Toyota Celica/Supra 1971-1985 Repair Guide

Timing Chain and Tensioner

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REMOVAL & INSTALLATION



8R-C and 18R-C Engines

See Figure 1



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Fig. Fig. 1: Timing chain stretch measurement-8R-C and 18R-C engines

  1. Remove the cylinder head and timing chain cover as previously detailed.
  2.  
  3. Remove the timing chain (front) together with the camshaft drive sprocket.
  4.  
  5. Remove the crankshaft sprocket and oil pump jack shaft, complete with the pump jack shaft, complete with the pump drive chain (rear). Remove the chain vibration damper.
  6.  

Both timing chains are identical; tag them for proper identification during installation.

  1. Inspect the chains and sprockets for wear or damage. Clean the chains with solvent.
  2.  
  3. Use a vernier caliper to measure the amount of stretch of both chains. Measure any 17 links while pulling the chain which is being measured taut.
  4.  
  5. Repeat Step 5 at two other places on each chain. Replace either of the chains if any of the 17 link measurements exceed 5.792 inch (147.11mm) or if the difference between the minimum and maximum readings is more than 0.0078 inch (0.198mm), on any one chain.
  6.  
  7. Remove the plunger and spring from one of the chain tensioners. Inspect all of the parts of the tensioner for wear of damage. Fill it with oil and assemble it if it is not defective.
  8.  
  9. Repeat Step 7 for the other tensioner.
  10.  

Do not mix the parts of the two chain tensioners together.

To install:
  1. Position the No. 1 piston at TDC by having the crankshaft keyway point straight up, toward the cylinder head.
  2.  
  3. Align the oil pump jack shaft, with its keyway pointing straight up as well.
  4.  
  5. Align the marks on the timing sprocket and the oil pump drive sprocket with each of the marks on the chain.
  6.  
  7. Install the chain and sprocket assembly over the keyways, while retaining alignment of the chain/sprocket timing marks.
  8.  


WARNING
Use care not to disengage the welch plug at the rear of the oil pump driveshaft by forcing the sprocket over its keyway.

  1. Install the oil pump drive chain vibration damper.
  2.  
  3. Install the gasket for the timing chain cover.
  4.  

Use liquid sealer on the gasket before installation.

  1. Install both of the chain tensioners in their respective places, being careful not to mix them up. Tighten their securing bolts to 12-17 ft. lbs. (16-23 Nm).
  2.  


WARNING
Use care when installing the chain tensioner bolts; they have oil holes tapped in them.

  1. Fit the camshaft drive sprocket over the keyway on the oil pump driveshaft. Tighten its securing nut to 58-72 ft. lbs. (78-97 Nm).
  2.  
  3. Install the camshaft drive chain over the camshaft drive sprocket. Align the mating marks on the chain and sprocket.
  4.  
  5. Apply tension to the chain by tying it to the chain tensioner. This will prevent it from falling back into the timing chain cover once it is installed.
  6.  
  7. Install the timing chain cover and cylinder head as previously outlined.
  8.  

20R, 22R and 22R-EC Engines

See Figures 2 through 14



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Fig. Fig. 2: Remove the crankshaft pulley using a suitable puller



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Fig. Fig. 3: Remove the three water bypass tube bolts



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Fig. Fig. 4: Unbolt the heater tube



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Fig. Fig. 5: Remove the bolt holding the alternator adjuster bracket to the chain cover



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Fig. Fig. 6: Remove the six timing chain cover bolts shown by the thin arrows



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Fig. Fig. 7: Lift the chain off the damper, then slide the chain and sprocket off together



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Fig. Fig. 8: Try to remove the pump drive spline and crankshaft sprocket by hand



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Fig. Fig. 9: Measure the length of the chain fully stretched; do this in three places along the linkage



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Fig. Fig. 10: Using a vernier caliper, measure the tensioner



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Fig. Fig. 11: Tighten down the damper bolts



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Fig. Fig. 12: Place the chain on the sprocket with the single bright link aligned with the timing mark on the sprocket



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Fig. Fig. 13: Place the chain on the camshaft sprocket



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Fig. Fig. 14: Install the oil pump spline over the crankshaft key

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the cylinder head.
  4.  
  5. If necessary, remove the radiator.
  6.  
  7. If necessary, remove the oil pan.
  8.  
  9. Remove the drive belts and crankshaft pulley.
  10.  
  11. Remove the three bolts retaining the water by pass pipe.
  12.  
  13. Remove the heater tube. Unbolt the alternator adjusting bracket to the chain cover. Move the bracket towards the alternator.
  14.  
  15. Remove the chain cover bolts, then separate the cover from the engine.
  16.  
  17. Separate the chain from the damper and remove the chain, complete with the camshaft sprocket.
  18.  
  19. Remove the crankshaft sprocket and the oil pump drive with a puller.
  20.  
  21. Inspect the chain for wear or damage. Replace it if necessary.
  22.  
  23. Inspect the chain tensioner for wear. If it measures less than 0.43 inch (11mm), replace it.
  24.  
  25. Check the dampers for wear. If their measurements are below the following specifications, replace them.

    Upper damper: 0.20 inch (5.08mm)
     
    Lower damper-0.18 inch (4.57mm)
     

  26.  

To install:
  1. Rotate the crankshaft until its key is at TDC. Slide the sprocket in place over the key.
  2.  
  3. Place the chain over the sprocket so its single bright link aligns with the mark on the camshaft sprocket.
  4.  
  5. Install the cam sprocket so the timing mark falls between the two bright links on the chain.
  6.  
  7. Fit the oil pump drive spline over the crankshaft key.
  8.  
  9. Install the timing cover gasket on the front of the block.
  10.  
  11. Rotate the camshaft sprocket counterclockwise to remove the slack from the chain.
  12.  
  13. Install the timing chain cover and cylinder head.
  14.  
  15. Install the remaining components.
  16.  
  17. Connect the negative battery cable.
  18.  

4M-E and 5M-E Engines
  1. Remove the cylinder head and timing chain cover as previously outlined.
  2.  
  3. Remove the chain tensioner assembly (arm and gear).
  4.  
  5. Unfasten the bolts retaining the chain damper and damper guide, then withdraw the damper and guide.
  6.  
  7. Remove the oil slinger from the crankshaft.
  8.  
  9. Withdraw the timing chain.
  10.  
  11. Inspect the chain for wear or damage. Replace it if necessary.
  12.  

Installation is performed in the following manner:
  1. Position the No. 1 cylinder at TDC.
  2.  
  3. Position the crankshaft sprocket with the mark downward, facing the oil pan.
  4.  
  5. Align the Toyota trademarks on the sprockets.
  6.  
  7. Fit the tensioner gear assembly on the block.
  8.  

The gear's dowel pin should be positioned 1.5 inches (38.1mm) from the surface of the block.

  1. Install the chain over the two gears while maintaining tension.
  2.  
  3. Install both of the vibration dampers and the damper guide.
  4.  
  5. Fit the oil slinger to the crankshaft.
  6.  
  7. Tie the chain to the upper vibration damper, to keep it from falling into the chain cover, once the cover is installed.
  8.  
  9. Install the timing chain cover as previously detailed.
  10.  
  11. Perform the cylinder head installation procedure as previously detailed.
  12.  

If proper valve timing cannot be obtained, it is possible to adjust it by placing the camshaft slotted pin in the second or third hole on the camshaft timing gear, as required. If the timing is out by more than 15°deg;, replace the chain and both of the sprockets.

 
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