Insulation and Sound Deadening for A Quiet Ride

By Stephen Kassis

Our old cars are a lot of fun but one thing they are NOT is quiet. Sound deadener is the best solution for a noisy ride. There are many brands and types of sound deadening material on the market today. We will look at the different materials available and the reasons to use them. Hopefully, you are reading this before your interior has been installed because that is the best time to install the sound deadener.

Most sound deadeners will also have an added benefit of insulating in addition to keeping noise down. Products like Dynamat’s Xtreme and R-Blox are made of a butyl backing with an aluminum facing. These products are easy to install with just a utility knife and a small roller to press it in place.

Clean the mounting surface thoroughly and remove all dirt, rust, oil, etc. to assure a good bond with the product. A clean, fresh (but cured) painted surface will give the best results. Always try to install this material in temperatures above 60 degrees F. If you must work in lower temperatures, use a hair drier or heat gun to heat the material and mounting surface before attempting installation. Good adhesion is vital to a long lasting job.

Trim out a piece of the material. Lay it in place to check the fit. You do not have to cover every square inch of surface, but get as much covered as possible. Cut around any bolts or other objects that prevent the material from laying flat on the metal. This is especially important when there will be carpet or a firewall insulator going over the sound deadener. Peel the backing and carefully lay the piece in place. Use the roller to press firmly onto the metal. If any bubbles develop, cut a small slit in the sheet and press down again with the roller. This material can be used on the floor, inside firewall, headliner area (on metal roof vehicles), inside doors, or any metal surface that can be reached and covered.

An economical woven fabric insulated pad (SA-58) is great to use as a backing for floor mats or carpet. For wood bodied cars in the headliner area where you cannot use the butyl backed product, an excellent product is Dynamat Dynaliner. This product is an ultra-lightweight closed cell foam. Dark gray in color, Dynaliner is self-adhesive with a high-temperature acrylic adhesive. You can also use a staple gun for installation on wood bodied cars.

Hoodliner is another quality product from Dynamat. It is a polyester urethane based product with aluminized facing and pressure sensitive adhesive, thermo-acoustic foam. This product is designed to be installed in the engine compartment on the underside of the hood. Both material and adhesive are designed for high and low heat conditions typical in the hood area.

No matter where you are trying to put the sound deadening material, there will always be those hard to reach areas – in the wheel wells, down inside the doors, up under the dash – these areas can be handled with sprayable liquid dampeners. Dynamat and R-Blox both make them but they require special sprayers for application. Another easy alternative is to use aerosol undercoating. It has very good sound dampening qualities when used in hard to reach areas.

Replacing the old firewall insulator is a big improvement over the original cardboard piece that is probably torn and falling apart. After removing everything (including wiring) from the firewall area, clean and paint as necessary. Install a sound deadening material such as Dynamat Extreme or R-Blox, then cover with a new ABS plastic firewall kickboard. Not only will this make the firewall look clean, it will lower the engine noise and cut down on heat transfer from the engine compartment.

If you want pre-cut insulation and sound deadening kits, Quiet Ride Solutions makes excellent quality pre-cut, ready to install Acousti-Shield kits for 1933-1964 full size passenger cars and 1936-1987 trucks. Each kit comes with illustrated instructions, pre-sized sound dampener pads, pre-cut heat shield absorber panels, spray adhesive and aluminum sealing tape.

No matter which product you choose, the money and time you will spend on installing sound deadener and insulation will be enjoyed each time you take your old car for a ride. It is the single best investment you will make in your restoration.