Fiat Uno Manual

Examination and renovation (1116 cc and 1301 cc engines)
Engine / Examination and renovation (1116 cc and 1301 cc engines)

1 The procedures are similar to those described in Section 18 covering the following:
Cylinder block and crankcase Crankshaft and bearings
Pistons and piston rings Flywheel
2 The following additional items must also be examined.

Oil pump
3 Carefully, clamp the pump housing in a vice, shaft downwards.

4 Take off the pump cover, with the suction pipe. This will release the oil pressure relief valve inside. Also inside is a filter.

5 Remove the internal cover plate.

6 Take out the driveshaft and the gears.

7 Clean and examine all the parts. Measure the clearances against the Specifications. The end clearance is measured by putting a straight-edge across the cover face.

8 The oil pump should only need replacements after very long mileage, when the rest of the engine is showing great signs of wear.

9 The length of a new gear can be measured against the old gear to see if a new gear will restore the end clearance to the Specifications.

Otherwise the housing must be changed.

10 The driven gear shaft is mounted in the housing with an interference fit. If there is any slackness, a new housing (which will come with shaft fitted) must be used.

11 The oil pump shares its drive with the distributor.

Camshaft, cam followers and shims
12 The camshaft journals and cams should be smooth, without grooves or scores.

13 Wear in the camshaft carrier bearings can only be rectified by renewal of the carrier.

14 Cam follower wear is usually very small and when they show slackness in their bores, it is probably the light alloy of the camshaft carrier which has worn.

15 Always measure the thickness of the valve clearance shims using a metric micrometer.

Any grooving or wear marks in the shims should be rectified by renewal with ones of similar thickness.

Auxiliary shaft
16 The shaft journals, the fuel pump eccentric, and the drivegear for the distributor and oil pump should be smooth and shiny. If not, the shaft will have to be renewed.

17 The bushes should still be tight in the cylinder block, their oil holes lined up with those in the block.

18 Measure the bearing clearance. If excessive, the bushes will have to be renewed. They are a press fit, and require reaming with a special reamer after fitting.

This is a job best done by a Fiat agent with the special tools.

19 Ensure the new bushes are fitted with the oil holes lined up.

20 Also check the driven gear and its bush.

21 It is recommended a new oil seal is fitted in the endplate. Hold the shaft in a vice, and remove the pulley. Fit the new oil seal in the endplate, lips inwards.

Timing belt tensioner
22 Check the bearing revolves smoothly and freely, and has no play. Do not immerse it in cleaning fluid, as it is partially sealed. Wipe the outside, and then smear in some new general purpose grease.

23 The action of the spring will have been felt when the belt was taken off. It should be cleaned, and oiled, to prevent seizure through dirt and rust.

24 Note the circlip on the engine right-hand mounting bracket. This retains the timing belt tensioner plunger.

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