MG MGB B-Series Engines
from £2,450 to £4,800
Rebuilt units from £2,450 · Common codes: 18G, 18V, 18GK, 18V-Z
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MG MGB Engine Replacement - Rebuilt & Performance Options Available
Get quotes from trusted UK MG MGB engine specialists. Compare rebuilt and performance reconditioned prices for 18V and B-Series - 1.8L straight-4 covered. Find UK performance engine specialists.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
MG MGB GT V8 Engines
from £4,200 to £8,500
Rebuilt units from £4,200 · Common codes: 35S4, 35SD
MG MGB Emissions-Compliant Engines
from £2,650 to £5,100
Rebuilt units from £2,650 · Common codes: 18V-Z, 18GK, 18GH
Instant engine replacement quote - 100% free, no obligation
Engine replacement near me - UK-wide specialist network
Compare reconditioned, rebuilt & used engine prices
Supply & fit available - parts and labour from vetted specialistsInstant engine replacement quote - 100% free, no obligationEngine replacement near me - UK-wide specialist networkCompare reconditioned, rebuilt & used engine pricesSupply & fit available - parts and labour from vetted specialistsHow It Works
3 Simple Steps3 Simple Stepsto Finding the Best MG B Replacement Engineto Finding the Best MG B Replacement Engine
12-Month Warranty
Supply & Fit Available
Nationwide Delivery
Trusted UK Suppliers
Most replacements completed within 3-5 days.
Live UK Engine Market Data
Average Market Prices
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↻ Last updated: 4 Aug 26, 9:26
Customer Reviews
Trusted by MG B Owners Across the UK
Rated 4.8 out of 5 by 1,081 verified customers who sourced reconditioned and used MG B engines through EngineMarket.
4.8
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★★★★★
“Thanks to EngineMarket, I saved over £1,200 on my engine replacement and got matched with a great local specialist within the hour.”
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“Got three quotes within an hour and chose the best deal easily. The whole process was quick, clear and stress-free.”
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“I wasn't sure what I needed, but they helped me identify the right engine and connected me with a trusted garage.”
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“Thanks to EngineMarket, I saved over £1,200 on my engine replacement and got matched with a great local specialist within the hour.”
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Variants We Cover
MG MGB Engine ReplacementAll Variants Covered
MG MGB Roadster
18G/18V 1.8L Petrol
Rebuilt Engines: £2,450-£4,500
MG MGB GT
18V 1.8L Petrol
Rebuilt Engines: £2,450-£4,200
MG MGB GT V8
35S4 3.5L Petrol
Rebuilt Engines: £4,200-£8,500
MG MGB Chrome Bumper
18G 1.8L Petrol
Rebuilt Engines: £2,650-£4,500
MG MGB Rubber Bumper
18V/18V-Z 1.8L Petrol
Rebuilt Engines: £2,450-£4,200
MG MGB Limited Edition
18V 1.8L Petrol
Rebuilt Engines: £2,850-£4,600
MG MGB 18G Early Model
18G 1.8L Petrol
Rebuilt Engines: £2,750-£4,600
MG MGB 18V Late Model
18V 1.8L Petrol
Rebuilt Engines: £2,450-£4,200
MG MGB US Specification
18V-Z 1.8L Petrol
Rebuilt Engines: £2,650-£4,400
MG MGB Overdrive Compatible
18V 1.8L Petrol
Rebuilt Engines: £2,550-£4,300
MG MGB Pre-Emissions
18G/18V 1.8L Petrol
Rebuilt Engines: £2,650-£4,500
MG MGB Emissions-Compliant
18V-Z 1.8L Petrol
Rebuilt Engines: £2,650-£4,400
Not sure which variant your MG MGB is- Enter your registration number above - we'll identify the exact sub-model, engine code and compatible replacement options instantly.
B
Engine Codes
MG MGB Engine CodesFull Technical Specifications & Replacement Guide
Every engine code fitted to the MG MGB across all generations, with technical specs, compatible variants and trims, known failure points, and average rebuilt prices from UK specialists. Select any engine code to compare quotes.
Petrol Engines
Extracted from detailed petrol and performance engine families across MG B variants.
18G - 1.8L Petrol
Main replacement demand comes from timing-chain, cooling-system and performance thermal-management faults.
Compatible variants
Roadster (1962-1967)GT (1965-1967)Chrome Bumper models
Avg. rebuilt price
£2,750 - £4,600
Supply only
Technical specifications
- Fuel type
- Petrol
- Engine size
- 1.8L
- Power output
- 95 hp
- Years fitted
- 1962-1980
Common failures
- ●Main replacement demand comes from timing-chain, cooling-system and performance thermal-management faults.
- ●Confirm exact engine code and fitment before ordering.
- ●Ask for warranty and supply & fit terms.
