Jeep CJ 1945-1970 Repair Information

Timing Chain and Tensioner

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REMOVAL & INSTALLATION



L4-134 Engines Before Serial No. 175402 in CJ-2A Models
  1. Remove the timing chain cover.
  2.  
  3. Pull the sprocket forward alternately and evenly until they are free.
  4.  
  5. On installation, align the timing marks on the sprockets. Check the end float between the crankshaft sprocket and the thrust plate. Clearance should be 0.004-0.008 in. (0.1016-0.2032mm). Camshaft gear-to-thrust plate clearance is 0.003-0.055 in. (0.0762-1.397mm). Both clearances are adjustable by shim packs. Check, also, the running clearances between the gears. Proper clearance is 0.000-0.002 in. (0.0000-0.0508mm).
  6.  
  7. Turn the crankshaft so that Nos. 1 and 4 piston are at Top Dead Center (TDC) as indicated by the Top Center (TC) mark on the flywheel seen through the timing hole in the right side of the flywheel housing.
  8.  
  9. Place the camshaft sprocket on the shaft and turn the shaft until the punch mark on the rim of the sprocket faces the punch mark on the crankshaft sprocket.
  10.  
  11. Remove the camshaft sprocket and install the sprocket and timing chain. Timing is correct when a line drawn through the sprocket centers, intersects the timing marks on both sprockets.
  12.  

6-225 Engine

See Figure 1

  1. Remove the timing chain cover.
  2.  
  3. Make sure that the timing marks on the crankshaft and the camshaft sprockets are aligned. This will make installing the parts easier.
  4.  

It is not necessary to remove the timing chain dampers (tensioners) unless they are worn or damaged and require replacement.

  1. Remove the front crankshaft oil slinger.
  2.  
  3. Remove the bolt and the special washer that hold the camshaft distributor drive gear and fuel pump eccentric at the forward end of the camshaft. Remove the eccentric and the gear from the camshaft.
  4.  
  5. Alternately pry forward the camshaft sprocket and then the crankshaft sprocket until the camshaft sprocket is pried from the camshaft.
  6.  
  7. Remove the camshaft sprocket, sprocket key, and timing chain from the engine.
  8.  
  9. Pry the crankshaft sprocket from the crankshaft.
  10.  

To install:
  1. If the engine has not been disturbed proceed to step Number 4 for installation procedures.
  2.  
  3. If the engine has been disturbed turn the crankshaft so that number one piston is at top dead center.
  4.  
  5. Temporarily install the sprocket key and the camshaft sprocket on the camshaft. Turn the camshaft so that the index mark of the sprocket is downward. Remove the key and sprocket from the camshaft.
  6.  
  7. Assemble the timing chain and sprockets. Install the keys, sprockets, and chain assembly on the camshaft and crankshaft so that the index marks of both the sprockets are aligned.
  8.  

It will be necessary to hold the spring loaded timing chain damper out of the way while installing the timing chain and sprocket assembly.

  1. Install the front oil slinger on the crankshaft with the inside diameter against the sprocket (concave side toward the front of the engine).
  2.  
  3. Install the fuel pump eccentric on the camshaft and the key, with the oil groove of the eccentric forward.
  4.  
  5. Install the distributor drive gear on the camshaft. Secure the gear and eccentric to the camshaft with the retaining washer and bolt.
  6.  
  7. Tighten the bolt to 40-55 ft. lbs. (54-75 Nm).
  8.  

6-226 Engine
  1. Remove the timing chain cover.
  2.  
  3. Before removing the parts, check for timing chain stretch. Press inward on the chain at a point midway between the gears. If the chain deflects more than 1 / 2 in. (13mm), it is overly stretched and must be discarded.
  4.  
  5. Bend up the lock tabs and the camshaft gear retaining bolt and remove the bolt.
  6.  
  7. Pry, alternately, behind each gear until both are free.
  8.  
  9. Inspect both gears. If either appears to be excessively worn, or if either are chipped or cracked, both gears and the chain must be replaced. If only the chain is defective, then, only the chain needs replacement. Inspect the cover. If it is bent or damaged, replace it.
  10.  

