See
3H2127EVO for a modern day material and technology chain that is a worthwhile upgrade for use with the tensioner-less stretch lasting much longer and keeping ignition timing correct saving power and petrol consumption making it worth the extra cost.
The Single row timing chain was fitted to every A series engine except the twin row duplex gear set which was introduced on Cooper S cars.
Check your timing gears for wear and if need be replace or alternatively to a duplex kit
C-AJJ3323 or renew original standard single row by ordering
SIMPLEX.
A super chain and tensioner kit are available as
MSSK051EVO.
Please note that the cam gear with the tensioner rings was superseded by the plain gear which is the only type available.