This pin holds the tensioner 12G2628 for cars with single chain timing gears from 1980 onwards.
You can tell if your car has this set up, because the timing cover has a large bulge to accommodate this set up.
Started on engine numbers 99H791 998cc and 10H791 on 1100cc.
Fitted to 998 / 1100cc from 1979 and 1275GT from 1974.
Recommend: 1 x 12G2629 per Mini.
For the timing tensioner plate, see 12G2628
For the timing chain tensioner pad, see 12G2621