Valve Shim Gauge Plate Kit
Date: April 5, 1995Reference: ITB95-013
Classifications: GI95-04
J38957-N VALVE SHIM GAUGE PLATE KIT
APPLIED VEHICLE: G20 (P10)
SERVICE INFORMATION
This procedure should be followed whenever a valve adjustment is needed on the SR20DE engine. You can also find this procedure as an April 1995 amendment to the EM section of the applied vehicle service manuals as follows:
Each cylinder contains two intake valves and two exhaust valves. Each pair of valves is operated by one Y-shaped rocker arm. One valve in each pair contains a rocker arm guide which is not adjustable. The matching valve contains a replaceable shim. A hydraulic lash adjuster (HLA) is also included in the system and acts as the rocker arm pivot.
The main purpose of the shims is to match the height of the shimmed valve(s) to the height of the non-adjustable rocker arm guide. The HLAs zero the valve lash.
J38957-N kit illustration
The following procedure will ensure that the proper size shim is installed on the shimmed valve to achieve "zero" valve clearance.
1. Remove camshafts, rocker arms and shims. For future reference, identify each shim with the cylinder it was removed from. Since the shims are reusable, it may riot be necessary to replace all of the existing shims.
2. Before attempting any measurement, make sure the valve, valve spring, collet, retainer and rocker arm guide are properly installed in the head.
3. Install the J38957-1 gauge plate into the tapped holes at the cam journals and secure it to the head using two of the hex bolts supplied with the kit. (The two remaining bolts are spares.)
4. Place the J38957-2 collar on the J38957-8 dial indicator. Make sure the dished side of the collar is facing 'up' (toward the dial indicator). Secure the collar to the dial indicator by tightening the set screw in the collar.
5. Place the indicator and collar over # 1 cylinder intake valve, shim side. Slide the tip of the dial indicator through the access hole and place it on the end of the valve stem. While resting the dial indicator collar on the gauge plate, 'zero' the dial indicator.
6. Move the dial indicator and collar to the adjacent hole in the gauge plate and place the tip of the indicator in the center of the rocker arm guide. Write down the dial indicator reading. This measured distance between the valve stem end and the contact surface of the rocker arm guide is the "T1" dimension.
7. Match the measured "T1" dimension (in inches) to the available shim chart (in millimeters) located in the S.D.S. section of the appropriate service manual. (The "T1" dimension is equivalent to the thickness and size designation of the valve shim.) Select the closest size shim to the measured "T1" dimension. For example, if the measured "T1" dimension is 0.1154 in. use a 2.925 mm shim. Shims are available in 17 different thicknesses ranging from 2.800 mm (0.110 in.) to 3.200 mm (0.126 in.) and increase in increments of 0.025 mm (0.001 in.). Refer to the NMC parts fiche for appropriate part numbers.
8. Repeat this procedure on the remaining cylinders.
This chart provides the part numbers for the most frequently ordered valve shims when performing a valve adjustment on the SR20DE engine.
Application Part Number
SR20DE 13229-53J00
13229-53J01
13229-53J02
13229-53J03
13229-53J04
13229-53J05
13229-53J06
13229-53J07
13229-53J08
13229-53J09
13229-53J10
13229-53J11
13229-53J12
While most dealers currently have these parts available, this lists the most commonly required shims to service the subject engines. With the continued availability of these parts you will be able to perform a valve adjustment in one day. This will eliminate the need to keep a customer's vehicle overnight.