0320770 JOHNSON CYLINDER HEAD ASSEMBLY

Illustration 1 g06220811The crankshaft can be deflected if the engine was not installed correctly. If the engine mounting rails are not fastened correctly to the foundation mounting rails, the cylinder block can twist or the cylinder block can bend. This will cause the crankshaft to deflect. This deflection can cause crankshaft failure and bearing failure.The crankshaft deflection must be checked after the final installation of the engine. Check the crankshaft deflection when the engine is cold and when the engine is hot. The following procedure can be used to check the crankshaft deflection.
Remove an inspection cover from the cylinder block that will give access to the proper connecting rod journal. On 3612 Engines that drive equipment from the rear of the engine, the following connecting rod journals should be checked: number 5, number 6, number 11, and number 12. On 3612 Engines that drive equipment from the front end of the engine, the following connecting rod journals should be checked: number 5, number 6, number 1, and number 2. On 3616 Engines that drive equipment from the rear of the engine, the following connecting rod journals should be checked: number 7, number 8, number 15, and number 16. On 3616 Engines that drive equipment from the front end of the engine, the following connecting rod journals should be checked: number 7, number 8, number 1, and number 2.
Turn the crankshaft in the direction of normal rotation until the center of the counterweights barely go beyond the connecting rod.
Install a Starrett Crankshaft Distortion Dial Gauge No. 696 with a Starrett No. 696B between the two counterweights. Put the dial indicator within 10 mm (0.39 inch) of the end of the counterweight. Turn the dial of the dial indicator to align the zero with the pointer. Turn the dial indicator on the end points until the pointer of the dial indicator will not move from zero.
Turn the crankshaft in the direction of the normal rotation until the dial indicator almost makes contact with the connecting rod. This connecting rod is on the other side of the crankshaft.Note: Do NOT allow the dial indicator to make contact with the connecting rod.
The dial indicator reading must not change more than the appropriate value that is given in Table 1 for the approximate 300 degrees of crankshaft rotation. Now turn the crankshaft in the opposite direction to the starting position. The dial indicator must now read zero. If the dial indicator does not read zero, do the procedure again.
Table 1
Maximum Acceptable Dial Indicator Readings
Front Cylinders Middle Cylinders Rear Cylinders
0.18 mm (0.007 inch) 0.08 mm (0.003 inch) 0.18 mm (0.007 inch) If the dial indicator reads more than the value that is given in Table 1, the cylinder block is distorted. Loosen the bolts that hold the engine mounting rails to the foundation mounting rails. Adjust the shims to straighten the engine again. Ensure that the engine mounting bolts have enough clearance to allow the engine to expand as the engine gets hot.