Procedure
Cut Exhaust Valve GuidesIMPORTANT:
For the following procedures, refer to "SOHC (LKO) Cylinder Head" section of the 1991-1994 Engine Mechanical Service Manual or "SOHC (L24) Cylinder Head" section of the 1995 Engine/Fuel/Air Intake/Exhaust Service Manual, depending on year of vehicle.
1. Remove cylinder head assembly.
2. Remove complete rocker arm assembly and all hydraulic lifters.
3. Remove and discard exhaust valves, and seals. (Reuse exhaust valve springs, caps, keys and hydraulic lifters. Do not remove intake valves, springs or seals.)
4. Clean carbon and varnish from the inside diameter of all the valve guides using a metal or nylon valve guide brush driven by an electric drill and solvent.
5. Using Saturn Valve Guide Go/No-Go Gauge (J43120), measure exhaust valve guides.
NOTICE:
The Go (green) end of gauge should go through entire length of valve guide with light and uniform pressure. Use of excessive force will result in tool and/or guide damage.
6. Insert Go (green) end of gauge into valve guide from either the combustion chamber side or the camshaft side.
^ If gauge passes through guide with light and uniform pressure, proceed to step b.
^ If gauge will not pass through guide with light and uniform pressure, clean guide again as in step 4 and repeat guide measurement. If gauge still will not pass through guide, refer to the appropriate model year Saturn Engine/Fuel/Air Intake/Exhaust Service Manual for valve guide repair and/or replacement procedures.
NOTICE:
The No-Go (red) end of gauge should NOT enter either end of valve guides. Use of excessive force Will result in tool and/or guide damage.
1). Attempt to insert No-Go (red) end of gauge into both ends of valve guides.
^ If gauge does not enter either end of guide, then guide is within correct specifications for diameter, straightness, and roundness.
^ If gauge enters either end of guide, the guide is oversized beyond specifications. Refer to the appropriate model year Saturn Engine/Fuel/Air Intake/Exhaust Service Manual for valve guide repair and/or replacement procedures.
6. Place cylinder head, with combustion chamber side facing up, on 2 x 4 wood blocks on the shop floor or suitable workbench.
IMPORTANT:
Review the following information before using the SA9704B, Valve Guide End Mill Cutter W/Stop Collar:
^ Use a 1/2 horsepower variable or low speed electric drill motor,
^ Use SOHC (blue) plastic stop collar,
^ Stop collar must be located so that the set screw aligns with end mill groove,
^ DO NOT use cutting fluid,
^ Use drill speed of approximately 500 rpm,
^ Apply pressure straight onto valve guide,
^ DO NOT side load tool during operation,
^ Some smoke may occur during the cutting process, (this is normal and tool life is not affected).
7. Using service tool 5A9740E (Valve Guide End Mill Cutter) with SOHC (blue) plastic stop collar, cut the exhaust valve guides from the combustion chamber side. The plastic stop will make contact with the valve seat when the end mill has completed the specified amount of guide removal (approximately 10 mm [3/8 in.]). (Refer to illustration.)
8. Clean the valve guide debris, created from the cutting operation, from the cylinder head with solvent.
IMPORTANT:
Do not use a reamer as a cleaning tool. Machine/drill driven reamers typically need a minimum of .0762 mm (0.003 in.) material cut to operate correctly and to create the desired surface finish. Attempting to use a machine/drill operated reamer without removing material may cause the reamer to bind, will burnish/smear instead of cutting the guide material and will result in decreased tool life.
9. Clean carbon deposits from the valve seat surface with solvent and a 3M(R) Scotch-Brite fiber pad (or equivalent).
IMPORTANT:
Some carbon deposits and minor pitting on the valve seat is normal. If deposits or pitting is excessive, valve seat refacing or replacement should be performed by a qualified machine shop.
10. Install new:
^ Exhaust Valve Oil Seals (P/N 21006516 - 1991-1994 LKO engines or P/N 21006515 - 1995 L24 engines)
^ Exhaust Valves (P/N 21007040)
11. Install cylinder head assembly.
12. Verify the condition has been repaired by:
a. Start engine and increase engine speed to 3500 rpm.
b. Hold engine rpm at 3500 rpm for approximately 30 seconds.
c. Release accelerator, allowing engine to return to idle rpm and observe for engine miss or - popping noise. It may be necessary to repeat this step throughout the entire engine warm-up cycle until normal operating temperature of 88°C (190°F) is achieved.