Diagnosing the condition of the cylinder-piston group without fully disassembling the engine is the holy grail of any mechanic and owner of an automobile. Imagine that you can look inside a working unit without removing the cylinder head or spending hours dismantling attachments. endoscopyThe use of specialized optical techniques allows the detection of critical damage in the early stages, when symptoms are not yet obvious and economic damage is minimal.
Today, a wide range of devices is on the market: from budget USB cameras to professional videoscopes with IR illumination. Cylinder inspection camera It has become an integral tool in the arsenal of service centers dealing with the repair of outboard motors, automotive engines and industrial equipment, and in this article we will discuss in detail how to choose the right equipment, what defects can be detected and how to interpret the resulting image to make the right decision about repair.
Before you start buying expensive equipment, it is important to understand the physical principle of such devices: an optical system must withstand an aggressive environment, have sufficient depth of field and, critically, the correct geometry of the probe to access candle or nozzle wells. Visual control through the screen allows you to document the state of the parts, creating an archive that will be useful for further operation or sale of equipment.
The principle of operation and Construction of the technical endoscope
The technical endoscope, or boroscope, is a flexible or rigid probe, at the end of which is a miniature camera with a backlight system. LEDs located around the lens illuminate the dark inside of the cylinder, allowing the camera to transmit a clear image to the monitor. Modern models often have a rotary mechanism, which allows you to change the angle of view. lens It's not like you're taking the probe out of the hole, and it's especially useful when you look at the side walls of the casing.
The key element is the probe itself, which has a diameter smaller than the diameter of the candle hole, and the envelope material is resistant to oil, gasoline and high temperatures, and inside the probe passes a fiber optic light guide or electrical conductors that transmit the signal. Tube flexibility should be optimal: too soft will get stuck, and hard can damage the walls of the cylinder with careless introduction.
The resolution of the matrix directly affects the quality of diagnosis. To detect microcracks or the initial stages of honing requires high resolution. Budget models often sin with a soap image in insufficient light, which can lead to false conclusions. Professional systems have the function of digital zoom without loss of quality, allowing you to consider parts in size of a fraction of a millimeter.
What is the difference between a boroscope and a videoscope?
A boroscope is the generic name for a visual device for hard-to-reach areas. A videoscope is a more advanced version of a boroscope, equipped with a video camera at the end of the probe and a screen for displaying images in real time. Videoscopes allow recording video and photos, have more complex optics and are often more expensive than simple USB boroscopes.
Criteria for the selection of equipment for the diagnosis of ICE
The right camera depends on the type of engine you plan to work with. For car engines and powerful boat units, the length of the probe and its diameter are important. The standard diameter of the probe is from 4 to 8 mm. Too thin probe (less than 3.5 mm) may not have enough rigidity to pass through the bends of the intake manifold if the inspection is carried out through the intake windows.
The next important parameter is connectivity and functionality. Wired models are more reliable and not afraid of interference, but limit the mobility of the wizard. Wireless models that connect to a smartphone via Wi-Fi are more convenient, but require a stable battery charge. videotape and photofixation with reference coordinates or time stamps.
- 🔍 Camera resolution: A minimum of 720p, preferably 1080p for detailed scratch analysis.
- 💡 Adjustment of the illumination: The ability to change the brightness of the LEDs to avoid glare on oily soda.
- 🛡️ IP protection: The protection class is not lower than IP67, as the cylinders always contain fuel vapors and oil.
- 📏 Length of probe: Optimal 1-2 meters for free access to any cylinders of inline and V-shaped engines.
You don't need to skimp on optics. Cheap plastic lenses quickly get cloudy from contact with aggressive chemistry or (high temperature) if the engine is heated. Glass optics and metal camera body are signs of a quality device. Also note the presence of interchangeable nozzles that can protect the lens from oil droplets or antifreeze.
Preparation of the engine for video diagnostics
The quality of the inspection depends on the preparation of the unit. A dirty, coked engine will give a distorted picture. Before inserting the camera, you need to turn the spark plugs (or injectors, depending on the access method). If the engine was recently running, let it cool so as not to damage the thermally sensitive elements of the endoscope, although most of them are designed for short-term contact with hot air.
It is important to keep the candle well clean. Dust and debris that enter the cylinder along with the probe can become abrasive on the first start. Blow the well with compressed air before removing the candle. If there is a lot of carbon in the cylinder, initial inspection can be difficult, and it will require preliminary decoking or gasping to "revive" the picture.
⚠️ Warning: Never enter the camera into the cylinder if the piston is in the top dead point (BMT) and you plan to turn the crankshaft. this is guaranteed to crush the camera and cause serious damage to the HBC.
For a better view of the cylinder walls, it is advisable to lower the piston to the lower dead point (LMT), which will open the maximum area of the side surface of the sleeve. Yamaha or MercuryAccess can be limited by the exhaust muffler design and variable geometry probes are required.
