TILT CONTROL :

To check the curvature, the cover surface should be thoroughly cleaned, if necessary, with a fine sandpaper. must be cleaned and polished. In the control, a specially made control gauge and a sheet feeler are used. For this, the cylinder head is placed on a work table with the contact surface facing up. The surface is wiped with a clean cloth. The lining is made on the surface diagonally diagonally (cornering) and in each position, the feeler sheets cover from small to large. With , specifies the thickness of the blade that is not too tight. The curvature of the covers is usually in the middle, which should be carefully examined and checked.

THREAD AND CORROSION : As a result of long working and irregular tightening, the curved parts of the cover gasket are on the contact surface of the cover and block. If the threads are enough to be felt by the nail, the cover should be grinded. Otherwise, the cover installed without grinding will not be able to press the gasket enough, causing water and compression leakage and burning of the gasket.

QUESTIONS

1. Malfunctions and malfunctions What are the reasons?

2. When this part fails How does it affect engine running?

3. Control and How to measure, show with table and figure.

4. According to the measurement result How to decide to renew it?

5. How is the renewal process? done?

6. Chip to be removed from the part Calculate the amount.

7. on which machine is the process done?

ANSWERS

1. There are cracks, curvature, grooves and corrosion on the cylinder heads.

Crack is usually is caused by unbalanced tightening, excessive and irregular heat, insufficient cooling, irregular combustion, freezing of the water in the engine, placing too much cold water in the hot engine or the formation of too hot areas.

It is caused by the formation of different internal tensions due to reasons such as deformation of the cylinder heads, high temperature, insufficient cooling, and incorrect tightening.

2. When any of them occurs; water in oil, oil in water, loss of water in the engine, compression leakage, irregular idling and misfire are seen.

3. Cylinder head inclination control is done with gauge and feeler gauge.

Crack control on the cylinder head is done by various methods;

When the cylinder head is removed, the carbon on the cover is visually inspected before cleaning.

If there is a crack, will show itself as a thin line between carbon deposits.

Invisible cracks are found with the help of powder scraping

4. According to the measurement result, if the curvature is more than 0.10mm, the cylinder head is grinded.

Grinding steps are 0.25mm ‘

In grinding 0.50mm because the combustion chamber will shrink, thick or double gasket is used to prevent malfunctions.

5. According to the measured values ​​ for flat surface grinding machines chip is removed.

Grinding steps (0.25-0.50-0.75 .....) continues.

As a result of grinding is thicker for grinding operations after 0.50mm cylinder head gasket is used.

6. Standard six height: Standard height - Grinding step

Chip amount: Standard height - Amount of curvature - Substandard height

7. Cylinder head is renewed on flat surface grinding machines.

VALVE RENEW

QUESTIONS

1. What are the malfunctions and their causes?

2. When this part fails, how will it affect the operation of the engine?

3. How to control and measure the part, show it with table and figure.

4. How to decide to renew it according to the measurement result?

5. How to renew?

6. Calculate the amount of sawdust to be removed from the part.

7. On which machine will this part be renewed?

ANSWERS

1. Valve assembly It should always be repaired when the ring is replaced on the engine or the engine is undergoing general repair.

Malfunctions: Carbon deposits in the valves cause the cylinder blocks to crash by keeping the pressure in the combustion chamber higher than normal. At the same time, unburned carbon deposits gum on the valve stems, causing them to seize on the guides.

Exhaust valves: These are affected by distortion, burning, pitting and eccentric wear.

Intake valves: The intake valve is connected to the exhaust valve.the work is lighter. Burns and pitting depths that may prevent the suction valve from fully fitting into its seat cause the exhaust gases to pass through here and cause the formation of hard carbon deposits in the seat. The same can be caused by the weakness of the valve spring, the less than the valve clearance, the distortion of the valve stem and its eccentricity. Distortion is mainly caused by overheating of the part of the valve stem near the head. Eccentric wear of the seat is the result of the operation of a non-axial valve head with the valve stem and guide in this seat.

Excessive space between the valve stem and its guide causes oil to be sucked into the combustion chamber from here, causing the engine to spend too much oil, carbon formation and the mixture to be dirty.

Axis impermanence: Axiality in valves occurs as a result of wear, skew and skew. Abrasion caused by improper and insufficient lubrication end creates bell-shaped surfaces on one side. Such valves do not work axially.

2. Oil consumption increases in the engine. Especially in overhead valve engines, excess oil leaks into the combustion chamber between the worn valve stem and guides.

The exhaust is smoky; In engines that burn oil, the exhaust produces blue smoke.

Decrease in engine power; As the leakage increases in faulty valves, power and efficiency decrease is seen in the engine.

Noisy engine running; The valve arrangement works louder than normal due to wear and distortion.

Low idle running; Leaking leaking valves will prevent equal power from each cylinder, causing unstable cylinder operation.

Backfire in intake manifold; Leaking, leaking, or stuck intake valve causes ignition to pass to the intake manifold.

Blast combustion in silencer; A leaking, leaking or cramped exhaust valve causes the combustion to continue explosively in the muffler.

Engine running at low compression; Stuck, burnt, leaking or leaking valves will cause compression leakage.

3. The head, stem and tip parts of the cleaned valves are checked visually, with measuring and control instruments, and it is determined whether they can be used again. Some of the malfunctions in the valves are not visible. These can only be determined by measuring and control instruments.

4. Valve stem Determine the amount of abrasion, ovality and taper in the stem by measuring it with a micrometer from different parts (working sections).enir. If the stem is oval or the difference between the stems is greater than 0.05 mm and the excess is greater than 0.05 mm, the valve should be replaced.

If the upper edge wall thickness of the valve head is reduced by half or less than 0.8 mm compared to the new one, that valve should not be used. Valves with bent stem or head that cannot be corrected should be replaced.

The valve stem is connected to a lathe and the curvature is checked from the beginning with a dial gauge. If the runout is more than 0.02 mm, that valve should not be used.

At the end of the controls, the seating surfaces of the valves that can be used again, the stem face surface and the edge chamfer are grinded to make them work.

5. There are special machines for precise grinding of the valve surface. These benches essentially have a connection mechanism and other details that rotate the valve at the required angle with respect to the stone and with the motor. Stone valves grind the face properly and eliminate all kinds of burns and tingles. We can make a mirror shine with a well-sharpened stone.

6. In an engine whose guide cannot be removed, the valve guide is ground to a larger diameter and a large standard valve is used. If the type is changed, guide and valves are changed.

7. The bench used for changing the valves is the Valve Grinding Machine.

Alıntıdır.



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