Measurements of ignition delay (ID) for five fuels: jet-A, three blends of Sasol IPK and jet-A, and a #2 diesel fuel, were performed in a 2.44L heavy-duty single-cylinder diesel engine. A single injection of fuel was used at 5 crank angle degrees before top-dead center (TDC). The in-cylinder conditions at the start of injection were systematically varied over a range of in-cylinder densities from 15 to 40kg/m3 in 5kg/m3 increments. For each density, average in-cylinder temperature was varied over as large of a range as possible by heating the intake air. The range of obtainable temperatures was density dependent, but for each density the temperature was varied from approximately 900–1100K. In-cylinder pressure measurements were performed allowing for ID determination. Methods for in-cylinder temperature determination and ID measurement criteria were tested and compared. The results indicate that the fuel volatility and properties influencing spray breakup have minimal impact on the ignition process. Ignition delay results show good agreement with previous measurements by other investigators performed in a constant volume combustion chamber.