Our Recent News

What are Motor Mounts?

The motor mount, a component made of rubber, metal or composite material, is the connecting part that is fixed between the frame and the engine. It has only two core tasks:

1. Fixed engine position – prevents the engine from shifting when accelerating or over bumps;
2. Absorbs Vibration and Noise – Absorbs up to 80% of the vibration generated when the engine is running.

If an engine that rotates 3,000 times per minute is hardwired directly to the chassis, the interior of the car will vibrate terribly. And the rubber or hydraulic components in the mount will absorb more than 80 percent of the high-frequency vibrations. More critically, it protects the alignment of the transmission driveshaft – and aging mounts can cause a 5-10% drop in power transfer efficiency.

More fatally, mounts displacement of more than 3 millimeters can throw the driveshaft angle out of whack.2021 The NHTSA investigated a batch of transmission failure complaints and ultimately found that 37 percent of the cases stemmed from deteriorated or broken engine mounts that had undergone significant displacement.

Classification of Motor Mounts

Classification By Material

• Rubber mount: Uses vulcanized rubber, which absorbs energy by deformation of the molecular structure, but high temperatures and oil erosion accelerate deterioration.
• Hydraulic mount: the shell is made of high-strength alloy (most of them use lighter aluminum alloy), the interior is filled with silicon-based damping fluid, vibration conduction delay of 0.2 seconds, commonly found in Mercedes-Benz, Lexus and other luxury cars.
• Polyurethane mounts: 8 times stiffer than rubber, but transmit more road noise, adding 15 dB to interior noise.
• Electromagnetic mounts: it will change the stiffness by electric current according to the road condition.

Classification By Structure

• Solid Mounts: Directly connected using metal, simple structure but no displacement space, racing-specific, vibration is so strong that it can loosen the screws in the car.
• Hydraulic Mounts: Internal double chambers + damping fluid, according to the frequency of vibration, automatically adjust the liquid flow rate, low-speed quiet, high-speed stability.
• Active Mounts (e.g. Cadillac MRC system): with an ECU control valve that scans the road 100 times per second and uses an electromagnetic field to change the softness of the mounts.

Rubber Motor Mounts

Rubber motor mounts, which account for 70% of the engine mount market, are centered on a “three-layer sandwich” structure:

1. The outer metal plate attaches to the frame.
2. The center rubber block absorbs vertical vibrations.
3. Built-in metal limits horizontal displacement.

Rubber fears two things:

• High temperatures: The rubber hardens and cracks in 3-5 years in engine compartments with prolonged 90°C+ environments;
• Oil erosion: If oil leakage drips on the rubber mount, the life span is directly halved.
   (Statistics: in cold regions, the average life of rubber mounts is 2 years longer than in the tropics.)

Adaptation scenario: Do you fit rubber engine mounts

• Mobility scooters with annual mileage <10,000 kilometres;
• Older cars on a budget (replacing the full rubber mounts costs about $300-600);
• Pickup/van owners who are not sensitive to noise.

Hydraulic Engine Mounts

The principle of damping inside the hydraulic motor mount:

1. Engine vibration squeezes the silicone oil in the upper chamber;
2. Silicone oil flows into the lower chamber through a narrow channel;
3. Fluid friction converts kinetic energy into heat energy for dissipation.

(Comparison of effects: 40% reduction in steering wheel vibration at 2000 rpm with hydraulic mounts compared to rubber mounts)

Cost of using hydraulic engine mounts

In the case of the BMW 5-Series, for example, the factory hydraulic mounts costs $280 per unit, but the 4S store charges a whopping $200 for replacement labor. Moreover, once the internal seals fail and lead to a fluid leak, the entire mounts is simply scrapped – that’s why a used car with the hydraulic mounts intact can be valued at an extra $1500.

Disadvantages of using hydraulic supports

• Risk of leakage: seal checking is recommended every 5 years.
• Decreased performance at low temperatures: Silicone oil viscosity increases at temperatures below -10°C, damping effect is discounted by 70%;
• It can only be replaced in its entirety and cannot be repaired individually like rubber mounts.

Polyurethane Engine Mounts

Why can’t you modify your car without urethane mounts?

The hardness of the polyurethane mounts is more than 3 times that of ordinary rubber mounts, which can completely suppress the horizontal shaking of the engine. When driving aggressively, the power output is more direct – actual test data shows that the acceleration time from 0-100km/h is shortened by an average of 0.3 seconds for vehicles with polyurethane mounts installed.

Its flaws are also obvious:

• 15 dB increase in interior noise (equivalent to switching from a library environment to a food market);
• The low-speed stutter is amplified, and it’s like riding a horse in traffic.
• The mounts need to be inspected every 2 years for deformation due to over-compression.

