Here's where I got them: naca.larc.nasa.gov. Have fun digging...
| naca-report-45 | Effect of Compression Ratio, Pressure, Temperature, and Humidity on Power (26 pages) |
| naca-tn-93 | The Background of Detonation (21 pages) |
| naca-report-189 | Relation of Fuel-Air to Engine Performance (16 pages) |
| naca-wr-e-199 | Nitrous Oxide Supercharging of Aircraft Engine-Cylinder (36 pages) |
| naca-wr-e-198 | Effect of Engine-Operating Variables and Internal Coolants on Spark-Advance Requirements of a Liquid-Cooled Cylinder (36 pages) |
| naca-report-205 | The Effect of Changes in Compression Ratio Upon Engine Performance (22 pages) |
| naca-wr-e-264 | Effect of Water-Alcohol Injection and Maximum-Economy Spark Advance on Knock-Limited Performance and Fuel Economy of a Large Air-Cooled Cylinder (13 pages) |
| naca-report-277 | The Comparative Performance of an Aviation Engine at Normal and High Inlet Air Temperatures (19 pages) |
| naca-wr-e-280 | Aerodynamics of the Carburetor Air Scoop and the Engine Cowling of a Single-Engine Torpedo-Bomber-Type Airplane (36 pages) |
| naca-tn-405 | Valve Timing of Engines having Intake Pressures Higher than Exhaust (13 pages) |
| naca-report-426 | The Effect of Humidity on Engine Power at Altitude (7 pages) |
| naca-tn-476 | The Effect on Engine Performance of Change in Jacket-Water Outlet Temperature (12 pages) |
| naca-report-486 | Infrared Radiation from Explosions in a Spark-Ignition Engine (12 pages) |
| naca-report-493 | The Physical Effects of Detonation in a Closed Cylindrical Chamber (19 pages) |
| naca-report-512 | Some Factors Affecting Combustion in an Internal-Combustion Engine (17 pages) |
| naca-report-531 | The Effect of Water Vapor on Flame Velocity in Equivalent CO-O2 Mixtures (6 pages) |
| naca-report-657 | The Influence of Directed Air Flow on Combustion in a Spark-Ignition Engine (14 pages) |
| naca-report-699 | Effect of Fuel-Air Ratio, Inlet Temperature, and Exhaust Pressure on Detonation (25 pages) |
| naca-report-756 | The Induction of Water to the Inlet Air as a Means of Internal Cooling in Aircraft-Engine Cylinders (13 pages) |
| naca-report-757 | The Measurement of Fuel-Air Ratio by Analysis of the Oxidized Exhaust Gas (7 pages) |
| naca-tn-774 | Ionization in the Knock Zone of an Internal-Combustion Engine (19 pages) |
| naca-tn-787 | Factors Affecting Heat Transfer in the Internal Combustion Engine (25 pages) |
| naca-report-812 | Knock-Limited Performance of Several Internal Coolants (13 pages) |
| naca-report-853 | Cylinder-Temperature Correlation of a Single-Cylinder Liquid-Cooled Engine (15 pages) |
| naca-report-855 | Relation Between Spark-Ignition Engine Knock, Detonation Waves, and Autoignition as Shown by High-Speed Photography (27 pages) |
| naca-tn-861 | The Effect of Valve Cooling Upon Maximum Permissible Engine Output as Limited by Knock (21 pages) |
| naca-report-886 | Spark-Timing Control Based on Correlation of Maximum-Economy Spark Timing, Flame-Front Travel, and Cylinder-Pressure Rise (6 pages) |
| naca-report-895 | Analysis of Variation of Piston Temperature with Piston Dimensions and Undercrown Cooling (10 pages) |
| naca-report-897 | Knocking Combustion Observed in a Spark-Ignition Engine with Simultaneous Direct and Shlieren High-Speed Motion Pictures and Pressure Records (19 pages) |
| naca-tm-899 | The Hydrodynamic Theory of Detonation (35 pages) |
| naca-report-931 | Correlation of Cylinder-Head Temperatures and Coolant Heat Rejections of a Multicylinder, Liquid-Cooled Engine of 1710-Cubic-Inch Displacement (24 pages) |
| naca-tn-977 | Development of a Detonation Detector Suitable for Use in Flight (77 pages) |
| naca-tn-1026 | Charts of Thermodynamic Properties of Fluids Encountered in Calculations of Internal Combustion Engine Cycles (35 pages) |
| naca-report-1182 | Comparison of Effectiveness of Convection-, Transpiration-, and Film-Cooling Methods with Air as Coolant (18 pages) |
| naca-tn-1446 | Theory of the Inlet and Exhaust Processes of Internal-Combustion Engines (95 pages) |
| naca-tn-1883 | Thermodynamic Charts for Internal-Combustion-Engine Fluids (24 pages) |
| naca-tn-2025 | Effect of Valve Overlap and Compression Ration on Variation of Measured Performance with Exhaust Pressure of Aircraft Cylinder and on Computed Performance of Compound Power Plant (39 pages) |
| naca-tn-2703 | Electrical Techniques for Compensation of Thermal Time Lag of Thermocouples and Resistance Thermometer Elements (88 pages) |
| naca-rm-e6l05a | Knock-Limited Power Outputs from a CFR Engine Using Internal Coolants (16 pages) |