EGR Valve/Engine - Piston Slap Noise
84ford17Article No. 83-23-14-S
NOISE - PISTON SLAP - (4.9L) COLD DRIVEAWAY UNDER LIGHT LOAD
- VEHICLES UNDER 8500 LB. GVW
LIGHT TRUCKS 1981-83 E & F-SERIES & BRONCO
CALIBRATIONS: All (3-52F, 3-52G, 3-52K, 3-52S, 3-52T, 3-52V should only use Step B)
This is a re-issue and supplement to TSB 83-23-14, dated November 15, 1983. Revised pistons are now available in .020, .030 and .040 oversize for use in engine overhauls.
Some units may experience a piston slap noise during cold engine high speed and light load conditions. The noise will usually occur within the first 2 miles of operation. The following procedures should resolve this concern. Perform vacuum schematic changes as noted for cold drive trickle EGR. Then, if necessary, replace pistons if the concern is not resolved.
Step A
All 1981-83 vehicles except 1983 AOD calibrations 3-52F, 3-52G, 3-52K, 3-52S, 3-52T, 3-52V. These calibrations should only use Step B.
FIGURE 36:
1. Assemble a vacuum harness as shown in Figure 36.
2. Locate the EGR valve and remove the vacuum hose from the valve and connect it to the "C" end of the harness assembly.
3. Connect the "B" end of the harness assembly to the EGR valve.
4. Remove the hose from the carburetor EGR port and connect the "A" end of the harness to the EGR port.
5. Connect the hose that was removed from the EGR port to the other side of the "A" end of the harness.
FIGURE 37:
6. Verify correct vacuum routing using the vacuum schematic (Figure 37).
Step B
If the above procedure does not resolve the concern, replace the pistons with the revised pistons listed in the Parts List.
NOTE: As stated in the 1982 & 1983 Light Truck Engine Shop Manual, page 21-11-37, piston to bore clearance must be .0014 to .0022 and all procedures from Section 21-01 must be performed prior to new piston installation.
Obtain an Authorized Modifications decal and list the date, dealer number and summary of alterations performed. Select a prominent place adjacent to the Vehicle Emission Control Information decal suitable for installing the Authorized Modifications decal. Clean the area, install the decal and cover it with a clear plastic decal shield.
MODEL
PART NUMBER PART NAME YEAR CLASS
E2TZ-6108-A Piston Pin Assy. (Red) 1981-82 A
E2TZ-6108-B Piston Pin Assy. (Blue) 1981-82 B
E2TZ-6108-C Piston Pin Assy. 1981-82 B
(Yellow - .003 over)
E2TZ-6108-D Piston Pin Assy. 1981-82 C
(.020 Over)
E2TZ-6108-E Piston Pin Assy. 1981-82 C
(.030 Over)
E2TZ-6108-F Piston Pin Assy. 1981-82 C
(.040 Over)
E4TZ-6108-A Piston Pin Assy. (Red) 1983 B
E4TZ-6108-B Piston Pin Assy. (Blue) 1983 B
E4TZ-6108-C Piston Pin Assy. 1983 B
(Yellow - .003 over)
E4TZ-6108-D Piston Pin Assy. 1983 C
(.020 Over)
E4TZ-6108-E Piston Pin Assy. 1983 C
(.030 Over)
E4TZ-6108-F Piston Pin Assy. 1983 C
(.040 Over)
373846-S Tee B
D3TZ-12A091-C Vacuum Dealer Valve A
D0PZ-12226-B Hose-Rubber 5/32" ID AG
OTHER APPLICABLE ARTICLES: SEN 83-15; 83-23-14
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: 6149A
TIME: F-Series & Bronco - 7.5 Hrs. Econoline - 8.3 Hrs. DLR. CODING: Basic Part No. 6108 Code: 56