Final answer:
The engine camshaft can be located in two basic positions: the in-block position, where it operates valves via pushrods and rocker arms, and the overhead cam position, which allows more precise valve timing and better engine performance.
Step-by-step explanation:
The two basic locations for an engine camshaft are the in-block (or OHV, overhead valve) position and the overhead cam (OHC) position. In the in-block configuration, the camshaft is located within the engine block and operates the valves via a series of pushrods and rocker arms. This setup is common in older and some high-torque engines, where durability and simplicity are prioritized.
In contrast, the overhead cam configuration situates the camshaft(s) above the cylinder heads, directly actuating the valves without the use of pushrods. This design allows for more precise timing, can accommodate more valves per cylinder, and often results in better airflow and higher engine performance. Overhead cam systems can be further classified into single overhead cam (SOHC), which has one camshaft per cylinder head, and double overhead cam (DOHC), which has two camshafts per cylinder head to separately control intake and exhaust valves.
As automotive technology evolves, preference has increasingly shifted towards the OHC design for its performance advantages. However, both types of camshaft locations are relevant depending on the specific engine design and intended application.