🔍 Key Concepts
• four-stroke diesel cycle (intake, compression, power, exhaust and 180° crank rotation per stroke)
• firing order and crankshaft angle (720° per full cycle, 90° between firing events on an 8‑cylinder 4‑stroke engine)
• relationship between a cylinder’s firing TDC and its position at some number of degrees later in the cycle
💭 Think About
• First, note that there are 8 cylinders in a 4‑stroke engine, so how many degrees of crankshaft rotation are there between each firing in the order 1‑5‑2‑6‑8‑4‑7‑3?
• Figure out how many firing "steps" separate cylinder #2 and cylinder #4 in the firing order, and convert that to crankshaft degrees.
• Starting from #4 at its own firing TDC, walk through its power, exhaust, intake, and compression strokes in 180° steps until you reach the crank angle you found, then identify which stroke #4 must be on.
✅ Before You Answer
• Confirm you are using 720° per full 4‑stroke cycle per cylinder, not 360°.
• Verify that you multiply the number of firing-order steps between #2 and #4 by degrees per firing to get the correct crank angle difference.
• Carefully track the sequence of #4’s strokes starting at its firing TDC: power → exhaust → intake → compression, each covering 180° of crank rotation.