Flats on Camshaft?

Okay, we'll try this again, the flats are UNDER the valve covers and are machined into the cam so a special tool can clamp down on them to locate them in a certain location. If you are trying this at home, good luck. Anyhow you line the two cams up with flats facing up on front head, then put belt on, unclamp the two cams, rotate crank one turn then retime with the flats facing up on the REAR head. I'm still sorry you have one of these engines. Alternator replacement also a drag.

The camshaft is an apparatus used in piston engines to operate poppet valves. It consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes or cams protruding from it, one for each valve. The cams force the valves open by pressing on the valve, or on some intermediate mechanism, as they rotate.

The relationship between the rotation of the camshaft and the rotation of the crankshaft is of critical importance. Since the valves control the flow of fuel intake and exhaust, they must be opened and closed at the appropriate time during the stroke of the piston. For this reason, the camshaft is connected to the crankshaft either directly, via a gear mechanism, or indirectly via a belt or chain called a timing belt or timing chain. In some designs the camshaft also drives the distributor and the oil and fuel pumps. Also on early fuel injection systems, cams on the camshaft would operate the fuel injectors.

In a two-stroke engine that uses a camshaft, each valve is opened once for each rotation of the crankshaft; in these engines, the camshaft rotates at the same rate as the crankshaft. In a four-stroke engine, the valves are opened only half as often; thus, two full rotations of the crankshaft occur for each rotation of the camshaft.

Depending on the location of the camshaft, the cams operate the valves either directly or through a linkage of pushrods and rockers. Direct operation involves a simpler mechanism and leads to fewer failures, but requires the camshaft to be positioned at the top of the cylinders. In the past when engines were not as reliable as today this was seen as too much bother, but in modern gasoline engines the overhead cam system, where the camshaft is on top of the cylinder head, is quite common. Some engines use one camshaft each for the intake and exhaust valves; such an arrangement is known as a double or dual overhead cam (DOHC), thus, a V engine may have 4 camshafts.

If I remember correctly, the FLATS are located where the bolts for the timing chain gear are located. There you will see on the end of the cam a 3/4 moon shape. The flat spot is used to indicate top dead center and is used to set the timing. Both cams were either with the flat spots up or pointed at each other, i cannot remember for sure and I could be wrong on this. GL!!

It is the very top of the cam lobe.