  1. Place the two gears into the chain so that there are exactly nine links, or ten pins, between the timing marks on the gears.
  2.  

  1. If either the camshaft or crankshaft was rotated while the gears were off, position the shafts so that the keyways are positioned as illustrated.
  2.  
  3. Slide the gears onto the shafts. If everything is aligned properly, the gears should slip into place with finger pressure.
  4.  
  5. If the camshaft has to be tapped into place, check that the camshaft bearing journals are not contacting the sides of Nos. 1, 5, or 9 tappets. This sometimes occurs when the camshaft is pushed backwards during gear installation. If this does occur, hold the camshaft forward to prevent tappet damage.
  6.  
  7. When the gears are fully seated, place the lock plate on the camshaft, with the tab in the hole of the gear.
  8.  
  9. Install the camshaft gear nut and tighten it to 40 ft. lbs. (54 Nm). Bend the lock plate to secure the nut.
  10.  
  11. Install the oil slinger on the crankshaft.
  12.  
  13. Install the remaining parts in reverse order of removal.
  14.  

6-230 Engine


Click image to see an enlarged view

Fig. Fig. 1: When the timing chain is properly tensioned, dimension (1) should be a minimum of 3.38 in. (85.9mm)

Special tools are needed for this job.

  1. Remove the timing chain cover. Measure across the gap between the chain sides. If the gap is less than 3.38 in. (85.85mm), the chain is stretched and should be replaced.
  2.  
  3. Install the camshaft sprocket remover tool as shown under the Cylinder Head Removal and Installation procedure.
  4.  
  5. Remove the sprocket with the tool as described under the cylinder head procedure.
  6.  
  7. Slide the chain from the sprocket.
  8.  
  9. Remove the chain tensioner pin to release tension on the tensioner blade. Remove the blade assembly and spring.
  10.  
  11. Remove the chain guide bracket.
  12.  
  13. The crank sprocket may now be removed.
  14.  
  15. Install the tensioner bracket on the front plate with the rubber covered leg positioned between the chain and the front plate.
  16.  
  17. Install the two capscrews and washers and two new 5 / 16 -24 seal nuts. Hold these seal nuts from turning when tightening the bolts.
  18.  
  19. Position the tensioner blade assembly and spring on the anchor stud on the front engine plate. Bend the blade so that the hook at the upper end of the spring is aligned with the notch in the top of the blade.
  20.  
  21. Insert the tensioner pin so that it engages the spring and blade. Position the top of the tensioner in the bracket.
  22.  
  23. Rotate the engine so that No. 1 piston is at TDC compression. Air will be forced out the spark plug hole when this occurs.
  24.  
  25. With the engine at Top Dead Center (TDC) on the No. 1 cylinder, the key ways in the crankshaft should be in the 12 o'clock position.
  26.  
  27. Temporarily install the camshaft sprocket and turn the camshaft until the nose of the No. 1 camshaft lobe, and the dowel hole on the camshaft, are pointing downward to the 6 o'clock position. Remove the sprocket.
  28.  
  29. Install a key in the crankshaft key way nearest the block.
  30.  
  31. Install the camshaft sprocket remover tool as before.
  32.  
  33. Position the chain on the sprockets so that the key way of the crank sprocket is up and the key way of the camshaft sprocket is down. The copper links of the chain should be aligned with the timing marks on the sprockets. When properly assembled, there should be 1 1 / 2 chain units, comprising 31 steel links between the copper links.
  34.  
  35. Lift the assembled chain and sprockets and slide the crank sprocket into position until it is fully seated.
  36.  
  37. Using the camshaft sprocket tool, tighten the nut to pull tension on the chain and align the sprocket with the end of the shaft. Push the sprocket off the tool and onto the shaft, aligning the key and key slot.
  38.  
  39. Position the fuel pump eccentric on the camshaft sprocket. Install the capscrew, lock washer and flat washer.
  40.  
  41. Remove the camshaft tool.
  42.  

 
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