- Engines:
- 3606 (S/N: 8RB680-UP)
- 3608 (S/N: 1ZD1-UP; 5PG106-UP; 6MC556-UP; 7WR16-UP; 8LL11-UP)
- 3612 (S/N: 2NZ176-UP; 9FR21-UP; 9RC332-UP)
- 3616 (S/N: 1FN150-UP; 1PD379-UP)
Description of Change: New air shutoff groups are used on these engines. The new air shutoff groups have a completely new design. These new air shutoff groups can be installed back to first production of the above engines.
Adaptable To: The new 150-7891 Air Shutoff Group is effective with the above In-Line engines. The 150-7891 Air Shutoff Group includes the new 150-7931 Air Shutoff Group. The new 193-4652 Air Shutoff Group is effective with the above Vee engines. The new 193-4652 Air Shutoff Group includes the new 176-1383 Air Shutoff Group. All of these new air shutoff groups are available for service at the group level. All of the serviceable components of the new air shutoff groups are identified in the Service Information System (SIS).
Note: For consistent operation, the supply pressure to the air shutoff group should be above 1100 kPa (160 psi). The maximum allowable supply pressure is 1720 kPa (250 psi).After the new air shutoff group is installed, the new air shutoff group must be exercised by operation. The new air shutoff group must be operated after every 150 hours of service or the air shutoff group must be operated weekly.