The MG Midget exhaust system underwent four distinct configurations during production, determined by engine size, chassis number range, and steering specification. Mild steel replacement systems are available alongside Double S stainless steel systems with lifetime guarantee. Identifying the correct system type is essential when ordering, the front pipe-to-manifold joint, silencer arrangement, mounting bracket positions, and fitting hardware all differ between types.
Type 1 Exhaust (1967 to 1969)
Type 1 was a single-box system with a flared front pipe connection, fitted to right-hand drive 1275cc cars from 1967 to 1969. The flared joint relies on the clamp compressing a flared collar against the manifold bell, if the flare is damaged or the bell is cracked, the joint will never seal regardless of clamp tension, and renewal of either or both components will be necessary.
Type 2 Exhaust (1970 to 1972)
Type 2 was a twin-box system with a flared front pipe joint to the bell-type manifold, fitted to UK right-hand drive cars from 1970 to 1972 and to European left-hand drive cars from 1967 to 1972. The system uses a resonator and silencer arrangement with rear mounting brackets bolted to the boot floor. The bracket specification varies with chassis number, so the chassis number should be quoted when ordering.
Type 3 Exhaust (1973 to 1974)
Type 3 introduced a three-stud flanged connection with an olive seal at the manifold joint, replacing the earlier flared arrangement. Fitted from 1973 to 1974 for both right-hand drive and non-North American left-hand drive cars. The olive must be replaced whenever the joint is disturbed, reusing a compressed olive will cause leaks and the characteristic ticking sound of an exhaust manifold leak.
Type 4 Exhaust (1500)
Type 4 was the 1500 twin-box system fitted from 1975 to 1979, using a gasket-sealed downpipe joint to the cast iron manifold. The rear section was revised at chassis number GAN6-200001 (August 1977) and the silencer rear mounting changed at GAN6-169792. The chassis number must be quoted when ordering 1500 exhaust components to ensure the correct configuration.
Exhaust Manifolds
Two cast iron exhaust manifolds were fitted to the 1275cc: the bell-type (accepting the flared pipe of Types 1 and 2) and the flanged three-stud type (accepting the olive-sealed pipe of Type 3). The 1500 manifold is a completely different casting with its gasket-sealed downpipe flange. Brass nuts are essential on all manifold studs, they resist heat-cycling corrosion and make future removal far easier than steel nuts, which seize on the studs and frequently shear during removal.
Performance Manifolds
Tubular performance manifolds in stainless and mild steel are available for the 1098cc, 1275cc, and 1500cc applications, offering improved exhaust scavenging and increased power compared to the original cast iron manifolds. When fitting a tubular manifold, carburettor needles should be changed to a richer profile to compensate for the improved exhaust gas flow, the engine will draw more air and require correspondingly more fuel to maintain the correct mixture ratio.
Stainless Steel Exhaust Systems
Double S stainless steel systems are manufactured in the UK from 309 and 401 grade stainless steel, with mirror-finish silencer bodies and a lifetime guarantee against penetration. Standard systems provide the traditional MG exhaust note; sports systems offer a sportier sound with improved performance. Configuration options include single-box, twin-box, and twin-box with twin tail pipes, with variants for both bell-type and flange-type manifold connections.
Exhaust Fitting
When replacing an exhaust system, hanging brackets, clamps, rubber bushes, and insulation washers should all be inspected and renewed alongside the system itself, old rubber bushes hardened by heat cycling will not absorb vibration effectively and lead to premature system failure at the joints. All joints should be left loose until the complete system is correctly positioned and aligned, then tightened progressively from the manifold rearward to avoid pre-loading the joints. Dedicated fitting kits tailored to each system type and chassis number range are available, containing all the clamps, brackets, rubber mountings, and fixings needed for a complete installation.