REMOVE & INSTALLATION
See Figures 1 and 2
- Disconnect the negative battery cable.
- Remove the cylinder head(s) from the vehicle, as outlined earlier in this section, as place on a clean surface.
- Remove the rocker arms or camshafts, as applicable. Using a suitable valve spring compressor, compress the valve spring and remove the valve keys using a magnetic retrieval tool.
- Slowly release the compressor and remove the valve spring caps (or rotors) and the valve springs.
- Fabricate a valve arrangement board (piece of cardboard with holes punched through) to use when you remove the valves, which will indicate the port in which each valve was originally installed (and which cylinder head on V6 models). Also note that the valve keys, rotators, caps, etc. should be arranged in a manner which will allow you to install them on the valve on which they were originally removed.
- Remove the discard the valve seals. On models using the umbrella type seals, note the location of the large and small seals for assembly purposes.
- Thoroughly clean the valves on the wire wheel of a bench grinder, then clean the cylinder head mating surface with a soft wire wheel, a soft wire brush, or a wooden scraper. Avoid using a metallic scraper, since this can cause damage to the cylinder head mating surface, especially on models with aluminum heads.
- Using a valve guide cleaner chucked into a drill, clean all of the valve guides.
Be sure that all traces of lapping compound have been cleaned OFF before the valves are installed.
- Lubricate all of the valve stems with a light coating of engine oil, then install the valves into the proper ports/guides.
- If the umbrella-type valve seals are used, install them at this time. Be sure to use a seal protector to prevent damage to the seals as they are pushed over the valve keeper grooves. If O-ring seals are used, don't install them yet.
- Install the valve springs and the spring retainers (or rotators), and using the valve compressing tool, compress the springs.
- If umbrella-type seals are used, just install the valve keepers (white grease may be used to hold them in place) and release the pressure on the compressing tool. If O-ring type seals are used, carefully work the seals into the second groove of the valve (closest to the head), install the valve keepers and release the pressure on the tool.
If the O-ring seals are installed BEFORE the springs and retainers are compressed, the seal will be destroyed.
- After all of the valves are installed and retained, tap each valve spring retainer with a rubber mallet to seat the keepers in the retainer.
Valve refacing should only be handled by a reputable machine shop, as the experience and equipment needed to do the job are beyond that of the average owner/mechanic. During the course of a normal valve job, refacing is necessary when simply lapping the valves into their seats will not correct the seat and face wear. When the valves are reground (resurfaced), the valve seats must also be recut, again requiring special equipment and experience.
See Figures 3 and 4
After machine work has been performed on the valves, it may be necessary to lap the valve to assure proper contact. For this, you should first contact your machine shop to determine if lapping is necessary. Some machine shops will perform this for you as part of the service, but the precision machining which is available today often makes lapping unnecessary. Additionally, the hardened valves/seats used in modern automobiles may make lapping difficult or impossible. If your machine shop recommends that you lap the valves, proceed as follows:
- Set the cylinder head on the workbench, combustion chamber side up. Rest the head on wooden blocks on either end, so there are two or three inches between the tops of the valve guides and the bench.
- Lightly lube the valve stem with clean engine oil. Coat the valve seat completely with valve grinding compound. Use just enough compound that the full width and circumference of the seat are covered.
- Install the valve in its proper location in the head. Attach the suction cup end of the valve lapping tool to the valve head. It usually helps to put a small amount of saliva into the suction cup to aid it sticking to the valve.
- Rotate the tool between the palms, changing position and lifting the tool often to prevent grooving. Lap the valve in until a smooth, evenly polished seat and valve face are evident.
- Remove the valve from the head. Wipe away all traces of grinding compound from the valve face and seat. Wipe out the port with a solvent soaked rag, and swab out the valve guide with a piece of solvent soaked rag to make sure there are no traces of compound grit inside the guide. This cleaning is important.
- Proceed through the remaining valves, one at a time. Make sure the valve faces, seats, cylinder ports and valve guides are clean before reassembling the valve train.