MGB and MGB GT buyer's guide

Rubber bumper cars are just worse MGBs.

They sit higher and handle a little less sharply, but later examples have better cooling, revised anti-roll bars and more comfortable seats. Many owners lower them, and an unmodified rubber bumper car is now the less common sight.

A quiet engine is a healthy engine.

Some tappet noise is normal on a B-Series. A completely silent top end can mean the tappets have been set too tight, which can damage the cam followers and camshaft.

Shiny new sills mean the structure is sound.

Outer sills are often welded over rotten inner sills and castle rails. The outer panel tells you little about what is behind it.

Any MGB GT with a V8 is a factory GT V8.

Many V8 conversions exist. A factory car has its own chassis and engine numbering, and the MG Car Club V8 Register can help confirm identity.

Bodywork and structure

The MGB's body is its chassis, so this is where most of your time should go. Take a torch, a magnet and a mat to lie on.

• Sills: they are built in layers (outer sill, inner sill, a membrane and a castle rail between them). Bubbling where the front or rear wing meets the sill suggests the inner sill is poor.
• Look for new outer sills welded over old ones, and check that the sill drain holes are clear and in solid metal.
• Jacking points and the joint where the floor meets the inner sill, from underneath and inside the footwells under the carpet.
• Front inner wings and the trumpet sections at the top of the inner wing, plus the ledge at the top of the front arch where mud collects.
• Front wings at the headlamp bowls, the bottom rear corners and the arches; also the seams where the wings meet the scuttle.
• Rear wings are welded on, not bolted: check the top seams, the arch lips and the lower rear corners behind the wheels.
• Rear spring hangers, the floor around them and the chassis legs, plus the boot floor around the spare wheel well.
• Boot lid (roadster) and tailgate (GT) trailing edges, which are double skinned and rot from inside; filler is common here.
• GT: the bottom of the windscreen frame, the sunroof frame if fitted, and the rear screen seal, which can let water into the boot.

Engine

The 1.8 B-Series is strong when it has been serviced. Ask for a cold start if you can, and look at the oil before the engine runs.

• Dipstick oil: clean is good, milky residue suggests water contamination, black sludge suggests infrequent changes.
• Blue smoke on start-up or over-run points to worn valve guides or stem seals; smoke under acceleration suggests worn bores.
• Light tappet noise is normal. Total silence can mean overtight tappets.
• A rumble from the bottom end means worn main or big end bearings; a chatter at the front can be a worn timing chain.
• Oil pressure when warm: a healthy engine typically shows around 50 to 60psi when driving, with lower readings at idle. Low readings need explaining.
• Coolant should be clean, with no oil on the surface or in the filler; check for overheating in traffic and that the electric fan on later cars cuts in.
• Flat spots or poor throttle response usually mean worn or unbalanced SU carburettors; misfires and hard starting often point to ignition.

Gearbox and drivetrain

There are two main gearbox types, and overdrive adds its own checks.

• Early (pre-Mk2) three-synchro gearboxes have no synchromesh on first and are weaker in second. Check for crunching and jumping out of second or third.
• Whine in the gears, or a rattle in neutral that disappears when the clutch is pressed, suggests worn bearings. Some first motion shaft bearing noise is a known trait.
• Overdrive should engage and disengage promptly in third and fourth. Faults are usually electrical, often the solenoid or switch wiring, especially the gear lever switch on later cars.
• Overdrive that slips under load suggests wear inside the unit, which is a specialist job.
• Clutch: judder, slip, or a swishing noise from a worn release bearing. Clutch work means removing the engine or gearbox.
• Rear axle: a whine that rises with speed points to differential or bearing wear; check for oil leaks at the pinion and rear casing.

Suspension, steering and brakes

The front suspension is simple but needs regular attention, so wear here tells you a lot about past care.

