On engines with a cat (catalyst) it is important not to allow debris or fluids to fall down into the exposed exhaust pipes.

Spark plugs were loosened but not removed at this stage. The inlet manifold with the fuel injectors is still attached to the head.

The engine and gearbox assembly was supported by a block of wood jammed between the gearbox sump and the alloy cross member.

The power steering pump was now visible behind a part of the offside engine mounting. This was covered in oil and grime - but the oil was from the leaking head gasket, not from the PAS pump itself.

The hard rubber 'top rubbing block' for the timing chain can just be seen.

Oil was vacuumed out from pockets in the head using a DIY tool - a  thin plastic tube, an old paint tin as a reservoir and a vacuum cleaner.

It was important not to let debris or any small tool fall down into the timing chain - if it could not be retrieved the entire engine and gearbox would have to be removed to strip off the front of the engine.

Clean (and empty!) supermarket bags were stuffed down amidst the chain to block off the passageway.

Never buy cheap tools!

Old newspapers were used to catch stray oil - and with one particularly appropriate headline in view!

This was an article about repair of domestic appliances - instead of throwing them away.

It takes about half a day properly to clean up a cylinder head, after which the valves can be removed and any necessary grinding undertaken.

At this stage, extreme cleanliness is not necessary - that comes later.

A xylene based felt tip pen (impervious to paraffin) proved a great asset. After degreasing, the same pen was used to mark the tops of the hydraulic tappets before they were removed (using a magnet).

The two camchain sprocket wheels are shown. Sprockets and a reliable chain are the alternative to a cambelt - used on most modern cars because of cheapness and ease of assembly in factories.

It is easy to grind a valve into the wrong seat - so everything was numbered to minimise the chances of a mistake.

It was now ready to be finally washed with paraffin and pressure hosed.

These surfaces are not critical and can if necessary be 'bodged up' using exhaust sealant.

Like the rest of the head, these surfaces were in remarkably good condition after 204,000 miles and 18 years.

When years later I sold the car it had done more than  232,000 miles.

There are small areas of minor corrosion on the face of the head but nothing too serious.

Years of experience is the best guide as to what you can get away with.

The main oil pressure feed to the cylinder head can be seen. All the oil ways in the head were flushed through with paraffin - which was then vacuumed out.

This was  a little risky because the vacuum cleaner could have developed a mildly explosive mixture of paraffin vapour and air - and be ignited by the sparks from its commutator motor.

When storing valves in this way - only ever remove one at a time, even if they are numbered! If they are mixed up they have to be reground, and it is important to grind in the valves in this engine as little as possible.

Only 15 more to do!

A close-up view of the tappet bores is shown in the next photo.

Any damage to these surfaces can render the whole cylinder head scrap. A special tool is used to slide down these bores to protect the surfaces from scoring when a valve spring compressor is used.

The proper tool is a Saab part (not sold to retail customers) so as a substitute, a section of thin wall Waitrose drinks bottle was used. It worked perfectly.

The tappet bore is protected by a thin but tough plastic sleeve - made from an old drinks bottle - see next photo. It cannot be seen in-situ in this poor quality photo.

Damage to the bores could render the hydraulic locking action of the tappets inoperative - so the valve clearances would not be correct and the engine would be very noisy.

Sold by the innocent drinks company in 'hard' PETE plastic (that keeps its shape well) they can easily be cut to length with a sharp knife.

It is best to remove all traces of the paper labels.

The company says it is interested in alternative uses for its bottles - this must be one of the most unusual.

Gravity is a useful aid, and the head has to be suspended 300mm or more above the ground, allowing room for the spring compressor. An old kitchen cabinet proved an excellent workbench.

The faces of the inlet manifold are yet to be cleaned.

The brass plug shown centrally in the manifold is the temperature sensor for the engine ECU.

Remarkably, this one was in excellent condition - and with no sludge in the waterways having collected at this low point, signifying that the coolant had been kept to strength and that there had been no serious leakage of exhaust gases into the coolant.

These were encouraging signs.

At the slightest movement the oily chain would slide all the way out of the engine - so you had to start over again ledging it into place.

The top chain guide is pivoted, while the lower one is fixed. On these later engines a more sensible design of chain tensioner is used - earlier models were more difficult to dismantle.

Here the guides are held together (neatly out of the way) and the chain is bundled up and held in place by sticky tape. The tape had of course to be removed as soon as the head was in place - and before the adhesive gripped too strongly on the clean metal surfaces.

This proved an easy method of holding the components in place - according to 'the book' you need an assistant.

A stud made from an old cylinder head bolt with its head cut off has been inserted to the lower right - the head was then located on this and simply swung into place clockwise over the timing chain assembly.

It was given a final surface clean using a powerful degreasing agent, after which the surfaces were not touched, even with clean hands.

To achieve a 90 degree final torque loading, the tops of the bolts were dabbed with white paint after the 60 ft-lb tightening, and each was then rotated in turn a further 90 degrees - give or take maybe 5 degrees.