Chrysler Full-Size Trucks 1967-1988 Repair Guide

Valve Timing

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ADJUSTMENT



6-198 and 6-225 Engines
  1. Rotate the crankshaft until No. 6 exhaust valve is closing and No. 6 intake valve is opening.
  2.  
  3. Install a dial indicator so that the indicator pointer contact the valve spring retainer on the No. 1 intake valve parallel to the axis of the valve stem.
  4.  
  5. Turn No. 1 intake adjusting screw in one complete turn to remove the lash. Adjust the dial indicator to zero.
  6.  
  7. Rotate the crankshaft clockwise normal running direction until the valve has lifted 0.029 in. (0.73mm).
  8.  
  9. The timing of the crankshaft pulley should now read from 12° BTDC to TDC. Re-adjust lash.
  10.  

If the reading is not within specified limits, inspect the sprocket index marks, inspect the timing chain for wear, and inspect the accuracy of the "TDC'' mark on the timing indicator.

6-251 Engine
  1. Rotate the crankshaft until No. 1 exhaust valve is closing and No. 1 intake valve is opening.
  2.  
  3. Check the accuracy of the TDC mark by bring No. 6 piston up to TDC using a dial indicator placed in the opening provided in the cylinder head.
  4.  
  5. Set the valve lash on No. 6 intake to 0.027 in. (0.68mm).
  6.  
  7. Rotate the crankshaft clockwise until No. 6 intake tappet just contacts the valve stem.
  8.  
  9. The timing mark on the chain cover should read from 10° BTC to TDC; piston height should be read at 0.045 in. (1.1mm) BTC to 0°.
  10.  
  11. Reset the valve lash.
  12.  

6-243 Diesel

Valve timing is accomplished by aligning all gear timing marks.

V6 and V8 Gasoline Engines
EXCEPT 8-413 ENGINE
  1. Turn the crankshaft until the No. 6 exhaust valve is closing and the intake valve is opening.
  2.  
  3. Insert a 1 / 4 in. (25mm) spacer between the rocker arm pad and stem tip of No. 1 intake valve. Allow the spring load to bleed the tappet down.
  4.  
  5. Install a dial indicator so that the plunger contacts the valve spring retainer and nearly perpendicular as possible. Zero the indicator.
  6.  
  7. Rotate the crankshaft clockwise until the valve has lifted 0.010 in. (0.25mm) on the 8-318; 0.034 in. (0.86mm) on the 8-360; 0.025 in. (0.63mm) on the 8-383, 8-400 and 8-440.
  8.  


WARNING
Do not rotate the crankshaft any further, as serious damage will result!

  1. The ignition timing marks should now read anywhere from 10° BTDC to 2° ATDC.
  2.  
  3. If the reading is not within specifications, check for timing mark alignment, timing chain wear and the accuracy of the ignition timing indicator.
  4.  

8-413 ENGINE
  1. Check the accuracy of the TDC mark on the indicator plate by bringing the number one piston to TDC by means of an indicator placed in the spark plug openings.
  2.  
  3. Rotate the crankshaft clockwise (normal running direction) until No. 1 intake is fully open. Install a dial indicator No. 1 exhaust valve so that the indicator pointer contacts the spring retainer as near to 90° angle as possible.
  4.  
  5. Insert a 1 / 4 in. (25.6mm) spacer between rocker arm and stem of No. 1 exhaust valve. Allow spring load to bleed tappet down giving, in effect, a solid tappet.
  6.  
  7. Reset the dial indicator to zero. Rotate crankshaft counter-clockwise (opposite to normal running direction) until exhaust valve has lifted 0.090 in. (0.22mm).
  8.  
  9. The timing marks should now read from 12° BTDC to TDC. If the reading is over the specified limits, check timing gear marks and timing chain wear.
  10.  
  11. After timing has been checked, turn crankshaft clockwise (normal running direction) until tappet is back down to valve closed position. Remove spacer from between rocker arm and valve stem.
  12.  

 
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