Rule of 13

My mechanic buddy Richard came over this afternoon to help check the tappets on the Vitesse engine ahead of two day outing to Shelsley Walsh hill climb near Worcester this weekend. The engine is still running in so needs frequent checking. The tappets open and close the inlet and exhaust valves. So setting the right clearances is essential. Back in the day this would have been done every 6,000 miles, but with racing it needs to be done much more frequently to keep engine working at maximum efficiency. Engine needs to be turned over by hand to open each valve in turn and then the clearance of each tappet is checked with a feeler gauge.  Best done as a team of two. A six cylinder engine has 12 tappets. So open valve 1 and check tappet 13-1=12; open valve 2 and check tappet 13-2=11. Only two tappets needed minor adjustment. We are a well honed team   All done in an hour. Thanks Richard