Usage:
1. Clean engine thoroughly.
2. Remove crossover pipes and other components to gain access to covers.
3. Remove the valve mechanism upper covers.
4. Remove valve mechanism cover base.
Adjustment Reference Point
Number 1 piston at top center (TC) on the compression stroke is the starting point for all timing procedures and is the reference point for all engine valve and engine brake adjustments.
5. Remove timing bolt from its storage area above the left side starter location.
6. Insert the Caterpillar turning tool.
7. Insert timing bolt.
NOTE: There are two threaded holes in the flywheel. These holes are in alignment with the plugged hole in the left front of the flywheel housing. Remove plug. The two holes in the flywheel are at a different distance from the center of the flywheel so the timing bolt cannot be put in the wrong hole.
Next, turn the flywheel counterclockwise (as viewed from the flywheel end of the engine) until the flywheel hole is aligned with the timing bolt. When the timing bolt can be turned freely in the flywheel threaded hole, the engine No. 1 piston is on top center.
Look at the valves of No. 1 cylinder to see if No. 1 piston is on the compression stroke. If No. 1 cylinder is on the compression stroke, the valves will be closed and the rocker arms can be moved up and down by hand.
If No. 1 piston is not on the compression stroke, remove the timing bolt. Turn the flywheel 360 degrees counterclockwise and reinsert the timing bolt.
Adjustment Reference Point. Alternate Method
The following method for locating No. 1 T.D.C. may be used if the flywheel is inaccessible.
1. Remove plug from fuel injection pump housing and install correct timing pin.
2. Slowly rotate crankshaft counterclockwise until pin goes into groove.
| NOTICE |
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DO NOT ATTEMPT TO BAR ENGINE WITH THE TIMING PIN ENGAGED. THE PIN MAY BE SHEARED OFF AND CAUSE ENGINE DAMAGE. |
The engine is now set at No. 1 T.D.C. compression stroke.
3. Make a mark on the engine crankshaft vibration damper and on the front case of engine in line with each other as a reference point for cylinder No. 6 T.D.C. compression.
4. Remove timing pin from fuel pump and replace plug.
Fuel Line And Rocker Arm Removal
1. Remove the fuel lines using the special Caterpillar fuel line wrench.
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THE FUEL LINES AND NOZZLE ASSEMBLIES MUST BE PROTECTED FROM CONTAMINATION. FUEL LINE REMOVAL TAKES PLACE DOWN-STREAM FROM FINAL FILTRATION. |
2. After removing the fuel lines, place them in the plastic bag found in the fuel line protective group. Install the protective caps on the nozzle assemblies. Push the plastic plugs into the open fuel lines.
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COMPLETE ONE ENGINE BRAKE HOUSING INSTALLATION BEFORE STARTING THE INSTALLATION OF THE SECOND HOUSING. THE PRACTICE OF REMOVING SIX ROCKER ARM HEAD BOLTS AT ONE TIME CAN INTERFERE WITH THE PROPER SEATING OF THE ENGINE HEAD. |
3. Loosen the rocker arm adjusting screw locknuts. Remove the rocker arm bolts. Save the washers for use later.
4. Remove the entire rocker arm group. (3 cyl.)
5. Remove the exhaust valve bridges from the engine.
6. Remove the exhaust valve bridge leveling screws and jam nuts from the Caterpillar exhaust valve bridges.
7. Loosely install the Caterpillar exhaust valve bridge leveling screws and nuts into the Jacobs bridges.
Bridge Adjustment
1. Put some clean engine lube oil into the bridge bore. Install the Jacobs Exhaust Valve Bridges on the engine and level them as follows:
a. Back off adjusting screw several turns making sure it is not in contact with the valve stem.
b. Press firmly and straight down on the top of the bridge.
c. Turn the adjusting screw clockwise until contact is made with the valve stem, then turn the adjusting screw an additional 20 to 30 degrees (1/2 flat of locknut).
d. Hold the adjusting screw in this position and tighten the locknut to 24 lbft (32N·m).
e. Put some clean engine lube oil on the area where the rocker arm contacts the bridge.
