When you need a cylinder head cylinder head grinding
Experts recommend inspecting and grinding the cylinder head during any complex work on engine components that involve the removal of the block. Direct indications for the process are.
- Abnormality in the geometry of the part caused by overheating.
- After welding work. If there were defects in the head that were repaired by welding, grinding is a compulsory action after their completion.
REFERENCE. Grinding is also carried out in order to increase the power of the engine during its fine tuning. Decreasing the head height allows an increase in compression ratio.
Deformation of the cylinder-head cylinder head leads to a loose fit of the gasket, and this in turn causes problems in the engine operation:
If these problems occur, unscheduled cylinder-head grinding is required.
Which engines can be sharpened and which cannot be?
As you know, the cylinder block can be made of cast iron or aluminum. The first variant, despite some disadvantages, such as high weight and low heat dissipation, has good strength and is perfectly shaped. By contrast, the aluminum block is much lighter and dissipates heat more efficiently.
However, its cylinder walls are coated with a special wear-resistant compound, so turning them is not recommended. This procedure simply removes the coating from the walls, and as a result the cylinders lose their strength and do not last long.
How the cylinder head is ground
Let’s start with the fact that qualified operations with the cylinder head and cylinder grinding at home is not recommended, although it is possible and there are several ways. Now let’s move on to the procedure itself, taking into account how it should be performed correctly. First of all, you need to carry out a check the plane of the cylinder head. This is done with a long steel ruler, and feelers (you can use feelers to adjust the thermal clearance of the valves). It is important that the ruler be flat, of uniform thickness, without bends or defects. The specified ruler should be applied to the bottom plane along the diagonals, and then a suitable feeler gauge is inserted into the gaps that are formed between the plane of the head and the applied ruler. These actions are performed one by one.
Next. If defects are found, then the next step is to check the head for cracks. In the garage usually use a paint or paint similar properties, which coated the body previously washed and cleaned from dirt cylinder head. Then the dye is removed from the surface, after which the remains of the dye in the cracks identify problem areas. The method is simple enough, but microcracks or internal housing damage cannot be detected with paint. For a more accurate diagnosis of the tightness of the body and to check for cracking of the internal surfaces, it is necessary to contact experts or have the right equipment on hand. The cylinder head must be heated, after which it is placed in a special water bath. Without going into detail, microcracks appear due to air bubbles, which escape as a result of pressurized air in the cylinder head housing. The cylinder head crack (if any) should then be repaired, after which the cylinder head can be ground.
During milling, the most important parameter is the allowable thickness of the grind. In simpler terms, you need to know how much metal can be removed from the surface of a particular cylinder head. Information on the depth to which you can grind the cylinder head, should be contained in the technical literature, repair manuals and additional sources with respect to the specific type and model of the engine. The engine manufacturer must be sure to specify this parameter for the repair, after which the unit will operate normally. If the defects of the plane is too serious, that is, deep milling to eliminate them may need to remove all the allowable margin and exceed the manufacturer’s recommended value, then in this case may need to make a replacement of the cylinder head.
What needs to be prepared
First of all, before you start grinding the cylinder head, you need to prepare the tools. The most paramount thing you will need. a set of screws of different caliber and a ruler with a template.
In general, the second you will need only in order to estimate what exactly should be the head. The entire process is basically done by eye only.
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This does not include cases where the process is carried out on a cylinder head grinding machine, there are precise instructions.
It is obligatory to check the cylinder head before sanding. You should pay attention not only to dents and changes in the body.
Also take into account scratches and cracks, which an ordinary paint will help to detect.
We take a bright paint, apply it to the surface and literally after a couple of minutes erase.
Cracks and scratches will leave paint. If you already can not do the procedure yourself, it is better to find out in advance how much it costs to grind the cylinder head.
Preparation for the process
The first step in performing the work is to assess the condition of the cylinder head. Defective inspection of the fitting surface is carried out, having set the block on a perfectly flat surface with a steel ruler and a set of feeler gauges. Without defects, even thickness ruler applied to the bottom plane along the diagonals with the edge of the ruler. If a gap is visible between it and the surface of the block, a feeler gauge is inserted into it.
Allowable and not affecting the operation of the cylinders admit gaps up to 0.05 mm. If the gap is more than 0.1 mm, grinding is necessary. If there are significant gaps, the cylinder block should be replaced. Flat grinding is used only if the height of the head after the process will not be less than 135.60 mm.
IMPORTANT. If there is a blowout of the gasket, the surface deformation will be located in or near that spot.
After a head deformation is detected, inspect the cylinders of the BC for cracks. Parts with large cracks are not worth grinding, because it still will not work properly.
If no major defects are found, the block is inspected for the presence of micro-cracks. In conditions of service stations it is done with the help of special equipment. In the garage, the method of checking. painting the block, followed by cleaning after 5-6 minutes. After the paint is rubbed off the surface, it becomes blocked in the cracks and the cracks are clearly visible. But only external micro cracks can be detected in this way. In this case, the internal ones remain unnoticed. Micro cracks must be removed before the grinding process.
When the cylinder head to grind
Any defects that affect the tightness and sealing of the cylinder head to the engine block itself leads to malfunctions and / or failures in the engine. The most common reason for which the cylinder head must be ground as part of an engine overhaul is engine overheating. A common problem is also considered to be a violation of the head tightening rules during engine assembly, after which the cylinder-head housing is deformed.
S330R Surface grinder for cylinder heads
Most often an unscheduled cylinder-head inspection is performed when there are problems with the cylinder-head gasket. The specified gasket can burn through, resulting in a breakthrough of gases from the combustion chamber, through it can leak engine oil or antifreeze. Before replacing it is necessary to determine exactly why the cylinder-head gasket is pierced or punctured.
