Timing Belt Tracking Off-Center on 2JZ - Aftermarket Cam Gear Wear

Engineadvanced✓ OP Confirmed

Problem

Timing belt was not centered on the cam gears and was tracking/walking toward the back of the pulleys on a 2JZ engine. The belt had been running normally for 3 years before the issue appeared. The Gates blue timing belt appeared wobbly and off-center on aftermarket BC aluminum cam gears.

Timing belt not centered on cam gearsBelt tracking/walking toward the rear of the pulleysVisible wear marks showing where belt was originally running vs current positionBelt wobbling on the cam gearsScuff marks on PHR steel tensioner bracket brass insert

Root Cause

Aftermarket BC aluminum cam gears lost their hardness over time due to the softer aluminum material compared to OEM steel gears. The wear created an uneven surface that caused the timing belt to follow the wear to the lowest point, tracking off-center toward the back of the pulleys.

Confidence

Moderate confidence — Original poster confirmed this resolved the issue

View Original Thread →Posted March 2025 on SupraForums.com