Pistons and connecting rods - examination and renovation
1 Examine the pistons for ovality, scoring, and scratches. Check the connecting rods for wear and damage. The connecting rods carry a letter indicating their weight class; all the rods fitted must be of the same class.
2 The gudgeon pins are an interference fit in the connecting rods, and if new pistons are to be fitted to the existing connecting rods, the work should be carried out by a Ford dealer who will have the necessary tooling. Note that the oil splash hole in the connecting rod must be located on the right-hand side of the piston (the arrow on the piston crown faces forwards).
3 If new rings are to be fitted to the existing pistons, expand the old rings over the top of the pistons. The use of two or three old feeler blades will be helpful in preventing the rings dropping into empty grooves. Note that the oil control ring is in three sections.
4 Before fitting the new rings to the pistons, insert them into the cylinder bore and use a feeler blade to check that the end gaps are within the specified limits (see illustration).
33.4 Checking a piston ring gap at the top of the cylinder bore
5 Clean out the piston ring groove using a piece of old piston ring as a scraper. Be careful not to scratch the aluminium surface of the pistons. Protect your fingers - piston ring edges are sharp.
6 Fit the oil control ring sections with the spreader ends abutted opposite the front of the piston. The side ring gaps should be 25 mm (1.0 in) either side of the spreader gap. Fit the tapered lower compression ring with the “TOP” mark towards the top of the piston and the gap 150º from the spreader gap, then fit the upper compression ring with the gap 150º on the other side of the spreader gap. Note that the compression rings are coated with a molybdenum skin which must not be damaged.
Note also that the compression rings are made of cast iron, and will snap if expanded too far.
See also:
Exhaust manifold - removal and refitting
Note: A new gasket will be required on
refitting.
Removal
1 Disconnect the battery negative lead.
2 On carburettor and CFI engine models
remove the air cleaner as described in the
appropriate Pa ...
Engine/transmission mountings - removal and refitting
Pre-1986 models
1 The engine mountings can be removed if
the weight of the engine/transmission is first
taken by one of the three following methods.
2 Either support the engine under the sump
usi ...
Expansion tank and coolant level sensor - removal and refitting
Removal
1 With the engine cold, slowly unscrew the
expansion tank cap to release any remaining
pressure from the cooling system. Remove
the cap.
2 Place a suitable container beneath the
expansio ...