19 & B22CU) and all Series 3 models. Early series 2 models had no valve stem seals and used a different valve guide. Most models have subsequently been modified to the later design used on late series 2 models onwards.
If you have an early Series 2 model that has not been modified please email us for parts relating to your car. An extract from the workshop manual regarding the modification can be read here.