Jeep CJ 1945-1970 Repair Information

Valves and Springs

Print

Fabricate a valve arrangement board to use when you remove the valves, which will indicate the port in which each valve was originally installed (and which cylinder head on the V6 engine). Also note that the valve keys, rotators, caps, etc. should be arranged in a manner which will allow you to install them on the valve on which they were originally used.

REMOVAL

Valves Installed in Cylinder Head

See Figures 1, 2 and 3



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the valve train utilized by the 6-230 engine



Click image to see an enlarged view

Fig. Fig. 2: Invert the cylinder head and withdraw the valve from the cylinder head bore



Click image to see an enlarged view

Fig. Fig. 3: A wire wheel may be used to clean the combustion chambers of carbon deposits

  1. The head must be removed from the engine.
  2.  

In all but the 4-134, all the valves are in the head. In the 4-134, just the intakes are in the head. The exhaust valves are in the block.

  1. Remove the rocker arm assemblies.
  2.  
  3. Using a spring compressor, compress the valve springs and remove the keepers (locks). Relax the compressor and remove the washers or rotators, the springs, and the lower washers (on some engines). Keep all parts in order.
  4.  

Valves Installed in Engine Block
4-134 ENGINE

See Figures 4, 5 and 6



Click image to see an enlarged view

Fig. Fig. 4: Remove the side cover retaining bolts/breather assemblies ...



Click image to see an enlarged view

Fig. Fig. 5: ... then pull the side cover off of the engine block



Click image to see an enlarged view

Fig. Fig. 6: Once the cover is removed, access to the springs can be gained

  1. Remove the attaching bolts from the side valve spring cover. Remove the side valve spring cover and gasket.
  2.  
  3. Use rags to block off the three holes in the exhaust chamber to prevent the valve retaining locks from falling into the crankcase should they be accidentally dropped.
  4.  
  5. Using a valve spring compressor, compress the valve springs only on those valves which are in the closed position (valve seated against the head). Remove the valve spring retainer locks, the retainer, and the exhaust valve spring. Close the other valves by rotating the camshaft and repeat the previous steps for the remaining valves.
  6.  
  7. Lift all of the valves from the cylinder block. If the valve cannot be removed from the block, pull the valve upward as far as possible and remove the spring. Lower the valve and remove any carbon deposits from the valve stem. This will permit removal of the valve.
  8.  

6-226 ENGINE
  1. Remove the cylinder head.
  2.  
  3. Remove the valve chamber cover from the side of the block. Look for evidence of oil seepage past the cover bolt seals.
  4.  
  5. Remove the two valve tappet oil shields. They are held in place by spring clips and may be lifted out with your fingers, or pried out.
  6.  
  7. Use shop rags to block off the holes in the valve chamber, to prevent the valve locks from falling into the crankcase.
  8.  
  9. Using a spring compressor on those valves which are closed compress the valve springs and remove the locks. Relax the compressor and remove the retainer and spring. Lift the valve from the block and mark it for assembly. Rotate the crankshaft and close each valve in turn, performing the removal procedure.
  10.  

INSPECTION & REFACING



See Figures 7, 8 and 9



Click image to see an enlarged view

Fig. Fig. 7: A dial gauge may be used to check valve stem-to-guide clearance



Click image to see an enlarged view

Fig. Fig. 8: Valve stems may be rolled on a flat surface to check for bends



Click image to see an enlarged view

Fig. Fig. 9: Use a micrometer to check the valve stem diameter

  1. Clean the valves with a wire wheel.
  2.  
  3. Inspect the valves for warping, cracks or wear.
  4.  
  5. The valves may be refaced if not worn or pitted excessively.
  6.  
  7. Using a valve guide cleaner chucked into a drill, clean all of the valve guides. Check the valve stem diameter and the guide diameter with micrometers. Valve guides on the 4-134, 6-226 and 6-230 are replaceable. On the other engines, the guide must be reamed and an insert pressed in, or they may be knurled to bring up interior metal, restoring their diameter. Oversized valve stems are available to compensate for wear.
  8.  
  9. Install each valve into its respective port (guide) of the cylinder head.
  10.  
  11. Mount a dial indicator so that the stem is at 90 degrees to the valve stem, as close to the valve guide as possible.
  12.  
  13. Move the valve off its seat, and measure the valve guide-to-stem clearance by rocking the stem back and forth to actuate the dial indicator.
  14.  
  15. In short, the refacing of valves and other such head work is most easily done at a machine shop. The quality and time saved easily justifies the cost.
  16.  
  17. Inspect the springs for obvious signs of wear. Check their installed height and tension using the values in the Valve Specifications Chart in this section.
  18.  

REFACING



Using a valve grinder, resurface the valves according to specifications in this section.

All machine work should be performed by a competent, professional machine shop.


CAUTION
Valve face angle is not always identical to valve seat angle. A minimum margin of1/32in. (0.794mm) should remain after grinding the valve. The valve stem top should also be squared and resurfaced, by placing the stem in the V-block of the grinder, and turning it while pressing lightly against the grinding wheel. Be sure to chamfer the edge of the tip so that the squared edges do not dig into the rocker arm or camshaft.

LAPPING



This procedure should be performed after the valves and seats have been machined, to insure that each valve mates to each seat precisely.

  1. Invert the cylinder head, lightly lubricate the valve stems, and install the valves in the head as numbered.
  2.  
  3. Coat valve seats with fine grinding compound, and attach the lapping tool suction cup to a valve head.
  4.  

Moisten the suction cup.

  1. Rotate the tool between your palms, changing position and lifting the tool often to prevent grooving.
  2.  
  3. Lap the valve until a smooth, polished seat is evident.
  4.  
  5. Remove the valve and tool, and rinse away all traces of grinding compound.
  6.  

VALVE SPRING TESTING



See Figures 10 and 11



Click image to see an enlarged view

Fig. Fig. 10: Use a caliper gauge to check the valve spring free-length



Click image to see an enlarged view

Fig. Fig. 11: Check the valve spring for squareness on a flat surface; a carpenter's square can be used

Place the spring on a flat surface next to a square. Measure the height of the spring, and rotate it against the edge of the square to measure distortion. If spring height varies (by comparison) by more than 1 / 16 in. (1.588mm) or if distortion exceeds 1 / 16 in. (1.588mm), replace the spring.

In addition to evaluating the spring as indicated earlier, test the spring pressure at the installed and compressed (installed height minus valve lift) height using a valve spring tester. Spring pressure should be within 1 lb. (2.2kg) of all other springs in either position.

INSTALLATION



  1. Coat all parts with clean engine oil. Install all parts in their respective locations. The spring is installed with the closely wound coils toward the valve head. Always use new valve seals.
  2.  
  3. Use a spring compressor to install the keepers and slowly release the compressor after the keepers are in place.
  4.  

Coat the locks, on the 6-226, with chassis grease to hold them in place until you release the spring compressor.

  1. Release the spring compressor. Tap the end of the stem with a wood mallet to insure that the keepers are securely in place.
  2.  
  3. Install all other parts in reverse order of removal.
  4.  

 
label.common.footer.alt.autozoneLogo