New Turbochargers Are Now Used on Certain 793C, 793D, 793B, and 789C Off-Highway Truck Engines {1052} Caterpillar

Engine

3516B (S/N: 8WM1-3441)

Off-Highway Truck/Tractor

789C (S/N: 2BW1-2128)

793B (S/N: 1HL1-524)

793C (S/N: CBR1-108; 4AR1-424; ATY1-1124; 4GZ1-264)

793D (S/N: FDB1-1946)

Description Of Change:

Note: The change impacts low altitude 793D trucks, 793B or 793C trucks if equipped with High Displacement (HD) retrofit engines, and High Altitude Arrangement (HAA) 789C trucks.

The new turbocharger groups have a more robust joint between the turbine housing and center cartridge. Improvements were made to the turbine housing V-band clamp, center cartridge, and turbine housing.

Note: There is no performance difference between the new and former turbochargers, so there is no concern with them being mixed on an engine.

Illustration 1	g06254868
(1) Cartridge (2) Turbine housing v-band (3) Turbine housing

Adaptable To: The following changes are adaptable to the products within the listed serial numbers, and are effective with all products after the listed serial numbers.

Refer to Table 1, Table 2 and Table 3 for a list of required parts for the appropriate application.

Note: It is not recommended to mix and match any of the new and former turbocharger components listed in Table 1, Table 2 or Table 3.

Illustration 2	g06254883
V-band section view

The new V-band clamp has both a thicker and wider V-band, along with a larger T-bolt. This clamp requires an increased torque compared with the former design.

The new turbine housing has extra material removed to allow more clearance for the wider V-band clamp.

Illustration 3	g06254936
Center housing cross section (4) Increased length of pilot

The length of the pilot of the new center housing, which supports the turbine housing, has been increased. Refer to Illustration 2.

New Turbine Housing V-Band Clamp Torque Procedure

Note: The v-band clamp is considered a one time use only component and should be replaced if needed.

Note: Do not retighten the v-band clamp after the engine has run.

Note: Limit the run down speed of the nut for the v-band clamp to 60 rpm maximum to avoid galling the threads.

1. Apply Loctite^® C5A Anti-Seize to the threads of the clamp.

2. Tighten the turbine housing v-band clamp to 20 N·m (15 lb ft).

3. Tap lightly around the entire circumference of the clamp with a soft-faced hammer.

4. Tighten the clamp to 30 ± 2 N·m (22 ± 1.5 lb ft).

5. Tap lightly around the entire circumference of the clamp with a soft-faced hammer.

6. Tighten the clamp to 30 ± 2 N·m (22 ± 1.5 lb ft).