The crankshaft gear wheel and the camshaft gear wheel teeth should also be checked for wear and tear with each tooth approximated by an inverted 'V' shape and touching the periphery of the gear wheel. When so worn, a side of each tooth in tension will be slightly concave in cross-section relative to the side on compression. Any indication of wear means that the gearwheels have to be replaced. Also, find the links of the chain for side slackness and if there is any amount of slackness found it should be replaceable with a new chain. In any case, it is recommended to replace the chain every 30000 ml or earlier if the engine receives a major rebuild, since the rollers on the chain may be slightly grooved if it is geared.