1979/09/19 Caterpillar

All 5.4"
Bore 60°
V-Type Engines Except 3400 Series

Description of Change: New main and connecting rod bearings used in the above engines have a thicker layer of surface material for longer service life. In addition, the main bearing journals of the current crankshafts are ground with a smaller radius at each end. The new main bearings are longer, with increased bearing surface area for more load capacity. Other improvements are made to the main bearings, including changes to the bearing curve radius, bearing-to-journal clearance, and a larger oil hole.

Adaptable As: Direct replacement as shown in the chart. New main bearings with the thicker surface material and other improvements are available in the shorter 1.740" (44.20 mm) length for use with earlier 9S1994, 9S2303 and 9S8662 crankshafts that have the .299" (7.59 mm) radius on the main bearing journals. Earlier 9S1994 and 9S8662 Crankshafts can be changed to the new .226" (5.74 mm) radius during crankshaft reconditioning, but 9S2303 Crankshafts must not be changed. See the topic "Main Bearing Installation" for information about how to check earlier crankshaft journals to be sure the correct main bearings are installed.

A plastic pocket size card, Form SEBD0523 "5.4" 60°V Main Bearing Selection Guide", is available as a fast, easy reference for the selection of main bearings. The card has two opposite corners cut to the approximate radii of the earlier and later main bearing jounrals, and can be used as a radius gauge.

The new bearings are in effect on engines with the serial numbers that follow:

NOTE: 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 2, 3 and 4 of the November 30, 1977 Engine News. These new charts can be used in place of the first two charts (for 60°V-Type engines) in the earlier article.

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.

How to check crankshaft journal radius with a 4B4274 Washer.

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.