Timing Chain: Inspection

WARNING: This page is about a different car, the 2004 Toyota MR2, 2003 Toyota MR2, and 2002 Toyota MR2. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT TIMING CHAIN AND TIMING SPROCKETS
1. Using vernier calipers, measure the length of the 16 links with the chain fully stretched.
  
  Fig 1: Measuring Timing Chain For Excessive Length
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Maximum chain elongation: 122.6 mm (4.827 in.)
  
  If the elongation is greater than maximum, replace the chain.
  
  NOTE: Make the same pulling measurements at 3 or more places selected at random.
2. Wrap the chain around the timing sprocket.
3. Using vernier calipers, measure the timing sprocket diameter with the chain.
  
  Fig 2: Measuring Sprocket Diameter
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  NOTE: Vernier calipers contact the chain rollers for measuring.
  
  Minimum sprocket diameter (w/ Chain):
  1. Camshaft: 97.3 mm (3.831 in.)
  2. Crankshaft: 51.6 mm (2.031 in.)
  If the diameter is less than minimum, replace the chain and sprockets.
INSPECT DRIVE BELT IDLER
Check that the pulley rotates smoothly.

If necessary, replace the bearing. See step 2 under REPLACEMENT.
INSPECT CHAIN TENSIONER SLIPPER AND VIBRATION DAMPER
Measure the chain tensioner slipper and vibration damper wear.

Fig 3: Inspecting Chain Tensioner Slipper & Vibration Damper For Wear
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Maximum wear: 1.0 mm (0.039 in.)

If the wear is greater than maximum, replace the slipper and/or damper.
INSPECT CHAIN TENSIONER
1. Check that the plunger moves smoothly when the ratchet pawl is raised with your finger.
2. Release the ratchet pawl and check that the plunger is locked in place by the ratchet pawl and does not move when pushed with your finger.
INSPECT OIL JET . See INSPECTION .
INSPECT DRIVE BELT TENSIONER
Check the oil leakage and crack.

If necessary, replace the drive belt tensioner.