The 6.2L damper is made of nodular iron. It is press-fit assembled to the front end of the crankshaft and bolted on. (Figure 2-26).
The function of the torsional damper is to counteract the twisting or torsional vibration caused by force variations on the piston and thus on the crankshaft. Torsional vibration is an oscillation which occurs within every power stroke. The application of force and its removal a split second later causes the crankshaft to be alternately twisted out of alignment and snapped back in place. If a preventive measure is not taken against this action, the engine will run rough and the crankshaft may break.
The damper consists of two parts: A small inertia inner ring, or damper flywheel, and an outer ring. These are bonded together by a rubber insert that is approximately seven mm thick. It is mounted to the front end of the crankshaft. As the engine tends to speed up or slow down, it acts much like a flywheel by imposing a dragging effect due to its inertia. This effect slightly flexes the rubber insert and tends to hold the crankshaft at a constant speed. Thus, it tends to check the twist, untwist or torsional vibration of the crankshaft. This twist might be as much as 10 tons and without a damper, the crankshaft could break.
The vibration damper, like the crankshaft and flywheel, must be properly balanced prior to assembly to the engine.
Since torsional vibration differs with engine design, vibration dampers are designed to suit specific engines.
Also on the outer diameter is a timing groove. We use this groove to statically time the diesel engine during
assembly. This groove can also be used with a mag-tach to measure RPM’s during engine operation. Remove
torsional damper using tool J-23523 and suitable pilot. Install damper using a mallet. Assemble key as shown in
Figure 2-26. Tap damper far enough on crankshaft so attaching bolt may be installed. Torque bolt to specifications
205 N-m (150 ft. lbs.).
