Reconditioning

CYLINDER HEAD RECONDITIONING:

General:
This section provides the specifications and special reconditioning information necessary to repair the Volkswagen cylinder head. Special service tools and machine shop services are required for most cylinder head reconditioning.

The information given under this reconditioning heading assumes the cylinder head is removed. For cylinder head removal procedures, see Cylinder Head Removal and Installation.

Refer to Diagrams, Exploded Views for cylinder head assembly details. Diagrams

Cylinder Head and Camshaft:
Cylinder heads with small, fine cracks between valve seats and plug threads are usable provided the cracks are not more than 0.5 mm (0.02 in.) wide, and do not extend into more than the first few spark plug threads.

Checking Cylinder Head Distortion:

Measure cylinder head for distortion. Maximum permissible distortion: 0.1 mm (0.004 in.).

Minimum resurfacing dimension is measured from the valve cover gasket surface to the cylinder head gasket surface. Minimum: 132.8 mm (5.220 in.).

Camshaft, Checking Axial Play:

Check camshaft axial play. Measure with valve lifters removed, and first and last bearing caps installed. Wear limit: 0.15 mm (0.0059 in.).

If the camshaft was removed or if installing a new cylinder head, lubricate the contact surfaces between the cam lobes and the hydraulic cam followers prior to start-up. When removing and installing the camshaft, be sure to follow the procedure given under To remove and install camshaft. Incorrect camshaft removal or installation can result in a damaged camshaft or cylinder head.

Camshaft and Cam Followers:

Camshaft Bearing Caps:

Camshaft bearing caps or cam followers should not be interchanged. Note the bearing cap offset during assembly. Camshaft bearing caps are machined offset and fit only one way.

CAUTION: After installing new cam followers, the engine should not be started for at least 30 minutes. New cam followers are at full height and must be allowed to bleed down to their proper height. Failure to do this may cause valve or piston damage.

Valves:
All gasoline engine valves are sodium-filled and should be hand-lapped only.

WARNING: Sodium filled valves, when discarded, must be disposed of properly to avoid personal injury Always wear protective goggles or glasses. By hand, cut off the valve stem near the head of each valve. Use only a hack saw. Do not use a power saw. Sodium reacts violently with water. Do not let water contact the valve while cutting. Throw the valve parts (no more than 10 valves at a time) into a bucket of water and stand clear. Discard the valves when the reaction has stopped.

Valve Guides:

Checking Valve Guide Wear:

Special tools and a press are required to replace valve guides. Check valve guide wear with a new valve. Inspect the valve seats to ensure that the cylinder head can be reconditioned before installing new valve guides.

Original valve guides (without shoulders) are pressed out from the camshaft side of the cylinder head. Replacement valve guides (with shoulders) are pressed out from the combustion chamber side of the cylinder head. Lubricate new valve guides with oil and press them in from the camshaft side until the shoulder is fully seated.

NOTE: Where available, replace valve guides using Volkswagen special tools. Use of other press tools may damage the cylinder head. Use VW tool no. 3121 (order no. T03 121 000 1 5 ZEL) for installation and removal. Ream the valves guides using VW special tool no. 3120.

Valve Seats:

Checking Installed Valve Height:

When resurfacing valve seats, there is a limit to the amount of material that can be removed. If too much material is removed, the final assembly will leave too little space for the hydraulic cam follower to function correctly. The maximum refacing dimension-the maximum amount of material that can be removed from the valve seat-is calculated from the measurement shown in the image above.

Measure dimension "a" in the image above (distance between top of valve stem and gasket surface of cylinder head), and subtract the minimum dimension, as given in specification below. The difference is the maximum amount of material that can be removed from the valve seat.

Minimum Dimensions for Calculating Valve Seat Refacing Dimensions:
Intake: 33.8 mm (1.331 in.).
Exhaust: 34.1 mm (1.343 in.).