John Deere — Grind Valve Seats (Two-Valve Head Engines)
Repair & overhaul · Cylinder head
From a John Deere service manual covering: 4045, 4045TF120, 6068, 6068 HF485, 6068HF158, 6068TF120, 6068TF250, 6068TFM50, 6068TFM76. Check it applies to your exact model before use.
Applies to: John Deere 4045, John Deere 4045TF120, John Deere 6068, John Deere 6068 HF485, John Deere 6068TF120, John Deere 6068TF250, John Deere 6068TFM50, John Deere 6068TFM76
Before you start
- Valve seat grinding should only be done by experienced personnel
- Do not grind excessively
Procedure
- Install appropriate pilot in valve guide bore.
- Install grinding stone on arbor and position onto valve seat.
- Grind valve seats to 30° seat angle.
- Measure seat width; reduce width with a narrowing stone if too wide.
- Check valve seat runout with an eccentrimeter if valve does not seat properly.
- Blend or radius all sharp edges after grinding.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Seat angle 30°
- Seat width 1.50—2.00 mm (0.059—0.079 in.)
- Maximum runout 0.08 mm (0.003 in.)
Full service-parts list: John Deere 4045 →, John Deere 6068 →, John Deere 6068 HF485 →, John Deere 6068TF250 →, John Deere 6068TFM50 →, John Deere 6068TFM76 →
Source: John Deere service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.