What are the reasons and detailed steps for engine repair? This question seems to have been very popular, showing the importance of engine repair. Of course, the engine is equivalent to the human brain. Once a malfunction occurs, the corresponding equipment cannot be operated. There are many reasons for this malfunction. Today, let's talk about the car engine, see the reasons for the car engine repair and the detailed steps, I hope it will be helpful to everyone!

The first thing we have to consider is: why do engine overhauls?

1. Reasons for skills

1) Decreased power: ① Inability to start, climb and overtake; ② Black smoke or blue smoke from the exhaust pipe.

2) Oil pressure drop: lower than the original specification.

3) Cylinder pressure drop: 30% lower than the original specification.

4) The vacuum degree of the intake manifold decreases: it is lower than 57KPa at idle speed.

5) Add fuel and oil consumption.

6) Difficulty starting the hot car: the water temperature is 60-70℃, and the engine is difficult to start.

7) Significant abnormal noise: such as the sound of the piston knocking on the cylinder, the sound of large and small tiles, etc.

2. Non-skilled reasons: for example: accident reasons, economic reasons, car owner requirements, etc.

Secondly, we have to consider: how to do a good job in engine repair?

The overall process: receiving orders, checking → lifting and unloading the engine → cleaning the engine → dismantling, testing → repairing, accessories → installation, debugging → self-inspection, general inspection → beauty, delivery.

1. Take orders and view by order

1) Inquiry about the scenery: Ask the owner, driver or pick-up person of the scenery information about the engine overhaul in detail as much as possible; 2) Check the test drive: start the engine and check it for a test drive.

2. Lifting and unloading the engine

1) Disassemble the accessories: lines, pipelines, generators, compressors, etc.; 2) Disassemble the engine: use a hydraulic crane or a gantry crane to hoist the engine from the engine room.

3. Internal and external cleaning initiator

1) External cleaning: to clean the dust, sludge, etc. on the surface of the initiator; 2) Internal cleaning: to be carried out during disassembly (see step 4 for details).

4. Dismantling, testing and repairing

1) Dismantling: pay attention to the dismantling sequence, better than marking; 2) Inspection: while dismantling, inspecting, recording, and analyzing; 3) Fixed repair: determine which parts need to be replaced, which ones need outsourced processing, and which ones can be repaired by yourself . Write a written repair plan.

5. Accessories, outsourcing and repairs

1) Requisition for accessories: fill in the requisition form, and provide old parts as templates; 2) Outsourced processing: such as boring cylinder grinding shafts, inserting valve seat rings, grinding cylinder block planes, etc. ; 3) Self-repair: reaming, grinding valve, tapping thread, etc.

6. Installation and debugging

1) Receiving: Check the quality of repaired parts, outsourced parts, and purchased accessories. 2) Installation: install, inspect, and debug at the same time; 3) Hot grinding: 2 to 4 hours (conditional can be run-in by cold machine); 4) Hoisting: install the starter to the starter room, install the accessories, and carry out the corresponding debugging.

7. Self-inspection and general inspection

1) Self-inspection: For the completed engine, self-inspection should be carried out according to the inspection specifications for engine overhaul. If it fails to pass the inspection, it will be reworked until it is qualified; 2) General inspection: as long as the self-inspection is passed, the general inspection can be carried out, and the vehicle can be delivered only if the general inspection is passed.

8. Cosmetology and delivery: beauty and delivery of vehicles that have passed the general inspection.

In the end, I just want to think about how to do the inspection of the engine repair?

General inspection process: static inspection; dynamic inspection; delivery; unqualified; qualified; rework.

1. Static check

1) Check "Installation": tightening, piping, circuits, etc.; 2) Check "Add": fuel, oil, cooling water, etc.; 3) Check "Air Pressure": ① Cylinder pressure: conform to the original specifications, each cylinder The pressure difference is less than 3%~5% of the average value; ② Intake manifold vacuum degree: The vacuum degree behind the throttle valve at idle speed is 57~70KPa.

2. Dynamic inspection (this is the key point, everyone needs to pay attention)

1) Check the starting function: when the temperature of the gasoline engine is above 3 ℃, and the temperature of the diesel engine is above 5 ℃, it is required to start smoothly within 3 times (5 seconds each time).

2) Check the idle speed function: the speed conforms to the original specifications, and the work is stable, without trembling, without traveling, and without turning off the engine.

3) Abnormal sound check: Except for the slight valve foot sound and timing gear sound, no other abnormal sound is allowed.

4) Accelerated inspection: good transition, no stuffiness, no fire, no tempering, no trembling, no flameout.

5) "Temperature" check: 86℃ (80℃～90℃).

6) "Four leaks" check: no oil leakage, no water leakage, no air leakage, no electricity leakage.

7) Exhaust gas inspection: meet the national standard requirements (above National III) or international standard requirements (above Euro III).

Note: Those who pass the first and second steps will go directly to the "5" step, and those who fail to pass the inspection will go to the "3" step.

3. Rework: Return the unqualified products for rework.

4. Inspection: Inspection of reworked items.

5. Delivery: Those who pass the inspection can go through the delivery procedures (beauty, settlement, relevant instructions).

The above are the reasons and detailed steps for car engine repair. We can see that each repair step is very detailed. As long as we correspond to the repair steps according to the above failure reasons, I believe that everyone can easily solve all the failures of the car engine.