BOLT-LOCKING 9Y7734 - Caterpillar

1. Preparation of vehicle for wheel horsepower test (consult dynamometer manufacturer's operating instructions for specific details on correct operation). Always perform the Primary Engine Test procedure before vehicle is installed on chassis dynamometer.Calculate the allowable limits that the customer can expect from his engine and present these figures to him.Caterpillar engines are rated with the conditions that follow: Measure and record these variables. Advertised engine bhp (less 3% manufacturing tolerance) can then be corrected to test conditions by use of procedure and correction tables found in Special Instruction GEG01024.a. Place vehicle on the chassis dynamometer. Tie the vehicle in a way that will not add any load to the drive wheels. Do not pull wheels down into dynamometer drive rolls. Check the radiator coolant level, crankcase oil level, tire pressure, tire condition, remove rocks from the tire tread and connect exhaust system.
Recapped tires should be run on a chassis dynamometer only at the customer's own risk.
b. Operate vehicle at 60% of rated speed with moderate load until oil and coolant temperatures reach their normal range for operation. If there is a heavy vibration, drive shaft whip, tire bounce, etc., do not continue with dynamometer test until cause of the problem is corrected. Engines that have had new internal parts installed should be operated on a run-in schedule before operation at full load. For run-in schedule information, make reference to General Instructions section of this Service Manual.2. Put transmission in direct gear and the differential in the highest speed ratio. Operate vehicle at maximum engine speed and increase chassis dynamometer load until a speed of 50 rpm less than rated speed is reached (continuity light should be on). Maintain this speed for one minute and record the engine speed and wheel horsepower. If horsepower is low and poor maintenance is suspected, remove air cleaner or inlet piping to turbocharger and check horsepower again to see if a plugged air cleaner could be the problem.3a. If the wheel horsepower is correct, find the balance point of the engine (speed at which the load stop pin just touches the torque spring or stop bar). At this point the continuity light should flicker (go off and on dimly). If the balance point is correct, then the low power complaint can not be validated. No further test or repairs are necessary.If the balance point is low, see Procedure No. 5.3b. If the wheel horsepower is below the correct value, find the balance point of the engine (speed at which the load stop pin just touches the torque spring or stop bar). At this point the continuity light should flicker (go off and on dimly). If the balance point is correct, see Procedure No. 6.If the balance point is low, see Procedure No. 4.4. Stop the engine. Remove the AFRC (air-fuel ratio control). Put a cover over the hole where the AFRC was installed. Start the engine and check the balance point and horsepower again. If both of these are now correct, the