Engine - Valve Noise or Poor Performance
Models: 1991 G20Section: Engine Mechanical
Classification: EM92-001
Bulletin No.: ITB92-004
Date: January 23, 1992
G20 CAM LOBE WEAR
APPLIED MODEL:
All 1991 G20 (P10)
APPLIED VIN:
JNKCP01P*NT303833 (Engine No. SR20-201099)
SERVICE INFORMATION:
Some owners of 1991 G20 vehicles may complain of engine valve train noise or poor performance. If all the usual component tests are within the proper specifications, inspection of the camshafts may reveal a worn cam lobe.
SERVICE PROCEDURE:
Beginning on page EM-19 of the Service Manual
1. Remove the rocker cover and press down on each rocker arm by hand to detect excess free movement in the hydraulic lash adjuster. Less than 1 mm movement is normal.
2. Rotate the crankshaft and inspect the lobes for wear.
3. If wear is found bring the No. 1 piston to TDC and align the matching marks on the timing chain and cam sprockets. Remove the chain tensioner.
4. Remove the distributor. Do not turn the rotor once removed. Make note of the position of the distributor and camshaft for the purpose of reassembly. The position should be as shown.
5. Remove the timing chain guide.
6. Remove the camshaft sprockets.
NOTE:
Maintain the valve train components in their original relative positions as they will need to be installed in their original positions during assembly.
7. Remove the camshafts and inspect cam lobes, rocker arms, hydraulic lash adjusters (HLA's), and valve shims for scratches or wear. Refer to pages EM-45 and 46 of the service manual.
Reassemble
8. Replace damaged camshafts, rocker arms, HLA's and shims as necessary.
9. Using special tool, Kent-Moore P/N J38957, check the valve shim heights and adjust as necessary. If you need this tool call Kent-Moore directly at (800) 345-2233.
10. Check camshaft journal diameters and end play, see page EM-41 of the service manual.
11. Reassemble other components in the reverse order, be certain that the chain tensioner arrow points to the front of the engine as illustrated. Consult the Service Manual for valve timing, ignition timing, and fastener torque specifications.
12. Start engine and bring to operating temperature.
13. Replace engine oil (5W-30) and filter.
PARTS INFORMATION:
PART DESCRIPTION PART NUMBER
Exhaust Camshaft 13020-78E10
Intake Camshaft 13020-64Y00
WARRANTY INFORMATION: