2.25 diesel series 3 land rover chain and skew gear.

well I just got a 2.25 diesel as a project. so far ive had to replace head gasket and heater valve. I have decide to check the chain and sprocket and these are worn to sharks teeth (this vehicle has a serious lack of power and smokey) so not good. how do you go about checking the skew gear on camshaft? because I recon this is probably shot as well. thanks for any help.