Allis-Chalmers 2900 Mark II — Valve Face and Valve Seat Grinding
Repair & overhaul · Valves and valve seats
For the Allis-Chalmers 2900 Mark II, from the Allis-Chalmers service manual.
Before you start
- A negative angle must be avoided.
- Use valve grinder set according to the manufacturer's directions.
Procedure
- Before installing new or previously used valves, inspect valve seats in cylinder head for proper valve seating. Clean valve stems and grind valve faces to specified angle of 30 degrees.
- When new valve seat inserts are installed or previously used inserts reseated, refinishing must be done with a valve seat grinder set.
- Maintain cutting face of stone at correct angle and in proper condition by frequent dressing with a diamond wheel dresser.
- By grinding valve face and insert seat at slightly different angles, a fine line contact is obtained, eliminating the need to lap seating surfaces with grinding compound.
- The difference of angles is the interference angle, usually 0.5 to 1.5 degrees. The angle of insert seat is made greater than that of the valve face; for a 1 degree interference angle, dress insert se
Tools required
- Valve seat grinder Amazon
- Dial gauge Amazon
- Tool pilot Amazon
- Grinding wheels: 15, 30, 45, and 60 degrees Amazon
- Diamond wheel dresser Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Valve face angle: 30 degrees
- Interference angle: usually 0.5 to 1.5 degrees
- For 1 degree interference angle, insert seat grinder wheel dressed to 31 degrees
Source: Allis-Chalmers 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.