Select your language
NTN-SNR Auto Aftermarket home >  Products >  Accessory >  Damper Pulleys
Print

Damper Pulleys

Range:

 

 damper_coupé 107 references, most are original or, of original quality.
Damper Pulleys have the following numbering system: DPF350.00
DPF = Damper /  Pulley Filter
350 = as with standard Guide Rollers, it refers to the main vehicle brand concerned
.00 = an incremental number for the range extensions.



 

Where do you find Damper Pulleys on an engine?

The damper pulley is fixed on the end of the engine crankshaft near to the timing and accessory pulleys.

 damper_emplacement


1. ITS PURPOSE AND FUNCTION 

The damper pulley is part of the belt drive system, which operates accessories such as, air-conditioning, power-assisted steering, alternator, etc. Its function is to dampen out the vibrations in the crankshaft in the same way as a balancing shaft. The damper pulley is technically complex, and cancels out the torsional vibrations in the engine crankshaft. The damper pulley is subject to wear and requires changing periodically. If defective, it will fail to dampen the forces generated by the modern high torque engine. 


2. TECHNICAL DESCRIPTON



 

damper_entier A damper pulley has 3 basic component parts:
- An inner metal hub, of steel, cast iron or aluminium, which is fixed to the crankshaft.
- An outer grooved rim, where the belt runs
- A central ring of rubber between the two metal parts.

The pulley filter in some cases consists of up to 7 metal parts with 2 rubber inserts. This being the case for the top selling reference - OE PSA: 0515V6.

The metal parts and choice of rubber are determined by the different stiffness characteristics, specifically developed, for each engine. They must meet the exact requirements and frequencies of each application. We can say that the damper pulley is in tune with the crankshaft.

The damper pulleys have an average diameter about 150mm, a weight range from 1 to 8 kg,  the number of grooves is from 3 to 7, and some dampers are “double” controlling two accessory belts.


3. THE AFTERMARKET

Replacement recommendations 

Manufacturers do not specify when to change a damper pulley.
However, so that the problems associated with failure can be avoided, replacement is recommended when engine timing components are changed.
In addition, a defective damper can be identified by noise and vibrations felt inside the vehicle.


4. CAUSES OF FAILURES

The major cause of returned damper pulleys is due to the noise coming from  the front of the engine near to the timing and accessory systems. However the damper pulley is like a microphone and picks up various noises emitted by the engine, which can put it out of synch after controlling the vibrations.

The failure of a damper pulley can arise from contamination of the rubber, for example by oil. This causes the rubber to swell up causing a loss of the mechanical properties.

Additionally a foreign body could damage the damper pulley and impair its function.

Seizure of a component part of the “accessory chain” (air conditioning, power steering, alternator free wheel pulley…) could equally damage the damper pulley by overheating the belt. The heat is conducted through damper pulley and the increase in temperature affects the mechanical properties of the rubber.


5. RISKS FROM FAULTY COPIES

 

damper_origine damper_contrefacon

Some copies are of very poor quality, mostly due to the low quality of rubber used and can therefore, have a considerably reduced lifespan.

 OEM Part

 Copycat Part

 



 

Some manufacturers have copied damper pulleys using a simplified technique, resulting in lower manufacturing costs, but an inability to cope with the primary function of a damper pulley. In other words, the rubber insert that joins the hub to the outer rim, was replaced by a groove, in which an O ring was fitted. With this arrangement, the damper pulley is effectively a solid pulley, which does not meet the properties of the original product. This type of modification usually leads to cracks, which continue until the crankshaft ruptures.

We also find products with much higher weights than the original assembly, or unbalanced parts, which in the short or long term will obviously have consequences on the lifespan of the engine.


6. REMOVAL / FITTING OF A PULLEY DAMPER (source: Doc.  Metaldyne)

Usable temperature range:

140°C maximum for intermittent use/120°C continuous duty
-40°C au démarrage

Assembly:

- Avoid any impact to the drive edge face of the pulley, where contact with the belt or timing gear is made, care should be taken with the adjuster bolts and accessory belts, to prevent over tightening, belt wear and oil seal leakage
- Do not exceed the maximum tightening torque of the locating screw (a risk of fracture or distortion).


Removal:
- Do not use an extractor, screwdriver, or other means putting load on the ring.
- Do not heat the part to remove it: no burner, blowtorch, or any other source of heat (a risk of deterioration to the rubber, distortion of the assembly dimensions or flatness…)
- Do not use any new part which suffers an impact (e.g. fallen parts) since it can no longer be functional
- Do not handle the parts without clean dry gloves, in order to avoid the risks of oxidation


Storage :
Store the parts in specific containers and packing, to protect from contamination and moisture.


Avoid any contact with oil, solvents, acid, or varnish (a risk of deterioration to the rubber).