The auxiliary shaft is mounted in the cylinder block. It drives the distributor (1967-1970 models only), the fuel pump (on carbureted models only) and the oil pump. Whether you're rebuilding an engine or just replacing your timing belt, proper alignment is essential. If the auxiliary shaft lobe is not in the correct position (180 degrees out), the lobe will hit a nut on the #2 connecting rod and cause a nasty engine knock. When the shaft is in the proper position, the pulley marks will align with the belt tensioner spring bolt. Be sure to remember that your Fiat must have the # 4-cylinder at “top-dead center” on the compression stroke. Our Brooklands Fiat 124 Coupe/Spider & 2000 Spider Shop Manual is an excellent source for more information on your Fiat. | 
