If you're having the head and valves done, then you'll need to re-set the valve gaps [shims]. An easy way to do this off the car is to make a jig that you can use on the shed bench or B&D workstation:
1. Cut two strips of flat aluminium [e.g 3 mm thick] each about 500mm long - a good hardware store will sell strips of ally in various lengths that can be cut to suit.
2. At the same shop, buy a packet of large steel washers with diameter holes big enough to accept the cylinder head bolts.
3. Take a cylinder head bolt to a fastener supplier and get a set of nuts - one for each bolt.
4. Mark and drill holes in each strip to match the cylinder head bolt holes. [Use the valve bucket tower and a Phillips screwdriver to mark their respective positions.]
4. Fit the tower to the cylinder head and run the cylinder head bolts through. Mark where the ally blocks the valves. Cut circular notches in each ally strip to allow the valves freedom to open and close.
5. Assemble the cylinder head with its valves.
To put the jig to work:
1. Assemble the valves and springs into the head, put on the bucket tower, insert first datum shims, buckets, camshaft and cam brackets - all loose at this stage.
2. Run the cylinder head bolts through the assembly.
3. Gently tilt the assembly and put the one ally strip onto the line of bolts on the cylinder head base side. Pop a washer on each bolt and then finger tight a nut on each. [The ally strips protect the base of the cylinder head and the washers protect the ally strips.]
4. Repeat [3] for the opposite side.
5. Gently tighten the cylinder head bolts in a suitable order to pull everything together as though it were mounted on the engine. [Check to ensure the valves are free to move and are not blocked by the ally strips!]
6. Screw two rubbish bolts halfway into the holes in the camshaft flange - ones you don't mind munting the threads a bit. [Use a stout screwdriver between them as a lever to rotate the camshaft to get your valve gap measurements.]
7. Dissassemble and reassemble the jig as you need to thereafter whilst you flap around with different shim combos.
Voila!
Hint:
Measuring valve gaps with straight feeler gauges can be awkward and potentially give misleading results. If you don't have a set of angled feeler gauges [and they can be difficult to find] buy a straight set, grind off the swivel pin and dissassemble the thing. Gently bend each gauge so that it fits easily under the cam lobe in the confined space provided in the P6 bucket tower. Keep the collection of gauges in a plastic bag or tub for use next time.
