Classic MGs were not built with substantial soundproofing, the open-roadster character of most applications, the production economics of the era, and the absence of modern noise-control materials all meaning that cabin noise levels were dramatically higher than modern cars achieve. The thin steel panels, open transmission tunnel, and minimal factory insulation allow a considerable amount of road noise, transmission noise, and panel vibration into the cabin, which on longer journeys or in modern motorway conditions can be tiring across an extended drive. Soundproofing materials installed during interior restoration substantially reduce the noise levels in the cabin, transforming the practical reality of using the car on longer journeys and the amount of conversation possible at speed.
Tailored Interior Kits
A tailored interior soundproofing kit is manufactured from jute with a crumb-polyurethane base layer formulated with resistance to oil, cut to fit the floor, tunnel, and body sides of the chosen car, most effectively fitted during a full retrim when the floor is already stripped, and providing a meaningful improvement in refinement at a sensible cost. Underfelt is the layer between the bare floor pan and the carpet that absorbs higher-frequency engine and exhaust noise transmitted up through the floor and provides thermal insulation that reduces heat transfer from the transmission tunnel and exhaust system into the cabin, a quality felt being a thick natural- or synthetic-fibre material that follows the contours of the floor pan and tunnel, with modern foil-faced versions adding a reflective layer that reduces radiant heat from the exhaust below the floor, particularly valuable on cars with heat-shield issues or hot-running exhausts.
Sound-Deadening Sheet
For owners who want the most complete acoustic treatment, a butyl-rubber sound-deadening sheet with an aluminium face adheres directly to the bare steel body panels, applied to the floor pans, gearbox tunnel, bulkhead, and rear cockpit area, where it provides maximum noise reduction, increases the structural stiffness of the panels to reduce drumming and resonance, and protects the steel from condensation and corrosion by preventing air and moisture reaching the metal surface. A panel without sound deadening rings like a bell when struck with a knuckle, while a panel with quality damping material damps the ringing to a dull thud, with corresponding reduction in noise transmitted into the cabin. Over this, a thermal liner provides an additional layer of insulation that reduces the heat transmitted from the tunnel and floor into the cockpit, available in several thicknesses, the thinnest for contoured areas like the gearbox tunnel and the thicker grades for flat sections like the floor pans, with a sealing tape joining adjacent sections to complete the moisture barrier.
Doors, Bulkhead & Bonnet
Inner door skins benefit from sound-deadening pads to reduce the door's contribution to cabin noise, a quality installation deadening the panel sufficiently that the door no longer rings under road inputs, with the rear bulkhead on roadster applications and the rear hatch panel on GT applications benefiting from similar treatment, particularly important on cars used on motorways where rear-end exhaust noise can be significant. Anti-vibration adhesive pads are stocked for fitting inside door skins, floor pans, inner wings, and the GT roof, addressing panel resonance at source. A bonnet soundproofing kit with self-adhesive backing reduces heat and noise transmission from the engine bay into the cabin and is straightforward to fit without a full strip-down. Complete soundproofing kits, matched packages including the appropriate quantities of material, are stocked for the principal applications, with traditional jute-based kits providing good thermal and acoustic insulation at a fraction of the cost of the butyl-based materials, though without the corrosion-prevention benefit.