NOTE: THE INTAKE VALVE BRIDGES MUST ALSO BE ADJUSTED AT THIS TIME USING SAME PROCEDURE.
Exhaust Rocker Adjusting Screw Exchange
1. Remove the slotted head Caterpillar exhaust rocker adjusting screws.
Note the difference between the Caterpillar and Jacobs Rocker Adjusting Screws.
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THE LARGE HEADED C-346B SCREWS CAN BE USED WITH C-346A AND C-346 HOUSINGS. IF C-346B SCREWS ARE USED ON C-346A AND C-346 HOUSINGS, MODEL C-346B MASTER PISTON RETURN SPRINGS MUST ALSO BE USED. SEE PARTS MANUAL FOR PART NUMBERS. |
2. Install the Jacobs rocker adjusting screws in the exhaust rocker levers. Reuse the Caterpillar lock nuts. Discard Caterpillar adjusting screws after substitution.
Extraction Of Dowel Pin
1. Identify the front (fan end) of the rocker arm groups. Tightly clamp the Jacobs special Dowel Pin Extractor or similar tool on the front locating pin of the rocker group. Pin must be extracted at cylinder No. 1 location. Be sure to do the same at the No. 4 location later on.
Carefully extract the dowel pin by tightening the two cap-screws in small equal increments (1/4 turn each).
2. Lubricate the end of the Jacobs oil supply adapter with clean engine oil and install in place of the Caterpillar dowel pin. The pin holes in the pedestal and the rocker arm shaft must align. Do not install "O" ring at this time.
Rocker Arm Reassembly
1. Before installing rocker arms group back on engine, attach a suitable length of tubing to a blow gun nozzle. Blow the oil out of the holddown bolt holes. While blowing the oil out, cover the bolt holes with a clean rag to prevent oil from spraying.
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EYE PROTECTION MUST BE WORN. OIL IN HOLDDOWN BOLT HOLES IS BLOWN OUT TO PREVENT THE ENGINE BLOCK FROM CRACKING DURING THE TORQUING OF JACOBS HOLDDOWN STUD. PERSONAL INJURY CAN RESULT IF SAFETY GLASSES ARE NOT USED. |
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2. Apply clean engine oil to the threads and underside of all Jacobs studs.
Place the rocker arm groups back on the engine. The two outside (end) bolts and washers in each group must be replaced with Jacobs studs and washers. Use the Jacobs washers marked "A" under the head of the Jacobs 3/4" studs. Fit the push tubes to the rocker adjusting screws.
| NOTICE |
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WORK CAREFULLY ON ENGINES WITH GLOW PLUGS. WIRE LEADS CAN BE PUNCTURED IF THEY ARE ALLOWED TO MOVE UNDER THE ROCKER ARM GROUP PEDESTAL. |
3. Make certain that the rocker assembly is centered in the bolt hole clearances. Grasp rocker assembly and move back and forth to assure proper centering. Snug the studs and bolts firmly in the centered position.
Starting with the inner stud and progressing towards either end of the engine, torque to 200 lbft (270N·m) then to 330 lbft (450N·m) in 50 lbft (70N·m) increments.
Installation Of Support Bracket
1. Fig. 2-24 shows the Caterpillar head bolt to be removed for installation of the Jacobs support bracket.
NOTE: Models C-346B and C-346A require one support bracket at the rear position for each engine brake housing. The earlier C-346 uses two support brackets for each engine brake housing.
2. Apply clean engine oil to the threads and underside of head of the bolt and install the Jacobs support bracket. Reuse the Caterpillar washer and head bolt at this location. Center the bracket in the bolt hole clearance and hand tighten.
Brake Housing Installation
For engines with serial numbers lower than 7FB39279 and all 92U prefix engines, the "HOUSING LEVELING PROCEDURE" is required. Refer to pages 18 and 19 for the leveling (shimming) instructions.
NOTE: The following housing installation procedure is for engines with serial number 7FB39279 or higher.
Flow plates on engine brake housings have part number and front or rear housing stamped on plate. Housing marked "front" must be used on the front three cylinders. Housings marked "rear" must be used on rear three cylinders.
1. Install the Jacobs spacers marked "B" on the Jacobs studs.