Valve, Springs, Valve Seals, Stems, Guides and Seats
Valves, Springs and Valve Seals RemovalSpecial Tools Required
- Valve spring compressor attachment 07757-PJ1010A
Identify the valves and valve springs as they are removed so that each item can be reinstalled in its original position.
1. Remove the cylinder head.
2. Using an appropriate-sized socket (A) and plastic mallet (B), lightly tap the valve retainer to loosen the valve keepers.
3. Install the spring compressor. Compress the spring and remove the valve keepers.
4. Install the valve guide seal remover.
5. Remove the valve seal.
Valve Inspection
1. Remove the valves.
2. Measure the valve in these areas.
Valve Stem-to-Guide Clearance Inspection
1. Remove the valves.
2. Slide the valve out of its guide about 10 mm, then measure the guide-to-stem clearance with a dial indicator while rocking the stem in the direction of normal thrust (wobble method).
- If the measurement exceeds the service limit, recheck it using a new valve.
- If the measurement is now within the service limit, reassemble using a new valve.
- If the measurement with a new valve still exceeds the service limit, go to step 3.
3. Subtract the O.D. of the valve stem, measured with a micrometer, from the I.D. of the valve guide, measured with an inside micrometer or ball gauge. Take the measurements in three places along the valve stem and three places inside the valve guide. The difference between the largest guide measurement and the smallest stem measurement should not exceed the service limit.
Intake Valve Stem-to-Guide Clearance:
Standard (New): 0.02 - 0.05 mm (0.001 - 0.002 inch)
Service Limit: 0.08 mm (0.003 inch)
Exhaust Valve Stem-to-Guide Clearance:
Standard (New): 0.05 - 0.08 mm (0.002-0.003 inch)
Service Limit: 0.11 mm (0.004 inch)
Valve Guide Replacement
Special Tools Required
- Valve guide driver, 5.5 mm 07742-0010100
- Valve guide reamer, 5.5 mm 07HAH-PJ7010B
1. Inspect valve stem-to-guide clearance.
2. As illustrated, use a commercially available air-impact valve guide driver (A) modified to fit the diameter of the valve guides. In most cases, the same procedure can be done using the special tool and a conventional hammer.
3. Select the proper replacement guides, and chill them in the freezer section of a refrigerator for about an hour.
4. Use a hot plate or oven to evenly heat the cylinder head to 300°F (150°C). Monitor the temperature with a cooking thermometer. Do not get the head hotter than 300°F (150°C); excessive heat may loosen the valve seats.
5. Working from the camshaft side, use the driver and an air hammer to drive the guide about 2 mm (0.1 inch) towards the combustion chamber. This will knock off some of the carbon and make removal easier. Hold the air hammer directly in line with the valve guide to prevent damaging the driver.
6. Turn the head over and drive the guide out toward the camshaft side of the head.
7. If a valve guide won't move, drill it out with a 8 mm (5/16 inch) bit, then try again. Drill guides only in extreme cases; you could damage the cylinder head if the guide breaks.
8. Remove the new guide(s) from the freezer, one at a time, as you need them.
9. Apply a thin coat of clean engine oil to the outside of the new valve guide. Install the guide from the camshaft side of the head; use the special tool to drive the guide in to the specified installed height (A) of the guide (B). If you have all 16 guides to do, you may have to reheat the head.
10. Coat both reamer and valve guide with cutting oil.
11. Rotate the reamer clockwise the full length of the valve guide bore.
12. Continue to rotate the reamer clockwise while removing it from the bore.
13. Thoroughly wash the guide in detergent and water to remove any cutting residue.
14. Check the clearances with a valve. Verify that a valve slides in the intake and exhaust valve guides without exerting pressure.
Valve Seat Reconditioning
1. Inspect valve stem-to-guide clearance. If the valve guides are worn, replace them before cutting the valve seats.
2. Renew the valve seats in the cylinder head using a valve seat cutter.
3. Carefully cut a 45° seat, removing only enough material to ensure a smooth and concentric seat.
4. Bevel the upper and lower edges at the angles shown in the illustration. Check the width of the seat and adjust accordingly.
5. Make one more very light pass with the 45° cutter to remove any possible burrs caused by the other cutters.
6. After resurfacing the seat, inspect for even valve seating: Apply Prussian Blue compound (A) to the valve face. Insert the valve in its original location in the head, then lift it and snap it closed against the seat several times.
7. The actual valve seating surface (B), as shown by the blue compound, should be centered on the seat.
- If it is too high (closer to the valve stem), you must make a second cut with the 67.5° cutter to move it down, then one more cut with the 45° cutter to restore seat width.
- If it is too low (close to the valve edge), you must make a second cut with the 40° cutter (intake side) or the 30° cutter (exhaust side) to move it up, then make one more cut with the 45° cutter to restore seat width.
NOTE: The final cut should always be made with the 45° cutter.
8. Insert the intake and exhaust valves in the head and measure valve stem installed height (A).
9. If valve stem installed height is over the service limit, replace the valve and recheck. If it is still over the service limit, replace the cylinder head; the valve seat in the head is too deep.
Valves, Springs and Valve Seals Installation
Special Tools Required
- Valve spring compressor attachment 07757-PJ1010A
1. Coat the valve stems with engine oil. Install the valves in the valve guides.
2. Check that the valves move up and down smoothly.
3. Install the spring seats on the cylinder head.
4. Install the new valve seals (A) using the valve guide seal installer (B).
NOTE: The exhaust valve seal (c) has a black spring (D), and the intake valve seal (E) has a white spring (F). They are not interchangeable.
5. Install the valve spring and valve retainer. Place the end of the valve spring with closely wound coils toward the cylinder head.
6. Install the valve spring compressor. Compress the spring and install the valve keepers.
7. Lightly tap the end of each valve stem two or three times with a plastic mallet (A) to ensure proper seating of the valve and valve keepers. Tap the valve stem only along its axis so you do not bend the stem.
Camshaft Gear Installation
1. Install the camshaft gear (A).
2. Apply engine oil to the threads of the camshaft gear mounting nut (B), then install it.
3. Hold the camshaft with an open-end wrench. then tighten the camshaft gear mounting nut.