Internal combustion engine firing system

A firing system for a multi-cylinder internal combustion engine comprising:

• inlet and exit ports adjacent the top of each cylinder;
• passages interconnecting the inlet port of one cylinder with the exit port of another cylinder;
• a valve in each of said passages;
• and
• means for sequentially opening and closing said valves, said means comprising a cam shaft positioned above a cylinder block of the engine and timing means interconnection said cam shaft with an engine crankshaft positioned below said cylinder block;
• whereby combustion in a first cylinder commences combustion in a second cylinder by the combustion passing from the exit port of the first cylinder through one of said interconnecting passages and valves and through the inlet port of the second cylinder, said engine firing order proceeds sequentially and in a linear fashion from said first cylinder to a last of said cylinders and said system further including a passage and a valve extending between said last cylinder to an inlet port of said first cylinder thus sequentially firing all the cylinders;
• and
• wherein each of said valves comprises:
• a removable first body portion having a side contiguous with said first cylinder and having an entry port in-line with said inlet port;
• a second body portion having a side contiguous with said second cylinder and having an outlet port in-line with said exit port;
• and
• a valve plate arranged to slide in a seat recess formed by said first and second body portions, said plate having a valve port in-line with said entry and outlet ports when said valve is in its open position.