Detecting and troubleshooting of engine cylinder head deformation

Deformation failure phenomenon of engine cylinder block and cylinder head

(1) The engine emits white smoke.

(2) When idling, open the water tank cover to see air bubbles in the water tank.

(3) The cylinder pressure is low.

Engine cylinder block, custom cylinder head deformation failure cause

(1) The cylinder body has residual stress during casting and machining. Due to insufficient aging treatment of the part, the internal stress is very large, and the internal stress is redistributed at high temperatures.

(2) The force generated by the reciprocating motion of the crank-link mechanism acts on the cylinder block, causing the cylinder to be pulled, pressed, bent, and twisted, and the plane of the cylinder block is warped and deformed.

(3) When tightening the cylinder head bolts, do not tighten them in the prescribed order, excessive or uneven torque, or remove the cylinder head at high temperature.

(4) The engine has been working under high-speed and high-load conditions for a long period of time, and insufficient lubrication, burning of the shaft, etc. caused deformation of the cylinder block and change of the center line of the bearing seat hole.

Diagnosis and inspection of engine cylinder block and cylinder head deformation

Inspection of cylinder block and cylinder head

Cylinder block and cylinder head technical standards and requirements

1. Cylinder block deformation: The maximum deformation of the upper plane is 0.05mm.

2. Cylinder head deformation: The maximum deformation of the lower plane surface is 0.05mm, the intake manifold side plane is 0.10mm, and the exhaust manifold side plane is 0.10mm.

Cylinder Head

Cylinder block inspection precautions

1. The upper plane of the cylinder block and the lower plane of the cylinder head cannot be placed directly on the workbench or on the ground.

2. When cleaning the upper plane of the cylinder block and the lower plane of the cylinder head, do not strike with a hammer to avoid new deformation or damage.

3. Wear protective goggles when blowing kerosene on the upper plane of the cylinder block and the lower plane of the cylinder head with compressed air.

4. The blade ruler should be handled gently to avoid deformation or damage due to impact with the measuring surface.

5. The ground of kerosene splashing knife should be cleaned in time to avoid personal injury caused by slippery ground.

Cylinder block detection operation steps

First, pretreatment

1. Clean the upper plane of the cylinder block and the lower plane of the cylinder head

(1) Use a wooden square pad to cushion the cylinder block and the cylinder head, so that the upper plane of the cylinder block and the lower plane of the cylinder head are upward.

(2) Use a shovel to remove the residual adhesion on the cylinder pads on the upper surface of the cylinder block and the lower surface of the casting cylinder head, and on the intake and exhaust interface planes on both sides of the cylinder head.

(3) Sand fine residual sand that cannot be removed by the blade.

(4) Put it in the cleaning basin, and clean the upper plane of the cylinder block, the lower plane of the cylinder head and the intake and exhaust interface planes on both sides of the cylinder head with kerosene.

(5) Clean the kerosene on the upper surface of the cylinder block and the lower surface of the cylinder head with compressed air.

2. Clean measuring tool

(1) Clean the blade edge with cotton yarn or rag.

(2) Clean the feeler with cotton yarn or rag

Second, the measure