Fiat X1/9 1500cc Engine
Timing Belt Replacement, Cam Timing and Static Ignition Timing.
Photos courtesy of Don Doan.
Introduction
This document outlines how to replace a timing belt on a Fiat X1/9 1500cc engine. It shows how to align the crankshaft pulley, flywheel and cam pulley for correct cam timing. Finally, it shows the approximate distributor position for static ignition timing.
The photos in this guide are of a 1500cc engine with fuel injection, electronic ignition and air conditioning. Differences to a 1300cc engine are mentioned where appropriate however please double check any differences are correct as my personal experience is only with a 1500cc engine.
Some other important points to note:
•The static ignition timing of a carbureted engine is 5º BTDC.
•The static ignition timing of a fuel-injected engine is 10º BTDC.
•Ignition timing is set relative to the position of number 4 cylinder – not number 1 cylinder as on most other manufacturer’s engines.
•The Fiat X1/9 1500cc engine is a non-interference engine whereas the 1300cc engine is not. This means that even if the cam timing is off, the pistons and valves will not collide (or “interfere” with one another) in a 1500cc engine. Thus, replacement of the timing belt at the recommended intervals is especially important for a 1300cc engine.
•For a 1500cc engine, with the crankshaft pulley at TDC, the cam pulley should align with the pointer on the belt guard.
•For a 1300cc engine, with the crankshaft pulley at TDC, the cam pulley should align with the pointer on the side engine mount.
•The most accurate TDC mark for the crankshaft pulley is a line cast into the front crank seal housing. The reference pointer may be bent or may have been removed at some stage and installed slightly off.
•The flywheel is the next best indicator of crankshaft TDC but it too was removed at some stage, it may have been refitted 180º out.
•The photos in this guide are of a clean engine with some parts and timing marks painted to make them easier to see. This is not the case with a normal engine.
Engine Components & Terminology
The following photo is used to identify important engine components that will be referred in this guide. Although the terms used may not be technically correct, hopefully this photo will help avoid confusion.
Rear of Engine |
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Front of Engine |
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Toothed timing belt
Side engine mount
Crank pulley timing fingers (0º, 5º & 10º marks)
Cam pulley TDC mark (pointer on belt guard)
Camshaft or “Cam” pulley
Distributor
Timing belt tensioner pulley
Crankshaft or “Crank” pulley.
Auxiliary shaft pulley
Timing Belt Replacement Procedure
The following photos show how to replace the timing belt.
Before changing the timing belt, it is good practice to set the engine to TDC. Do this by rotating the crankshaft pulley clockwise until the mark on the crank pulley is aligned with the right hand pointer on the timing finger (refer photo 2).
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Photo 1 |
Photo 2 |
This is what the 1500 cc engine looks like removed from the car. First, the yellow |
1500cc engine crank pulley TDC alignment. |
plastic belt cover has to be removed by undoing four 10mm bolts – two at the |
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top, one in the centre and one at the bottom. |
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Photo 3 |
Photo 4 |
With the belt cover removed, the cam pulley, belt tensioner pulley, and auxiliary |
Using a 17mm socket, loosen the tensioner pulley nut. The tensioner pulley is |
shaft pulley are all visible. |
situated on bracket secured by a large gold pin to the lower left of the pulley. |
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This allows the pulley to be rotated to the left while remaining on its attaching |
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stud. You will not have to remove this pulley to remove or change the belt - just |
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move it to the side. |
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