• Kingpins need greasing every few thousand miles. Ask about it, look for fresh grease at the nipples, and check for play by rocking the front wheel top and bottom.
• Lever arm dampers: look for oil leaks and a bouncy, wallowing ride. Telescopic rear conversions are common.
• Clonks over bumps often come from worn anti-roll bar mountings or wishbone bushes.
• Rear leaf springs can sag or seize; the car should sit level. Check the shackles and bushes.
• Rubber bumper cars that have been lowered: check the work looks professional and that nothing is loose.
• Brakes are front discs and rear drums throughout. Check for pulling, a spongy pedal, scored or rusty discs and leaking rear wheel cylinders, especially on cars that are rarely used.

Electrics and instruments

MGB electrics are simple, so most faults are earths, old wiring and switches rather than component failures.

• Work every switch: lights, indicators, hazards, wipers on both speeds, heater fan and horn.
• Watch for one circuit affecting another, for example indicators dimming the rear lights, which suggests poor earths.
• Look behind the dashboard and in the engine bay for brittle insulation, scorched connectors and amateur additions.
• Check the overdrive switch and its wiring, and that the temperature, oil pressure and fuel gauges all read sensibly.
• On later cars, confirm the electric cooling fan cuts in.

Interior and trim

Interiors changed a great deal over 18 years, and correct trim matters to originality.

• Early cars have leather seats and a metal dash; later ones moved to vinyl, then to a plastic fascia and cloth seats. Check the interior suits the car's year.
• Damp carpets and rusty seat runners point to leaks from the windscreen seal, hood, door seals or heater.
• Roadster hood: check the frame, the fabric, the rear window and that it fits and seals.
• GT: check the headlining for sagging and stains, and the sunroof for leaks and operation.
• Chrome condition matters on chrome bumper cars because replating is costly.

Paperwork and originality

With so many conversions and rebuilds, the paperwork is part of the car.

• Check the chassis number on the car against the V5C, and the engine number against any records.
• A Heritage Certificate from the British Motor Museum at Gaydon confirms build date, original colours and engine number from factory records.
• For a GT V8, MGC, Jubilee or LE, ask the relevant club register to help confirm the car is genuine.
• Look for receipts for structural work, especially sills, with photographs if possible.
• If the car is on a Heritage shell, find out when it was fitted and by whom.
• Note modifications: chrome bumper conversions, engine upgrades, five-speed gearboxes, electronic ignition. Some are welcome, but they should be declared.

Where do MGBs rust?

The sills (outer, inner and castle rail), where the floor meets the sill, the front inner wings and trumpet sections, front wings around the headlamps, rear wing seams, rear spring hangers, the boot floor and the bottom of the tailgate or boot lid.

Should I buy a chrome bumper or rubber bumper MGB?

Chrome bumper cars are lower and generally preferred for looks and handling. Later rubber bumper cars, especially from 1977, have better cooling and revised suspension. Body condition matters more than bumper type.

Roadster or GT?

The roadster is the classic open sports car. The GT is more practical, with a hatchback, occasional rear seats and better weather protection, and its sills are simpler to repair because a roadster body needs bracing during sill work.

Is an MGB a good first classic car?

Yes, for many people. It is simple, parts are easy to find, and the clubs offer plenty of help. Have a specialist inspect the structure before you buy if you are unsure.

What is the difference between the three-synchro and four-synchro gearbox?

Cars before the Mk2 of late 1967 have no synchromesh on first gear and a weaker gearbox, particularly second gear. The later all-synchromesh box is tougher and easier to use in traffic.

How do I tell a real MGB GT V8?

Factory cars were GTs only, built from 1973 to 1976, with their own chassis and engine numbering. Check the numbers against the V5C and ask the MG Car Club V8 Register for help.

What is a Heritage shell MGB?

A car rebuilt on a new bodyshell made by British Motor Heritage, which started remanufacturing MGB shells in 1988 using original tooling. The shell is new, but the rest of the car depends on the rebuild.