The exhaust manifold and its supporting hardware see the highest temperatures and the most aggressive vibration of any external component on the engine. This section gathers the supporting components needed alongside the headline manifold and exhaust-system parts, the fibreglass heat wrap and its ties, the brass manifold nuts and studs, the heat-shielding and finishing products, and the various clamps and fixings that hold the system together.
Manifold Heat Wrap
Fibreglass heat wrap is the woven insulating material wound around the exterior of a tubular exhaust manifold, retaining exhaust heat inside the manifold rather than allowing it to radiate into the engine bay. The benefit is twofold, the retained heat inside the manifold promoting faster gas-flow through the system, as hotter gas flows faster and improves exhaust scavenging, and the reduced heat in the engine bay protecting the carburettors, fuel lines, ignition components, and wiring from radiated heat. This thermal management benefit is particularly valuable on installations where the inlet and exhaust manifolds sit on the same side of the engine, as on the C-series MGC and the MGA, where the proximity of the hot exhaust to the carburettor float chambers can cause fuel vaporisation in hot weather or slow traffic, producing rough running, hesitation, and hot-start difficulty. The wrap is supplied in 50mm rolls of around 15 metres, applied to a clean, cool manifold by winding it tightly with around half-width overlap on each turn, secured with stainless steel locking ties at the ends and at intervals along its length.
When first heated to operating temperature the wrap will typically smoke and darken as the binding agents cure, which is normal and clears within the first few minutes of running. The wrap is suited to tubular performance manifolds, which run hotter than the original cast-iron items, and is generally not applied to original cast-iron manifolds with their integrated heat-shield arrangements.
Brass Manifold Nuts & Studs
Brass manifold nuts are the period-correct fixing for the manifold-to-cylinder-head connection on every classic-MG application, as brass does not seize to the steel studs in the cylinder head in the way that steel nuts eventually do. The dissimilar metal contact, combined with the periodic heating and cooling of the manifold, would weld a steel nut to its stud over time, making removal extremely difficult, whereas brass nuts shed material progressively rather than seizing solid, so when the time comes to remove the manifold the nuts come off cleanly.
Replacement studs in the appropriate length and thread specification are stocked alongside the nuts for owners renewing the complete fixing assembly during a major engine service, and anti-seize compound should always be applied to manifold stud threads during assembly.
Heat Shielding & Finishing
Aluminised fabric sheeting, supplied in one-metre square sheets, provides additional thermal protection for the engine bay and bonnet underside, the reflective aluminium surface bouncing radiant heat back towards its source while the fabric substrate provides insulation against conducted heat, and can be cut to line the bonnet above the exhaust area, to shield the carburettor float chambers, or to protect wiring and fuel hoses running near the manifold. High-temperature exhaust paint is available in black, silver, red, and white for refinishing manifolds and system components that reach temperatures where conventional paint would burn off immediately, and exhaust jointing seal provides a gas-tight connection at the manifold-to-downpipe and pipe-to-silencer joints, remaining flexible at operating temperature to accommodate the thermal expansion and contraction that occurs on each journey.
Clamps & Mounting Hardware
The clamps and supporting hardware cover the manifold-to-downpipe connection, the heat-shield mounting hardware for cars with original heat shields, and the various clamps and rubber mountings that complete an exhaust installation. Exhaust clamps are typically U-bolt or band-clamp type at each section joint, and rubber mountings sit between the silencer-mounting brackets and the pipe, absorbing vibration and allowing controlled thermal expansion, both wearing independently of the pipework as rubbers harden and crack with heat and age while clamp studs rust through after years of road-salt exposure. Renewing clamps and rubbers as part of a new-exhaust installation is normal practice and avoids part-way leaks developing in the first months of service from worn fittings reused on a new system, with system-specific exhaust fitting kits bundling the correct combination of clamps, mountings, and fixings for each application.