The overhaul of the octane testing machine is recommended to be carried out by the manufacturer’s engineers or trained personnel. Unauthorized overhaul of the octane engine by other personnel may cause damage to the machine, thus affecting the quality assurance of the octane testing machine. Please refer to the operation and maintenance manual provided by the manufacturer for detailed overhaul procedures and details.
The brief process of octane testing machine overhaul, referring to ASTM D2699 and D2700.
Disassemble the complete cylinder/clamping sleeve assembly from the octane engine crankcase. Components to be removed include: detonation pickup, spark plug, all thermometers and temperature sensors, C.R. gearmotor assembly, dial indicator, all intake air system components, the carburetor, cooling water lines, exhaust system components, coolant condenser assembly, cylinder and clamping sleeve assembly and piston.
Separate the cylinder from the clamping sleeve.
Disassemble the valve tapers, retainer and rotator assembly, springs, and valves from the cylinder. Remove the roll pin from the intake valve stem to remove this valve.
Component Cleaning: All combustion deposits, gasket material, rust, and so forth should be removed from components.
Cylinder: Check the cylinder bore diameter. Replace the cylinder if the internal diameter at the area of maximum wear is more than 0.006 in. larger than the unworn skirt internal diameter.
Valves: Check valves. Replace a valve if stem is badly scuffed or stem diameter is less than the replacement limit.
Rocker Arm Assembly: Inspect each component, and replace any worn or out of specification parts.
Piston and Rings: Replace the piston if there is evidence of scoring or a wear pattern. Replacement of all rings at the time of every overhaul is typical. Ring gaps and ring-to-land clearances should be checked.
Clamping Sleeve: Check that the internal bore and counterbore of the sleeve is within tolerance. Inspect the worm shaft ball and thrust bearings and replace as required.
Cylinder Guide Plate: Inspect the wear surface that contacts the worm wheel. Replace the guide plate if there is wear or scoring.
Condenser and Cooling System: Inspect the inner surfaces of the condenser and the baffle tube for rust. Inspect the cooling coil, clean surface deposits and coolant system.
Reassembly Procedures: Follow the operation manual of octane testing engine.
Crankcase Oil Change: Drain the used oil and add new SAE 30 Grade engine crankcase oil.
The octane testing machine needs a trial run for octane rating after an overhaul to check for problems.