Performance Motor Mounts

Think if your job were to hold in place a several hundred ton piece of metal. Now consider that this hunk of metal had inside of it routine explosions, and that the metal would often travel at nearly one hundred miles per hour. You have just imagined the job of a performance motor mount.

The number one job of a performance motor mount is to hold an engine in place and tolerate the vibrations and movements that come with the movements of the motor, namely the movements of the cylinder. The rapid firing of the cylinder exerts weight downward, upward, and all over, shaking the engine with each pulse.

Over time, engine mounts are prone to wear, tear, or damage. This is due to the extreme conditions under which they operate (was it mentioned they work in hot and cold, too?) While ordinary passenger cars experience operating conditions of their own that are not very conducive to comfort, performance automobiles cause wear and tear that are unique of their own.

Performance Motor Mounts
Performance motor mounts are often found in high-RPM, high-torque automobiles or in heavy machinery. If used in racing vehicles, as performance engine mounts so often are, they must be both light and effective. Light and effective are two things not often combined. It is far easier to make a mount that is heavy and effective, though heavy is not conducive to high speeds, nor is thick metal very good at dispersing the heat of an engine.

Usually made of rubber and metals (steel and aluminum are common) the motor mount should absorb most vibration coming from the engine, as well as insulate the engine from the vibrations of the road. Just as it is dangerous to exert the full force of a high-powered engine to the frame of a vehicle, it is equally dangerous for an engine to absorb the vibrations from the common street pot hole.

Replacing Broken and Worn Mounts
Motor mounts have to work as a team to secure a vehicle's engine. With that understanding, it is important to realize that when one mount is not working properly, then it is also highly likely that the other mounts securing the same engine have been working overtime.

In doing so, the mounts that have absorbed much of the shock and vibration will wear very quickly to a point at which the others will then bare much of the burden. Have you ever helped carry a heavy item with someone else? The very second one person stops carrying their share, all the weight he or she was holding is then transferred to everyone else. However, unlike this example, the item the group is carrying is likely not vibrating, instead it is just very heavy. An engine is very heavy, always in motion, and the weight is never evenly dispersed.

Typically, motor mounts are standardized by weight and the parts used to attach the engine to the mount. However, the quality, capacity for stress, and the strength of the metals vary greatly. Performance engine mounts are evaluated with a durometer which tests the tensile strength of a particular metal product.

The rating are assigned with a number ranging generally from 50-90A. On the low end up to 65A are ratings for daily driving of a high performance vehicle. While the engine in this car may be roaring, and creating plenty of vibrations, the daily driving speed makes these suitable engine mounts for low-speed, low-stress driving.

In the middle range are motor mounts for high-speed drag strips and short-term car sprints. These mounts can handle up to 700 horsepower, but are stiffer, and not always recommended for street applications.

Finally, the high-end offers excellent stiffness, but the cost of limited use. These are suited for high speed races, but should never be used on the street due to the stiffness of the metal. Stiff metals are prone to breaking when the weight of the engine shifts quickly as it does on common street corners.