1995/01/01 Caterpillar

Electronic Timing Advance Improvements{1272,1253,1264}

Usage:

3406B (8TC, 2EK),
3406C (4CK) Truck Engines

Numerous improvements have been made to the electronic timing advance components on these truck engines. The Steps that follow provide a way to check the electronic timing advance components to determine if the latest components and improvements are incorporated. Use the chart to determine which Steps apply to your engine.

NOTE:

* Steps 1 through 3 can be performed without removing the cover.

* Steps 4 through 7 require removing the cover.

* Step 8 requires the disassembling the timing advance.

* Step 9 requires removing the governor if the gasket is leaking.

1. Check solenoid (BTM) arm. See Illustration 1, Item 1.

* Check arm to shaft joint for damage.

* Check the solenoid part number. The former 9X-6770 Solenoid has been replaced by the new 105-2939 Solenoid. The new solenoid has a stronger shaft. This change is effective with S/N 4CK2537.

2. Check control group (timing sensor) for a loose tip. See Illustration 1, Item 2.

* Check for loose tip.

* Put 9S-3263 Thread Lock of the threads of the 9X-9555 Control Group (timing sensor) before it is installed. This change is effective with S/N 4CK6001.

* The 118-7204 Sensor Tip Kit is available for repairing or replacing the sensor tip.

3. Check to be sure the bellcrank is in the correct position. See Illustrations 1 and 2, Item 3 and Illustration 3, Items 5 and 6.

* Check the thrust bearing face and the front of the 2W-3635 Sleeve for wear caused by the bellcrank being out of position with respect to the thrust bearing.

4. Check bellcrank assembly to be sure pin (4) is correctly installed. See Illustrations 1 and 2, Items 3 and 4.

* Check the faces of the bellcrank to be sure that no excessive wear has occurred.

* Check round area of the bellcrank to be sure the spring is not causing galling of the bellcrank on the pivot pin.

* The 2W-3623 Bellcrank Assembly pin depth is correct effective with S/N 4CK11473.

* Bellcrank end play should be .13 to .64 mm (.005 to .025 in).

5. Check spool in fuel pump and governor drive group. See Illustration 3, Item 7.

* Check spool for damage and part number.

* Replace former 4W-2750 or 7E-5564 Spool with new 4P-3384 Spool. The new spool is effective with S/N 8TC13234.

6. Check eight bolts (8) in fuel pump and governor drive group. See Illustration 3, Item 8.

* Check to be sure 6J-2819 Bolts (8) are used.

* Tighten the 6J-2819 Bolts to a torque of 16 N·m (12.0 lb ft). The new longer bolts and higher tightening torque are effective with S/N 2EK1823.

7. Check to be sure the former 3P-3547 Retaining Ring has been replaced by the new 108-4511 Clamp Assemlby. See Illustration 3, Item 9.

8. Check to be sure the plug is in position in the carrier assembly. See Illustration 3, Item 10. (New threaded plug used with 101-1944 Carrier Assembly shown.)

* New 101-1944 Carrier Assembly with threaded plug effective with S/N 4CK4699.

* Do NOT use former 0T0200 Cup Plug.

9. Check for oil leak between governor and fuel injection pump housing. See Illustration 4, Item X.

* Oil leak can be internal or external.

* Oil leaking past 4W-2491 Gasket.

* New tightening specification for 8S-4710 Bolt (11) is 16 ± 4 N·m (12 ± 3 lb ft) and is effective with S/N 4CK15840.

Illustration 1. Timing Control Group components. Solenoid (1). Control Group (2). Bellcrank Assembly (3). Pin (4).

Illustration 2. (View A-A) Timing Control Group components. Bellcrank Assembly (3). Pin (4).

Illustration 3. Governor And Fuel Pump Drive Group components. 2W-3635 Sleeve Assembly (5). Thrust bearing (6). 4P-3384 Spool (7). 6J-2819 Bolts (8). 108-4511 Clamp Assembly (9). 101-1942 Plug in 101-1944 Carrier Assembly (10).