Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Valves

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REMOVAL & INSTALLATION



  1. Number the valves in the head with a permanent marker for reinstallation identification.
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  3. Loosen each cam bearing nut about 1 turn at a time to prevent bending the camshaft. Remove the bearing caps and lift off the camshaft. Remove the lifters. Keep hydraulic lifters upside down to prevent leak-down. Lifters MUST be reinstalled in their original location.
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  5. Block the head on wooden supports in a position that permits use of the type of valve spring removing tool you are going to use. Volkswagen uses tool VW 541, although you should be able to perform the job with several other available removers (the locking C-clamp type is popular).
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  7. Compress the valve springs and remove the stem locks and retainers. Remove the valve springs. Keep the parts and each valve separate and in order for reinstallation. It is important that the valves are installed back in their same location. Remove the lower valve spring seats and valve stem oil seals. Remove the valves, keep them in order in case the identification marking wears off.
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  9. Clean valve faces, tips and combustion chambers with a rotary wire brush or bench grinder wire wheel. Do not wire brush the valve stems, take care not to damage the valve seats. Remove the carbon, do not just burnish. If a stubborn carbon deposit is encountered, use a blunt drift to break the carbon loose. Again use caution around the valve seat.
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  11. Inspect the valves and guides as described later. Measure valve guide clearance.
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  13. If a water leak is suspected, or the valve seats, guides or valves need machine work, take the head and parts to the machine shop. Now is also a good time to have the head super cleaned in a cold parts cleaner, the machine shop can handle the job. However, never allow the aluminum head to be hot tanked, this will damage the head and make replacement necessary.
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  15. After all machine work has been done and all the new parts are on hand, install the valves with new oil seals.
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  17. Install the camshaft (refer to the procedure in this section).
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INSPECTION



See Figures 1, 2 and 3

Check the sealing face of the valves and seats. They may be uneven and worn but there must be a distinct ring around the valve showing where it sealed against the seat. If there is any gap or signs of burning, the valve must be replaced and the seat reground.

To check the valve guides, place a new valve in the guide with the end of the stem flush with the camshaft end of the guide. Set a dial indicator against the valve head and rock the valve side-to-side. If the free-play is more than 0.039 inches (1.0mm) on gasoline engines or 0.051 inches (1.3mm) on diesel engines, the guides should be replaced. The guides are pressed out from the camshaft side of the head.



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Fig. Fig. 1: Position a dial indicator, then measure the valve guide clearance with the end of the valve stem flush with the camshaft end of the guide



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Fig. Fig. 2: Valve stems may be rolled on a flat surface to check for bends



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Fig. Fig. 3: Use a micrometer to check the valve stem diameter

REFACING VALVES



On all engines, machining the intake valves is not recommended, they should only be hand-lapped. See the valve chart in this section for information on face angles and dimensions. To hand lap the valves:

  1. Invert the cylinder head, lightly lubricate the valve stem and install the valves in the head as numbered.
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  3. Moisten the suction cup on the lapping tool and attach to the valve head.
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  5. Slightly raise the valve from the seat and apply a small amount of valve grinding compound to the seat.
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  7. Rotate the lapping tool and valve between the palms of your hands while gently pushing the valve into the seat. Lift the tool often and turn the valve to a new position to prevent grooving.
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  9. Continue until a smooth polished surface is evident on the valve and valve seat. Remove the valve from the head and clean away all traces of lapping compound, especially from the guide.
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CAUTION
The exhaust valves in the 16-valve engine are sodium-filled and must not be machined. Improper handling or disposal can cause serious personal injury. To dispose of sodium-filled valves:

  1. Wear protective gloves and goggles. Sodium reacts violently with water; make sure the work area is dry.
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  3. Clamp the valve in a vise and saw the head off with a hack saw. Do not use power tools.
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  5. Throw the valve pieces into a bucket of water and stand back. When the reaction is complete, the valves can be safely thrown away.
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