KIT-SWITCH 1986516 - Caterpillar

To make reference easier, the parts charts that follow are a revision of the similar charts in the article "Reference Chart For Main And Connecting Rod Bearings" on Pages 3, 4 and 5 of the November 28, 1977 Service Magazine. These new charts can be used in place of the first two charts (for 60° V-Type engines) in the earlier article. MAIN BEARING INSTALLATION: Selection of the correct main bearings for installation is very important. Installation of the new, longer main bearings with an earlier 9S1994, 9S2303 or 9S8662 Crankshaft that has the larger .299" (7.59 mm) radius on the journals can cause bearing failure. For this reason, the radius of the journals on these crankshafts must be checked. Either of two methods can be used to check the radius of the main bearing journals, as follows: 1. If a Starrett Radius Gauge Kit 178A/178B is available, it can be used as follows: A. Use either the 7/32" (.219"-5.56 mm) or the 15/64" (.234"-5.95 mm) gauge to measure the .226" (5.74 mm) radius.B. Use the 19/64" (.297"-7.54 mm) gauge to measure the .299" (7.59 mm) radius.2. If a radius gauge is not available, a 4B4274 Washer can be used to check the radius as shown in the illustration. This washer has a radius of approximately .250" (6.35 mm), which is larger than the .226" (5.74 mm) radius and smaller than the .299" (7.59 mm) radius. When the washer is held against the crankshaft as shown, contact at two points with clearance between is an indication that the journal has the .226" (5.74 mm) radius. Contact at one point with clearance at both sides of this point is an indication that the journal has the .299" (7.59 mm) radius.
During crankshaft reconditioning, the recommendation is to grind the main bearing journals of earlier 9S1994 Crankshafts (for 12 cylinder engines) and 9S8662 Crankshafts (for 16 cylinder engines) with the new .226" (5.74 mm) radius. The .299" (7.59 mm) radius on earlier 9S2303 Crankshafts (for 8 cylinder engines) must not be changed because these crankshafts are heat treated differently. Be sure to check the journal radius on earlier crankshafts which have been machined to use again.
How to check crankshaft journal radius with a 4B4274 Washer.