Operating temperature of turbocharger and exhaust manifold and other parts of the diesel engine is high. When they are operating, there is intense vibration. The fastening means of chemical coating and nylon locknut will fail on the condition of high temperature. The fastening means of double nut and thrust washers is slightly better than the previous two vertical solid way, but the installation is not very easy, and the anti-loosening effect is not very good.
        The special thread shape of 30° variable tooth type locknut can effectively overcome the above weaknesses. It is able to withstand strong vibrations at high temperatures when tightening well. After switching to 30° variable tooth type locknut on the part of oil pipe, exhaust, pipe, turbocharger of the diesel, it effectively solves the problem of nut loose at high temperature. At present, some well-known diesel engine manufacturer such as Weichai Power, have adopted the 30° variable tooth type locknuts in these areas, locking effect is very reliable.