ООО “Спец-автотехника-М”
English в русский

Damper and it’s role in operating equipment

Damper is a device for damping mechanical vibrations (damping), appearing in vehicles, devices, systems or buildings during their work process, or preventing oscillation.
What is the role of damper?
Damper pulley, better known as the crankshaft pulley, is a pulley installed on a front portion of a crankshaft. It rotates belt drive of the optional equipment, which includes generator, air conditioning compressor, power-steering pump, water pump, etc. 
Modern engines create significant torsional vibrations in a crankshaft.
Damper pulley has cushioning effect if loads on a crankshaft. The elastic part of the pulley absorbs vibrations, that appear due to the cyclic nature of the work of engine.
Last generation of the diesel engines operates on a low frequencies, that can significantly reduce the life of the optional equipment. To avoid this they use a pulley with a double insertion of the elastic element(photo 1).

Types of dampers
Engine pulley, working on technology “Stop-Start”
More advanced technically, withstand many consecutive engine starts. But standard versions of damper  are still used. For example: DPF359.09 => C3 1,6 Hdi (photo 2)
Double pulley-damper
Mounted on many diesel engines, technically the most difficult type.  Manufactured  from 7-8 metal parts and 2 rubber inserts. For example:  DPF359.03 (photo 3)
Single pulley-damper
Widely used on diesel and petrol engines. Consists of 3 parts: 2 metal (iron, steel, aluminium) and a rubber  element, that connects this 2 parts. For example: DPF358.24 (photo 4)
Monoblock pulley
It still finds areas of application, but it is losing popularity, especially with the appearance of technology “Stop-Start”. For example: DPF355.05 (photo 5).

Novelty on  aftermarket
Developed only 5 years ago, damper pulley showed strong sales growth thanks to:
- awareness of the need for periodic replacement:
- increase of vehicles, equipped by damper pulley (comparing to monoblock pulley):
- growing number of cars, where it is necessary to replace the crankshaft pulley due to increasing loads ( increasing the number of drive elements, the “Stop-Start” technology, downsizes engines) 
At the moment 95% of the sales are diesel engines.
Why change damper pulley?
Deterioration of the pulley may cause failure of a crankshaft.
Deterioration of the pulley may cause the noise and vibrations, uncomfortable for the driver and passengers.
Simplification and economy
Are you changing the kit of GRM-rollers? Then use the opportunity to replace the dumper pulley, thereby, reducing the time that your car spends off-road.
Why do the NTN-SNR  recommends also replacing the bolts?
During initial setting or replacement of damper bolt twists with high-torque tightening, and sometimes with the delta angle, depending on requirements of a car manufacturer.
        • Renault Laguna 1.9dCi: 2daN.m+115° => vendor code NTN-SNR DPF355.08
        • BMW 3 Series 318d: 10daN.m+150° => vendor code NTN-SNR DPF350.01
- bolt material is close to the elastic limit.
- according to the plan of design bolt deformed and lengthened.
- bolts must be replaced, especially if during the installation is used complete rotation through a certain angle (photo 6).

What are the risks in using old bolts?
- the failure of pulley or a bolt.
- breakdown of the bolt causes further damage of the belt and other elements of the additional equipment.
- NTN-SNR  strongly recommend replacement of bolts together with damper, especially if the is delta angles. That is why NTN-SNR  offers a full range of dampers, including bolts, required to satisfy this need.
Range of NTN-SNR  production
List of products has 180 vendor codes. It is one of the widest ranges on a  market, which includes:
- more than 40 individual products:
- 33 sets of dampers with bolts and collars – double benefit for the owner of service station, providing:
1. repair according to the recommendations of a manufacturer:
2. mechanic saves time, as all needed details comes under one vendor code and in one box.
Staying true to the politics in the field of quality of production and positioning itself as a premium supplier, NTN-SNR  offers bolts and collars of original quality.
Why should we choose the range of dampers NTN-SNR ?
There is a number of reasons:
- the range includes the biggest list of details , supplied on a conveyor:
- the quality of production, proposed by NTN-SNR;
- products are tested and checked by the Depatment of quality. NTN-SNR focuses specially on a concept “original”. For the company it is a guarantee of the security of clients!
- quality of expertise of one supplier(simplification of legal liability);
- the process of purchase is simplified because of cooperation with one contact on the entire range of engines;
- NTN-SNR is a manufacturer of the original equipment for VAG, Mercedes, Toyota, Hyundai…
NTN-SNR also cares about optimization of keeping it’s production , for which was developed special packing with separate department for bolts. And for the optimization of space for keeping, the two different size boxes were created(photo 7).
Spare parts must be stored in a special packaging, protected from external damage and moisture. You should avoid the contact with oil, acid and alkali (because of the risk of rubber damage).
Inspection and replacement!
Due to heavy loads dumper pulley is subjected to deterioration and, consequently, needs regular check and preventive replacement  in case of unsatisfactory condition. It is important for driver to know the signs, by which he can determine fault of the damper.
These signs include:
- perception of unusual vibrations in the car interior;
- hearing the whistling of the drive belt;
- unusual noise or knocking.
Dynamic inspection of pulley – it’s easy!
I. When the engine is turned on, draw a line from the edge to the centre of damper.
II. Start the engine and turn on different electric equipment (conditioner, power steering, turning the steering wheel, etc.)
III. Stop the engine. Check the tags on a pulley – they should remain on their places and match (there should not be the turn of a central part of the pulley relative to the outer). Otherwise the damper should be replaced, as the rubber inserts do not fulfill their role anymore.
Visual check
Every 60000 KM car mileage, you should make visual check on such features:
- cracks in a rubber;
- rubber fusing because of oil leak, for example;
- rubber deformation;
- cracks on a hub or in the area of twist;
- separating of different parts of the damper;
- cracks on a drive belt.
Replacement of the damper
During the replacement of damper it is necessary to follow the instruction of manufacturer, that describes such sequencing for the repairers:
- replace damper at the same time with GRM kit (on the average between 90000 and 120000 km);
- use appropriate tools ( the hammer, wrench, Hazet kit for mounting);
- replace the bolts and collars;
- stick to the torque and the delta angles, recommended by the manufacturer;
- always replace the belt of the optional equipment;
- check the other parts of the system ( generator, tensioner pulley);
- never start the engine without the drive belt!
Not just a pulley!
The NTN-SNR company offers wide range of products for the engine OEM quality, to provide clients the best production:
- rollers of additional equipment and overtaking generator pulley;
- belt of the additional equipment;
- repair kits of the rollers of the additional equipment;
- full range of the GRM rollers.
Copies improper quality
Be careful! Some manufacturers offer “ indestructible” damper pulleys, but this quality is fatal for the crankshafts and for the engine itself. Allegedly different metal parts  are actually organic whole. And the rubber part , that imitates existence of the elastic element, actually is a ring , inserted into the groove of solid metal pulley.
This type of detail noway matches the requirements of the manufacturers.
Vibrations without absorbing and, as a rule, bigger weight, comparing to the original detail – put under threat the strength of the details of the engine, particularly the crankshaft, that can lead to the serious breakdown.