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.