Jeep CJ 1945-1970 Repair Information

Valve Timing

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L4-134 ENGINES BEFORE NO. 175402 IN CJ-2A MODELS



See Figures 1 and 2



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Fig. Fig. 1: View of the timing marks located on the flywheel and as seen through the view hole in the engine case-L4-134 engines before no. 175402



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Fig. Fig. 2: Make certain that the timing gear marks are aligned as shown

  1. Turn the crankshaft so that pistons Nos. 1 and 4 are positioned at Top Dead Center (TDC) as indicated by the TC mark on the flywheel seen through the timing hole in the right side of the flywheel housing.
  2.  
  3. 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.
  4.  
  5. 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.
  6.  

L4-134 ENGINES AFTER ENGINE NO. 175402 AND ALL F4-134 ENGINES



See Figures 3, 4 and 5



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Fig. Fig. 3: View of the timing marks located on the flywheel and as seen through the view hole in the engine case-L4-134 engines after no. 175402 and all F4-134 engines



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Fig. Fig. 4: If a replacement engine block was installed along with the original flywheel, the mounting flange on the engine must be cut away



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Fig. Fig. 5: Make certain, when installing the timing gears or setting the engine at TDC, that the timing marks are as close to each other as possible (as shown)

  1. Install the timing gears with the marks aligned as shown.
  2.  
  3. Set the intake valve clearance to 0.020 in. (0.5mm) on the No. 1 cylinder.
  4.  
  5. Rotate the crankshaft until the No. 1 cylinder intake valve is ready to open as indicated by the IO mark on the flywheel. The mark should be centered in the hole.
  6.  

Some later models do not have an IO mark. TC and 5 degrees are the only marks. On these engines, the intake valve opens at 9 degrees BTC. To estimate valve opening, measure the distance between TC and 5 degrees and measure about that distance further on. On CJ-3A models beginning with engine No. 130859, a 41/2in. (114.3mm) starter motor was used. To use the larger starter, it was necessary to increase the width of the cylinder block flange, partially covering the flywheel hole. This makes it impossible to use the hole for timing purposes. In this event, use the timing marks on the crankshaft pulley. If a replacement block is installed with the later design in a vehicle originally equipped with the earlier design timing marks, it will be necessary to cut away enough of the flange to allow a view of the timing marks, as no other timing marks exist on the these early engines.

 
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