Such repair is shown to any unit, regardless of what work is carried out (replacement of the camshaft, gaskets or other). If otherwise, after removing the head and disassembly, it is worth paying increased attention to the condition of the surface in parallel with other operations.
How the head block is grinded
Let’s start with the fact that qualified operations with the cylinder head and cylinder grinding at home is not recommended, although it is possible and there are several ways. Now let’s move on to the procedure itself, taking into account how it should be performed correctly. The first step is to inspect the cylinder-head gasket surface. This is done with a long steel ruler and feeler gauges (you can use feelers to adjust the valve clearance). The important condition is that the ruler must be even, uniform in thickness, without bends and defects. The specified ruler should be applied to the lower plane along the diagonals, and then a suitable feeler gauge is inserted into the gaps that are formed between the plane of the head and the applied ruler. These actions are performed one by one.
Let’s move on. If the defects are found, then the next step is to check the head for cracks. In the garage usually use paint or paints similar in properties, which coated the body previously washed and cleaned from dirt cylinder head. Then the paint is removed from the surface, and then the problem areas are identified by the remains of the paint, trapped in the cracks. The method is simple enough, but microcracks or internal damages of the body with paint can not be defined. For a more accurate diagnosis of the tightness of the housing and to check for cracks on the inner surfaces, it is necessary to consult a specialist or have the appropriate equipment at hand. The cylinder head needs to be heated and then the cylinder head is placed in a special water bath. Without going into detail, microcracks appear due to air bubbles that escape as a result of pressurized air flowing into the cylinder head housing. Then the cylinder head crack (if any) should be repaired, after which the cylinder head can be ground.
Grinding the cylinder head in the garage
Good day, dear motorists! It’s probably no secret to you that the cylinder head is a very specific part of a car engine. All the systems and parts of the cylinder head are very closely interconnected, and any malfunction of the parts is usually the result of a more significant defect in the cylinder head.
For example, if you find that the cylinder-head gasket is out of order and leaking oil, then in addition to directly replace the cylinder-head gasket, it is highly recommended to find the cause of why the gasket occurred.
And the reason can be banally simple. even a slight engine overheating or accidental exposure to water can cause a deformation of the cylinder-head cylinder head and as a consequence, the burning of the gasket.
Simply speaking, it is necessary to carry out a complete inspection of the condition of the cylinder head. And it is likely that the cause of the gasket breakdown was a violation of the interface between the cylinder head and the cylinder block. In this case, you need, without reservation, milling or otherwise, the grinding of the cylinder head.
When you need a cylinder head grinding
Let’s see, for what you need to grind the cylinder head, and grinding cylinder block, too. Grinding of the cylinder head is carried out to bring to necessary parameters of the cylinder head surface mating with the surface of the block.
Cylinder head cylinder head grinding is carried out in two cases. The first, which is not particularly relevant to the average driver is an engine tuning. To increase the compression ratio, reduce the height of the cylinder head. But, that was in the period when we had no idea about the availability of good quality fuel. That is, this option can be left for the most fanatical adherents of changing engine parameters.
The second option, when it is mandatory to perform grinding of the engine head is the repair of the cylinder head. Repair in any form, whether you needed to change the gasket or you decided to replace or repair the camshaft. Don’t limit yourself to the exact repair operation for which you disassembled the cylinder head. After all, you have already removed it, take a little time, so that a little later you do not have to start the repair of the cylinder head again.
Preparing the cylinder head for grinding
You can check the flatness of the head with your own hands, using a metal ruler and a set of feeler gauges. The ruler is applied in the lower plane diagonally, and pick up the dipstick, which enters the gap between the ruler and the plane of the head. The method is far from exact values, but a general idea of the deformation of the mating plane it gives.
The most interesting thing is that near those cylinders where the gasket is burned out and the pistons with soot, you will see the greatest deformation of the head plane.
On top of that. According to the rules, grinding the head of the block is carried out only after you are fully convinced that the body of the cylinder head has no cracks. You can try to search for these cracks on your own, for example, with a dyeing agent.
Paint is applied to a thoroughly cleaned head surface, removed after 5 minutes and you can see the cracks. The imperfection of this method is that you are unlikely to see microcracks, or those cracks that went inside the block.
You have to use special equipment. Inspection of the internal cavities of the cylinder head for tightness is carried out in a special device, where the head housing is heated, and the cracks show themselves with the help of pressure and air bubbles in the water bath, where the head of the block is located. And only after the elimination of detected cracks in the block, you can proceed to grinding the engine head.
Grinding the cylinder head
Grinding the head you are unlikely to succeed with your own hands, as it is performed on a special milling and grinding machine. The technology should not interest you, but some subtleties you should know in order to apply them later when assembling the cylinder head.
Grinding thickness. The manufacturer in the manual to your engine model, should specify the maximum (repair) depth of grinding of a plane at which it guarantees normal operation of the engine.
It is desirable that you specify from the master, to what depth will be milling, not forgetting to voice the allowable figures of the manufacturer. This is to find the right gasket of the right thickness. And, if it is necessary to shorten the valves, you need to know how much.
It is not worth experimenting with the engine. If the maximum reserve voiced by the manufacturer is exceeded during grinding, the cylinder head will have to be replaced.
The grinding procedure does not take much time, and after getting your hands checked for leaks and polished cylinder head, you can safely install it in place.
Grinding the cylinder head
Car engine breakdowns are the most common problem for drivers. And the most common cause of failure is a problem with the cylinder block.
The cylinder head can lose its shape during operation, it simply warps, resulting in very serious damage.
When these situations arise, car owners wonder how to solve the problem. It’s actually much simpler than it seems.
Grinding the cylinder head is used to return it to its normal shape. In this material we will talk about the peculiarities of such an operation.