# Caterpillar D3500 Valve Lash Adjustment
*<small>This user manual sample outlines the valve lash adjustment procedure for a Caterpillar D3500 engine to make top-end adjustments.</small>*

## Tools
You will need the following tools to adjust valve lash:

- Valve Lash Gauge Group
- Dial Indicator
- Indicator Contact Point
- Wrench
- Torque Wrench
- Bridge Nut Socket
- Gauge Support
- Indicator Contact Point
- Indicator Extension

## Procedure
1. Ensure the number one piston is in the top center position, either Top Center Compression (TCC) or Top Center Exhaust (TCE).
2. Adjust the valves according to the table below.

| Engine | Correct Stroke for #1 Piston at Top Center Position | Inlet Valves | Exhaust Valves | Injectors |
|-----|-----|-----|-----|-----|
| 3508 | Compression | 1-2-5-8 | 1-2-3-7 | 2-3-4-7 |
| 3508 | Exhaust | 3-4-5-7 | 4-5-6-8 | 1-5-6-8 |
| 3512 | Compression | 1-3-6-7-10-12 | 1-4-5-6-9-12 | 2-4-5-8-9-11 |
| 3512 | Exhaust | 2-4-5-8-9-11 | 2-3-7-8-10-11 | 1-3-6-7-10-12 |
| 3516 | Compression | 1-2-5-7-8-12-13-14 | 1-2-3-4-5-6-8-9 | 3-4-6-9-10-5-15-16 |
| 3516 | Exhaust | 3-4-6-9-10-11-15-16 | 7-10-11-12-13-14-15-16 | 1-2-11-7-8-12-13-14 |

3. Install the gauge support with the dial indicator and indicator contact point in the rear bolt hole of the valve cover base.
4. Move the valve rocker assembly up and down several times to remove residual oil.
5. Connect the torque wrench and the bridge nut socket to the wrench.
6. Place the assembled wrench on the rocker arm nut.
7. Apply upward pressure to the front of the rocker assembly.
8. Set the dial indicator to zero.
> Note: Do not apply any torque on the torque wrench. The weight of the torque wrench allows accurate valve lash readings.
9. Loosen the locknut located on the pushrod adjustment screw.
10. Turn the adjustment screw until the valve lash is set to:
Inlet valves: 0.50 +- 0.08 mm (0.020 +- 0.003 inch)
Exhaust valves: 1.00 +- 0.08 mm (0.040 +- 0.003 inch)


Adjustment Screw
*<small>D3500 Master Mechanic Top-End Settings* (Illinois: Caterpillar Inc., 2013), 10.</small>

11. Tighten the adjustment screw nut to the preset torque on the torque wrench: 70 +- 15 Nm (50 +- 11 ft lb).

## Recheck the Adjustment

12. Verify the dial indicator reads the correct value for inlet and outlet valves.
Inlet valves: 0.50 +- 0.08 mm (0.020 +- 0.003 inch)
Exhaust valves: 1.00 +- 0.08 mm (0.040 +- 0.003 inch)
13. Lift up on the torque wrench to remove the lash from the valve. The dial indicator should read 0.000 inches in the raised position.
14. Release the torque wrench and ensure the dial indicator still reads the correct value.
15. Perform additional adjustments if needed.

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#### Reference
*D3500 Master Mechanic Top-End Settings.* Illinois: Caterpillar Inc., 2013.