Engine News

Importance of Proper Valve Lash Setting {1102, 1121, 1123}SMCS - 1102; 1121; 1123

Engine: All 3500 Engines

Correct valve lash settings help provide the following benefits:

Optimum performance

Economical fuel consumption

Contributes to maximizing the service life of related parts

Maintaining rated exhaust emissions

A minor error in the valve lash setting may not cause immediate damage. However, the error willcontribute to reduced performance and fuel economy.

Incorrect valve lash setting can cause the following conditions:

Excessive valve lash causes the valves to seat at higher velocities that can exceed the designcapabilities of the valves, resulting in broken valves.

Insufficient valve lash can prevent the valves from seating. Possible results are burnt valves andcontact of the valves with pistons.

Insufficient exhaust valve lash opens the valve prior to completion of the power stroke. Some of thecombustion occurs in the exhaust system instead of the combustion chamber. Cylinder pressure isreduced, resulting in a loss of power and boost.

Because of reduced power and boost, the operator may increase the throttle, which increases fuelconsumption in order to do the same amount of work.

Inspect the valve lash and adjust the valve lash according to the Operation and Maintenance Manual,"Maintenance Interval Schedule".

For instructions for measuring the valve lash and setting the valve lash, refer to the engine Testing andAdjusting.

Media Number -SEBD9816-00 Publication Date -04/10/2012 Date Updated -04/10/2012

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Thu May 7 15:30:52 UTC-0400 2015

Pgina 1 de 1

07/05/2015

Valve recession occurs normally due to engine operation. Valve recession decreases the valve lash setting,which makes initial and regular scheduled maintenance of the setting necessary.