Valve Seat Replacement
WARNING: This page is about a different car, the 2020 Infiniti QX60. However, it is still accessible from the selected car via links, so may be relevant.
- Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess in cylinder head. Set the machine depth stop to ensure this.
- Ream cylinder head recess for service valve seat.
Oversize
: 0.5 mm (0.020 in)
Intake
: 38.500 - 38.516 mm (1.5157 - 1.5164 in)
Exhaust
: 32.100 - 32.116 mm (1.2638 - 1.2644 in)
Be sure to ream in circles concentric to the valve guide center.
This will enable valve seat to fit correctly.
- Heat cylinder head to 110 - 130 deg. C (230 - 266 deg. F) by soaking in heated oil.WARNING: Cylinder head contains heat. When working, wear protective equipment to avoid getting burned.
- Press fit valve seat until it seats on the bottom.
- Cut or grind valve seat using suitable tool to the specified dimensions. Refer to Cylinder Head .
- After cutting, lap valve seat with abrasive compound.
- Check valve seating condition.
Seat face angle (±)
: 45 deg. 15' - 45 deg. 45' degrees/minutes
Contacting width (W) for intake
: 1.18 - 1.22 mm (0.0465 - 0.0480 in)
Contacting width (W) for exhaust
: 1.38 - 1.42 mm (0.0543 - 0.0559 in)
- Use a depth gauge to measure the distance between the mounting surface of the cylinder head spring seat and the valve stem end. If the distance is shorter than specified, repeat step 5 to adjust it. If it is longer, replace the valve seat with a new one.
Valve seat resurface limit (L) intake
: 41.16 - 41.76 mm (1.6205 - 1.6441 in)
Valve seat resurface limit (L) exhaust
: 41.09 - 41.69 mm (1.6177 - 1.6413 in)