If you look in the Triumph Dolomite Range 1976 onwards Parts Catalogue on page 1N 04RUKC1770 it shows two packing pieces. A thick one part number UKC3670 and a very thin one part number UKC1770. I believe that currently all my cars have just the thick spacer fitted but I have had cars fitted with both and I do think I may have a couple of the thin spacers in my box of spare bits. I assume the thinner one would only be fitted as well if there was a noisy engagement of the starter motor to prevent damage to the fly wheel starter ring. Do the experts on this site agree?