Toyota 3.4LV65VZ-FE engine (hereinafter referred to as 3.4 engine) since its introduction in 1995 has been widely used, has been carried in the Toyota T100, compact Tacoma pickup, 4RunnerSUV and full-size Tundra pickup and other models. In this paper, 3.4 engine as an example, a brief introduction to the timing of the belt replacement process.
    Regular inspection, timely replacement
    For the 3.4 engine timing belt, the Toyota expert's advice is: the vehicle travels 100,000 km when doing a thorough inspection, 150,000 km when forced replacement. Although the 3.4 timing belt (also the pump belt) can be completely trouble-free operation of more than 150,000 km, but Toyota experts still insist on the timing of the timing of the timing of inspection, timely replacement. Normally, the pump is always "retired" (relative to the timing belt) ahead of time, and it is important to ensure that the timing belt is replaced at the same time when replacing the pump. In addition, when the need to open the front of the engine, be sure to fully test the crankshaft and camshaft oil seal to prevent leakage.
    Compression process of tension wheel tappet
    3.4 Timing The automatic tensioning device installed in the belt is located at the lower right of the engine (relative to the occupant). The pressing of the tappet is the first step in the entire timing belt replacement process, and the proper way Timing belt replacement speed and quality, play a decisive role. Specific methods are the following two kinds. Method 1: The tensioner assembly can be removed from the vehicle and then pressed on the work vise. But it is necessary to remove the air-conditioning compressor bracket in order to loosen the tensioning device fastening bolts, the whole process takes about 1h. Method 2: Use a special Schley compression tool (part number: 97300) in the car on the compression operation (ie, removal). The Schley compression tool meets the space requirements between the tensioner and the pump pulley, and only the nut is tightened to complete the clamping operation. When the tappet is compressed to a sufficient stroke, the sliding locking pin, which is used in conjunction with the tool, is inserted into the locking hole to ensure that the tappet is securely locked until the timing belt is replaced and the locking pin is removed as required , Reset the tappet.
    Precautions for timing belt replacement
    First of all, to know the use of vehicles and check the engine noise. If a strange "click" sound is heard near the top of the timing belt cover and the noise is reduced after the engine is adjusted but still present, it can be determined that the typical tensioning device is broken. Before pressing the tappet, check the tensioning device. At this point the hand to try to press the tension wheel, if the tappet stroke only 1/8 "~ 1/4" (3.1mm ~ 6.3mm), you need to replace the tension device assembly.
    Second, the tappet compression process operation should be slow should not be anxious. For example, rotate the Schee compression tool tightening nut 1/8 turns, pause for a while; then turn 1/8 turn, then pause for a while ... and so on until it can be put into the lock pin. A quick press operation may result in damage to the bottom of the tensioner, resulting in unnecessary waste.
    Third, the compression process must not be hammered with a hammer. 3.4 engine "32-2" crankshaft teeth in the uniform distribution of 36 teeth structure, of which there are two teeth with a smooth structure, play the crankshaft position sensor CKP role. But due to improper beating spell damage caused by crankshaft teeth, will cause the crankshaft position sensor signal distortion, and ultimately affect the engine performance.
   Fourth, the balance bolt tightening torque has a clear requirement. Toyota engineers were unable to meet the required values ​​(294N · m) for some of the reasons since the tightening torque of the balance bolts was reduced due to the failure to start the pump or timing belt, the power drop and the engine noise. Some of the maintenance personnel The requirements of the tightening torque no known, just to tighten it, so as to plant a hidden danger.