Volvo/Mack MP8 Rocker Lever Assembly Bolts
The MP8 rocker lever assembly must be torqued correctly to ensure proper valve lash and engine braking operation. Incorrect torque causes valve lash drift and potential valve-to-piston contact. Valve lash must be verified after rocker assembly installation.
Important: These torque specs are reference values. Always verify against your OEM service manual for your specific engine serial number and build date. Torque-to-yield bolts must be replaced — never reused.
Torque Specifications
| Step | Torque Value | Notes |
|---|---|---|
| Rocker Lever Assembly Mounting Bolts | 28 ft-lbs (38 Nm) | Torque in a cross pattern. Verify valve lash after torque. |
| Valve Lash — Intake | 0.016 in (0.40 mm) | Set with engine cold. Verify with feeler gauge. |
| Valve Lash — Exhaust | 0.028 in (0.71 mm) | Set with engine cold. Verify with feeler gauge. |
Related Fault Codes
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Frequently Asked Questions
What is the torque spec for Volvo/Mack MP8 rocker lever assembly bolts?
MP8 rocker lever assembly mounting bolts torque to 28 ft-lbs (38 Nm) in a cross pattern.
What is the valve lash spec for the Volvo/Mack MP8?
MP8 intake valve lash is 0.016 in (0.40 mm) and exhaust valve lash is 0.028 in (0.71 mm), set with the engine cold.
When should MP8 valve lash be checked?
MP8 valve lash should be checked at every major engine service interval and any time the rocker assembly or valve train components are disturbed.
What happens if MP8 valve lash is too tight?
Valve lash that is too tight prevents the valve from fully closing, causing compression loss, misfires, and potential valve burning.