Before disassembling the cylinder head, you may want to fabricate some containers to hold the various parts, as some of them can be quite small (such as keepers) and easily lost. Also keeping yourself and the components organized will aid in assembly and reduce confusion. Where possible, try to maintain a components original location; this is especially important if there is not going to be any machine work performed on the components.
| Fig. 1: When removing an OHV valve spring,
use a compressor tool to relieve the tension from the retainer
|
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. 2: A small magnet will help in removal
of the valve locks
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| Fig. 3: Be careful not to lose the small
valve locks (keepers)
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| Fig. 4: Remove the valve seal from the valve
stem — O-ring type seal shown
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| Fig. 5: Removing an umbrella/positive type
seal
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| Fig. 6: Invert the cylinder head and withdraw
the valve from the valve guide bore
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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.
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. 7: Exploded view of a valve, seal, spring,
retainer and locks from an OHC cylinder head
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| Fig. 8: Example of a multi-valve cylinder head.
Note how it has 2 intake and 2 exhaust valve ports
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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. 9: C-clamp type spring compressor and an
OHC spring removal tool (center) for cup type followers
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| Fig. 10: Most cup type follower cylinder
heads retain the camshaft using bolt-on bearing caps
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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. 11: Position the OHC spring tool in
the follower bore, then compress the spring with a C-clamp
type tool
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NOTE: Special valve seal removal tools are available. Regular or needlenose 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. 12: Example of the shaft mounted rocker
arms on some OHC heads
|
| Fig. 13: Another example of the rocker arm type
OHC head. This model uses a follower under the camshaft
|
| Fig. 14: Before the camshaft can be removed,
all of the followers must first be removed . . .
|
| Fig. 15: . . . then the camshaft can be removed
by sliding it out (shown), or unbolting a bearing cap (not
shown)
|
| Fig. 16: 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. 17: . . . then remove the valve locks
from the valve stem and spring retainer
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| Fig. 18: Remove the valve spring and retainer
from the cylinder head
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| Fig. 19: Remove the valve seal from the guide.
Some gentle prying or pliers may help to remove stubborn ones
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NOTE: Cylinder heads that have seen a lot of miles and/or abuse may have mushroomed the valve lock groove 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. 20: All aluminum and some cast iron
heads will have these valve spring shims. Remove all of them
as well
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