Usage:
G3406 (4FD, 1RK),
G3408 (6NB, 6RJ, 3WR, 8YR),
G3412 (7DB, 3NK, 6ZM, 9RR) Engines
Description of Change:
This article replaces the article titled "New Piston Cooling Jet Tube Assembly Provides Increased Piston Clearance" on Page 8 of the March 1998 issue of Engine News.
New piston cooling jet tube assemblies are used on these engines. These new tube assemblies provide more clearance between the tube assembly and the inside of the piston skirt than the former tube assembly. This increased clearance will prevent the new tube assembly from contacting the piston which could result in a broken tube assembly.
Also, on the G3406 Engines only, the cylinder block groups have been changed to allow the bolt that fastens the piston cooling jet tube assembly to the cylinder block to be changed from a 3/8 inch bolt to a 7/16 inch bolt. The new 7/16 inch bolt has a machined flat that allows an increased oil flow from the piston cooling jet tube assembly.
Adaptable To: The new 155-4010 Piston Cooling Jet Tube Assembly is a direct replacement for the former 6I-2992 Piston Cooling Jet Tube Assembly in the above engines. The former tube assembly is canceled. The chart lists the adaptability of the new 155-4010 Piston Cooling Jet Tube Assembly.
For G3406 Engines ONLY, the 110-2099 Cylinder Block Group has been changed to use 151-5925 Bolts (7/16 inch), instead of the 7E-6479 Bolts (3/8 inch), to fasten the piston cooling jet tube assemblies to the cylinder block. This change is effective at the same time as the new 155-4011 Piston Cooling Jet Tube Assembly (which replaces the former 6I-2992 Piston Cooling Jet Tube Assembly). The new 155-4011 Piston Cooling Jet Tube Assembly is effective with G3406 Engines (4FD1158-Up and 1RK87-Up).