- Engine:
- 3406B (S/N: 8TC1-UP; 3ZJ1-UP; 2EK1-UP; 4CK1-UP)
- 3406C (S/N: 3ZJ1-UP; 4CK1-UP)
Part number 346-3340 Top Piston Ring is now used for all applications that use an aluminum piston in the engines that are listed above. The new 346-3340 Top Piston Ring is adaptable back to the first production of the listed engines. The difference between the new 346-3340 Top Piston Ring, and the existing, 134-3761 Top Piston Ring is an increased ring gap of 0.200 mm (0.00787 inch). The increased ring gap allows proper clearance during high temperatures that are experienced with high load factor applications.
All of the 3400 piston cylinder pack prints that include the larger ring gap were updated on July 6, 2010 with an effective date of March 1, 2011. The effective date for cylinder packs built in the United States with the 346-3340 Top Piston Ring was March 15, 2011. Dealers receiving cylinder packs built in the United States with package date codes before March 15 2011 should change the top ring before installing the cylinder packs. Cylinder packs built in China have an effective date of December 19, 2011. Dealers receiving cylinder packs built in China with package date codes before December 19 should change the top ring before installing the cylinder packs.