Installation Precautions

• The resonance zone of polyurethane engine mounts typically occurs at 1500-2000 rpm and can be mitigated by adjusting the mount mounting angle offset by 3-5 degrees.
• Be sure to replace the gearbox mounts at the same time, otherwise, there is a risk of breakage due to uneven forces.
• Avoid aggressive driving for the first 500 kilometers after installation to allow the material to gradually adapt to the stress distribution.

Electromagnetic (active) Motor Mounts

At the heart of the electromagnetic mount is a set of intelligent systems that can respond in milliseconds:

1. The body acceleration sensor scans the road 100 times per second.
2. The ECU analyzes the data and adjusts the magnetorheological fluid viscosity inside the mounts via a solenoid valve.
3. From detection to vibration to complete stiffness adjustment, the whole process takes only 20 milliseconds.

From supercars to electric cars

• Tesla Model S Plaid: Utilizes electromagnetic mounts to counteract high-frequency vibrations of the motor.
• Porsche 911 GT3: 300% stiffer mounts in track mode, 40% less cornering roll;
• Toyota Hydrogen Mirai: The unique pulsating vibrations of the hydrogen pump are actively counteracted by the mounts.

Which Motor Mount is Best for You?

Key Decision Points

1. Annual mileage: more than 20,000 kilometers/year, choose hydraulic mounts, and vice versa with rubber models.
2. Common RPM range: if it’s city driving (2000-3000 RPM), you need to focus on damping, and frequent highway running (4000 RPM+) you need to focus on torsional stiffness.
3. Maintenance budget: Hydraulic mounts replacement requires simultaneous ECU calibration, labor is 3 times more expensive than parts

A Guide to Avoiding the Pitfalls of Performance Tuning

• Front front-wheel drive cars: prioritize strengthening of the right side mounts (to withstand 70% of torque backlash)
• Rear-wheel-drive models: transmission mounts are more important than motor mounts
• Turbocharged cars: the temperature resistance rating of the mounts must be checked (temperatures exceeding 200°C in the vicinity of the exhaust gas turbine)

Cost-Effectiveness

typology	Lifespan (kilometers)	unit cost	Scenario
General rubber	60,000	$80	Prospective new cars within 5 years
hydraulic damping	120,000	$260	SUVs that frequently run long distances
Polyurethane Athletics	40,000	$500	A steel gun that goes off the track every month

Installation and maintenance of engine mounts

You Have to Pay Attention to These Issues

• Mounts bolts should never be tightened with an impact wrench (destroys torque yield bolt characteristics)
• Laser level error needs to be less than 0.5 ° (old technicians use the hanging line method instead of a more accurate)
• Grease should be lithium-based and high-temperature resistant (ordinary grease expands when it meets rubber)
• An engine support stand is required (to prevent the engine from falling during disassembly).

7 Secrets of Professional Technicians

1. Applying thread adhesive prevents bolts from loosening, but it must be medium strength (red) and not permanent (green).
2. Allow the engine to idle for 10 minutes after installation to allow the mounts material to fit naturally.
3. Four-cylinder cars are prioritized for removal starting from the exhaust side, V6 engines have to loosen the center bolt first;
4. Calibrated with a laser alignment gauge, 10 times more accurate than traditional plumb lines;
5. For winter installations, first heat the rubber to 20°C or more with a heat gun;
6. Hydraulic mounts need to sit for 24 hours after installation before driving aggressively.
7. Polyurethane mounts are sprayed with silicone grease every 6 months to prevent drying out.

Common Problems

“The 4S store told me to replace all of them, but the garage said to just replace one?”

Look at the wear position: if it is a longitudinal engine, the left and right mounts have different loads and must be replaced in pairs; transverse engines can be replaced individually, but check the preload of diagonal mounts

“The stiffer the brace the better?”

Laboratory tests have shown that:

• 50% increase in stiffness → engine vibration transmission rate reduced by only 8%;
• However, the load on the gearbox bearings is increased by 30% and the life is reduced by 40%.

CONCLUSION: It is safest to modify no more than 20% of the original hardness.

7 Signs Before a Stent Breaks

1. A muffled “thud” came from the engine compartment when I braked in D on the air conditioner.
2. There is a metallic pulling sound momentarily over speed bumps.
3. Unidentified oil stains at oil filter location (may have been squeezed by sinking engine);
4. Exhaust lugs break frequently;
5. The steering wheel resonates at a specific RPM range (e.g. 1800 rpm);
6. The hatch seam suddenly became larger;
7. Increased fuel consumption and no fault codes.

About VISTA MOTION

We specialize in manufacturing rubber vibration damping products for more than 20 years, and our engineers have very rich experience in the industry. We have our own factory and R&D center. We can also participate in the preliminary research and development of your new project. We can also customize rubber vibration damping products for you in various industries. Including Railway Vehicles, Construction Machines, General Engineering, Drive Engineering and many other industries.