Suggested by Cosmo
While chatting with Cosmo, he mentioned a novel method of checking for play in a cylinder's wrist pin. Here is the procedure:
This test is easy to do on a 1.6 16-valve engine as the spark plug hole is in the center of the cylinder head. 1.3 and 1.6 8-valve engines may require you to push the piston top in a levering fashion. To protect the sparkplug threads from damage, you might want to put a layer of tape around the screwdriver blade shaft where it touches the spark plug hole.
Remove the sparkplugs to make turning over the engine an easier task.
Place a 17mm socket and a long-handled rachet (slip a hydraulic jack handle over the rachet handle for more leverage) on the crank bolt. Insert the socket between the two widely-spaced fan blades.
Starting with Cylinder #1, Carefully place a long-bladed screwdriver into the sparkplug hole until it rests on the top of the piston. SLOWLY and CAREFULLY rotate the crank with the socket and ratchet in the clockwise direction until the piston goes past Top Dead Center (TDC) and the screwdriver starts to drop. The piston will be "dragged" down the cylinder causing the wrist pin's "slop space" (if any) to be on the top the wrist pin. If you are doing this procedure on an 8-valve engine, you might want to "eyeball" the piston position with a flashlight instead of using the screwdriver as an indicator.
Use the screwdriver to gently push down on the top of the piston.
If the piston moves downward (and the cylinder has good compression), you have a worn wrist pin that is most likely making mechanical noise.
Repeat the above steps for the rest of the cylinders.