Engine Builders: The AERA Technical Committee offers the following information for head gasket selection for Toro Groundmaster and Roadmaster units with 1982-’99 Peugeot XUD9 diesel engines. This information should be considered any time the head gasket is replaced.
Four different head gasket thickness options are currently available and provide a variety of gasket thickness options to choose from. Selecting a replacement head gasket requires measuring the amount of piston protrusion above the deck of the block. After determining the piston height, select the appropriate replacement gasket from the chart below. The gaskets are further identified by a different number of notches on the end of each gasket.
NOTE: The charts in the original service manuals are no longer valid.
Engine Builders: The AERA Technical Committee offers the following information on swirl chamber replacement on Volkswagen 1.9L diesel VIN AAZ 1993-1998 cylinder heads.
When installing a MLS head gasket on an engine that had used a composite gasket, correct protrusion of the precombustion chambers (precups) is critical to obtaining a proper head gasket seal. If the precups are recessed below the head surface they must be removed and replaced. Correct protrusion may also be obtained by machining the counterbores to the correct depth after the head surface has been machined.
To correctly change the swirl chamber, Volkswagen offers the following recommendations.
- Drive out the swirl chamber by working through the fuel injector opening using a suitable mandrel. CAUTION: protect the threads in the fuel injector opening from damage.
- Clean swirl chamber contact surface in cylinder head to remove combustion deposits. Installation position is determined by groove and guide tabs.
- Place new swirl chamber in position and drive in with a soft-faced hammer. Measure the protrusion of the swirl chamber; .0028? is maximum allowed (see Figure 2, above).
NOTE: A .001?-.002? protrusion is ideal, however, precup bore clearance is not as critical.
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