Whether it is a single or dual overhead camshaft cylinder head, the disassembly procedure is relatively unchanged. One aspect to pay attention to is careful labeling of the parts on the dual camshaft cylinder head. There will be an intake camshaft and followers as well as an exhaust camshaft and followers and they must be labeled as such. In some cases, the components are identical and could easily be installed incorrectly. DO NOT MIX THEM UP! Determining which is which is very simple; the intake camshaft and components are on the same side of the head as was the intake manifold. Conversely, the exhaust camshaft and components are on the same side of the head as was the exhaust manifold.
| Fig. 1: Exploded view of a valve, seal, spring, retainer
and locks from an OHC cylinder head
|
| Fig. 2: Example of a multi-valve cylinder head. Note
how it has 2 intake and 2 exhaust valve ports
|
Most cylinder heads with cup type camshaft followers will have the valve spring, retainer and locks recessed within the follower's bore. You will need a C-clamp style valve spring compressor tool, an OHC spring removal tool (or equivalent) and a small magnet to disassemble the head.
| Fig. 3: C-clamp type spring compressor and an OHC spring
removal tool (center) for cup type followers
|
| Fig. 4: Most cup type follower cylinder heads retain
the camshaft using bolt-on bearing caps
|
NOTE: It is preferred to position the cylinder head gasket surface facing you with the valve springs facing the opposite direction and the head laying horizontal.
| Fig. 5: Position the OHC spring tool in the follower
bore, then compress the spring with a C-clamp type tool
|
NOTE: Special valve seal removal tools are available. Regular or needle nose type pliers, if used with care, will work just as well. If using ordinary pliers, be sure not to damage the follower bore. The follower and its bore are machined to close tolerances and any damage to the bore will effect this relationship.
Most cylinder heads with rocker arm-type camshaft followers are easily disassembled using a standard valve spring compressor. However, certain models may not have enough open space around the spring for the standard tool and may require you to use a C-clamp style compressor tool instead.
| Fig. 6: Example of the shaft mounted rocker arms on some
OHC heads
|
| Fig. 7: Another example of the rocker arm type OHC head.
This model uses a follower under the camshaft
|
| Fig. 8: Before the camshaft can be removed, all of
the followers must first be removed . . .
|
| Fig. 9: . . . then the camshaft can be removed by
sliding it out (shown), or unbolting a bearing cap (not shown)
|
| Fig. 10: Compress the valve spring . . .
|
NOTE: Due to engine varnish, the retainer may stick to the valve locks. A gentle tap with a hammer may help to break it loose.
| Fig. 11: . . . then remove the valve locks from the
valve stem and spring retainer
|
| Fig. 12: Remove the valve spring and retainer from
the cylinder head
|
| Fig. 13: Remove the valve seal from the guide. Some
gentle prying or pliers may help to remove stubborn ones
|
NOTE: Cylinder heads that have seen a lot of miles and/or abuse may have mushroomed the valve lock grove and/or tip, causing difficulty in removal of the valve. If this has happened, use a metal file to carefully remove the high spots around the lock grooves and/or tip. Only file it enough to allow removal.
| Fig. 14: All aluminum and some cast iron heads will
have these valve spring shims. Remove all of them as well
|