☑️ Preparation for endoscopy
Typical defects detected by the camera
The main purpose of the camera is to detect mechanical damage, and the most common defect is to detect mechanical damage. bully They look like vertical deep scratches, they indicate a violation of lubrication, overheating or destruction of piston rings, and even small bullies in the top of the cylinder (in the area of the relaying of the rings) are alarming.
The second important aspect is the condition of the piston and the rings, and the camera allows you to see the stain on the bottom of the piston, which may indicate that oil has entered the combustion chamber or that poor-quality fuel has been used. ringingCracks on the piston, especially around the tubs or on the skirt, are often only visible through the endoscope.
Particular attention should be paid to valves. Through the candle hole, you can often see the plates of valves; Gas, burnout or cracks on the valves are a common cause of loss of compression. In two-stroke outboard motors, the condition of windows in the sleeve and piston rings is critical, which, when worn, can break and destroy the cylinder.
| Type of defect | Visual signs | Probable cause | Elimination method |
|---|---|---|---|
| Bullies. | Vertical deep furrows | Oil starvation, overheating | Block waste, pistons replacement |
| nagar | Black loose or hard layer | Rich mixture, oil in cylinders | Excavating, replacing oil caps |
| HBC cracks | Thin lines, often at the valve seat | Overheating, hydrostroke | Replacement or repair of the block head |
| Corrosion | Rusty spots, shells | Water intake (relevant for boats) | Honing (if depth) or replacement |
When you look at a two-stroke engine, look at the color of the piston. Brown or chocolate plaque is a sign of the mixture working properly. White plaque or melting indicates poor mixture and overheating, which requires tuning the carburetor.
Interpretation of the image: nuances and errors
Getting an image is only half the battle. The main thing is to read it correctly. Often beginners confuse the reflections of light from the khon (notches on the cylinder walls) with scratches. Hong If the grid has disappeared at the top of the cylinder, it indicates the resource development, and glossy spots on the walls are a sign that the rings are not fitting tightly.
It's important to consider the angle of light. The glare from the oil film can hide real defects. Change the brightness of the backlight and the angle of the camera. If you see rainbow shimmers on the walls, this could be a sign of antifreeze hitting the cylinders through a burnt gasket of the GBC — the so-called "emulsion."
When diagnosing outboard motors, it's important to remember the specifics of their work. Two-stroke engines are mixed with oil, so light oil mist and rainbow films at the bottom of the crankcase (if visible through the exhaust windows) are normal. However, the presence of large drops of water or rust at the bottom of the crankcase is a critical signal of depressurization of the crankshaft.
⚠️ Attention: Don't confuse the design of aluminum casting with cracks. Factory lithic traces or wall roughness are often mistaken for damage. Compare the picture in all cylinders - the defect is usually localized, and the casting is the same everywhere.
Specificity of diagnostics of outboard motors
Outboard Motors, especially outboard motors, have their own diagnostic features. Access to cylinders is often hampered by housings and cooling systems. In two-stroke engines, inspection is carried out mainly through the exhaust windows at the bottom of the cylinder or through candle holes, if the design allows. piston-ring and the graduation windows.
Corrosion is a scourge of water technology. The camera helps to identify the stages of corrosion of aluminum alloys that have not yet manifested themselves as loss of compression. The white coating on the walls of the cylinder is the oxidation of aluminum. If it is not removed and preserved in time, the engine can "eat" the piston in one season of idleness.
For four-stroke outboard motors, the procedure is similar to that of a car, but be careful with the length of the probe. In compact cylinder blocks of marine engines, access may be limited. The use of a rotary-engine camera becomes not a whim, but a necessity for examining the space under the valves.
For outboard motors, the camera's tightness and resistance to salt water are critical. After diagnosis, be sure to wipe the probe with fresh water and lubricate it with silicone so that the salt does not erode the body.
Frequently Asked Questions (FAQ)
Can I use a regular USB endoscope for professional repairs?
For amateur diagnostics or quick engine checks, yes, that's acceptable. But for daily professional service work, it's better to invest in a dedicated videoscope, which has a more robust probe, better optics, oil and gasoline protection, and a recording function, which is important for reporting to the customer.
Do I need to remove the cylinder head for a high-quality diagnosis?
90% of the time, it is not necessary. Modern optics allow you to view up to 80-90% of the surface of the cylinder, the bottom of the piston and valves through the candle hole. Removal of the HBC is required only if you want to assess the state of the combustion chamber throughout the area or if access through the candle hole is structurally impossible.
What if the camera gets stuck inside the cylinder?
The fogging is due to the temperature difference between the cold probe and the warmed engine, or to the fuel vapor. Let the camera lie in the cylinder (not including the recording if you fear overheating, although you can briefly) or remove and wipe. Some craftsmen preheat the probe with a hairdryer. There are also antiphog sprays for processing the lens.
Is it harmful to put a camera in the cylinder often?
With careful use and keeping the diameter of the probe is not. The risk is if the probe has burrs or if you aggressively move it by scratching the walls. Always lubricate the probe with pure engine oil before insertion, this will make it easier to slide and protect the cylinder mirror from microscopic damage.