Subaru Coupes/Sedans/Wagons 1985-1996 Repair Guide

Valve Guides



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: Valve guide protrusion

Replacing the valve guides involves heating the head to high temperatures and driving the old guide out with the use of special tools. The head may have to be machined for an oversize guide if the bushing bore dimension is over the standard specifications. The new guide is then reamed for the proper valve stem-to-guide clearance. This repair requires a high level of mechanical skill and should only be performed by a reputable machine shop.

Valve guides which are not excessively worn or distorted may, in some cases, be knurled rather than replaced. Knurling is a process in which metal inside the valve guide bore is displaced and raised, thereby reducing clearance. The possibility of knurling rather than replacing the guides should be discussed with a machinist.

  1. Remove the cylinder head.
  3. Remove the valve springs, keepers, retainers and oil seals.
  5. Mount a dial indicator at a 90° angle to the valve stem. With the valve lifted off the seat, wiggle the valve and measure the valve-to-stem clearance.
  7. If not within specification, remove the valve and measure the valve stem diameter. If valve stem diameter is not within specification, replace the valve.
  9. If the valve stem diameter is within specification, the valve guide is worn and must be replaced.
  11. Drive the valve guide out using a valve guide remover.
  13. Ream the cylinder head to provide the necessary interference fit for the new valve guide. Check with the manufacturer for specifications.
  15. Install the new valve guide using a valve guide installation tool. The valve guide should project as follows:

    1.2L Engine: 0.807 in. (20.5mm) intake; 0.807 in. (20.5mm) exhaust.
    1.6L Engine : 0.708 in. (18mm) intake; 0.905 in. (23mm) exhaust.
    1.8L Engine: 0.709 in. (18mm) intake; 0.709 in. (18mm) exhaust.
    2.2L Engine: 0.699 in. (17.8mm) intake; 0.699 in. (17.8mm) exhaust.
    2.5L Engine: 0.699 in. (17.8mm) intake; 0.699 in. (17.8mm) exhaust.
    2.7L Engine : 0.690 in. (17.5mm) intake; 0.690 in. (17.5mm) exhaust.
    3.3L Engine: 0.335 in. (8.5mm) intake; 0.335 in. (8.5mm) exhaust.

  17. Ream the inside of the valve guide to provide the required oil clearance for the valve.
  19. Install the valve, oil seal, spring, retainer and keeper.
  21. Reassemble the cylinder head and install.