Not sure which engine code?
Can't find your engine code- Enter your registration number above - we'll instantly identify the exact unit, its technical specifications, and live replacement prices from UK MG MGB engine specialists. Every rebuilt engine comes with a minimum 12-month unlimited mileage warranty.
B
Common Problems
MG MGB Engine Problems - What It Costs to Fix & When Replacement Makes Sense
The MG MGB's B-Series engines are robust but age-related failures are common - oil leaks from rear main seals, overheating from aged cooling systems, and bearing wear at high mileage dominate replacement enquiries. Every rebuilt engine supplied through EngineMarket includes upgraded internal components designed to address the original failure point - plus a...
Rear Main Seal Oil Leaks - Why MG MGB B-Series Engines Drip Oil
Rear Main Seal Oil Leaks
Most affected vehicles
MG MGB RoadsterGT (1962-1980
MG MGB Roadster, GT (1962-1980, 18G & 18V B-Series)
Failure mileage range
50,000-80,000 miles
Typical failure window
Root cause
Original cork/rubber rear main seal design degrades with age and heat cycling, allowing oil to escape between engine block and gearbox.
Repair options & estimated costs (UK ranges)
| Repair tier | Dealer price | Specialist price | What it involves | Longevity / suitability |
|---|---|---|---|---|
| Minor - Seal Replacement Only - Remove gearbox, replace rear main seal | £850 - £1,400 | £550 - £950 | Gearbox removal, seal replacement, reassembly, oil refill | Temporary fix; other aged seals may fail soon after |
| Intermediate - Full Seal Kit - Replace all major oil seals during rebuild prep | £1,800 - £2,900 | £1,200 - £2,100 | Engine strip to short block, replace rear main, rocker, sump seals | Better value if planning partial rebuild; addresses multiple leak points |
| Full Replacement - Rebuilt / Reconditioned Engine - Complete unit with upgraded seals | £2,450 - £4,500 | £2,450 - £4,200 | Supply & fit rebuilt B-Series with upgraded rear main seal design, bench tested | Best long-term solution; eliminates leak risk with warranty coverage |
Our recommendation
On a classic MGB worth £8,000-£25,000, a full rebuilt engine with upgraded seals offers better value than repeated seal replacements. If the engine is otherwise healthy and mileage is under 60k, a specialist seal replacement may suffice.
Compare rebuilt B-Series engine prices for your MG MGBReplacement Engine Options
MG MGB Engine TypesOptions, Costs & What to Expect
Every MG MGB engine type is available through our UK network with typical price ranges based on variant, engine code and budget.
MG MGB Reconditioned Engines (Recon)£2,450 - £4,500((supply only))
MG MGB Rebuilt Engines£2,650 - £4,800((supply only))
MG MGB Used Engines£1,200 - £2,800((supply only))
MG MGB Remanufactured Engines£3,200 - £5,500((supply only))
MG MGB Refurbished Engines£2,100 - £3,900((supply only))
Compare MG B engine prices with vetted UK suppliers
All engine types include a minimum 12-month unlimited mileage warranty when sourced through EngineMarket. Prices are typical UK market ranges based on historical quote data from our network and depend on exact engine code, variant, mileage and supplier. Use our free comparison tool above - enter your registration to get tailored quotes for your specific MG MGB within hours.
Engine Sizes
MG MGB Engines by SizeFind the Right Displacement for Your Variant
Every displacement fitted to the MG MGB is listed below, with compatible engine codes, production years and common failure notes to help identify your replacement engine.
The 1.8L B-Series inline-four powered over 90% of MGB Roadsters and GTs from 1962-1980, offering simple OHV design, reliable torque and widespread parts availability for classic restorations across chrome and rubber bumper eras.
⚙
Engine Code(s)
18G, 18GA, 18GB, 18GD, 18GE, 18GF, 18GG, 18GH, 18GJ, 18GK, 18V, 18V-Z
▣
Compatible Models (UK)
Roadster (1962-1980), GT (1965-1980), Limited Edition (1979), Chrome Bumper (pre-1974), Rubber Bumper
ϟ
Power output
Verified by registration
△
Common Failure Points
Rear main seal oil leaks, cooling system overheating, bearing wear at high mileage
Production Years: post-1974
Compare MG MGB 1.8L petrol engine pricesFuel Type
MG MGB Engines by Fuel Type
Choose your MG MGB engine by fuel type to compare realistic replacement prices, known issues, and compatible UK supply options - from early 18G B-Series to the specialist Rover 3.5L V8.
MG MGB Petrol Engines
PetrolAll MG MGB models were petrol-powered, dominated by the 1.8L B-Series inline-four with the rare 3.5L Rover V8 reserved for the GT V8 performance variant.
Common MG MGB Petrol Engine Families
- •18G/18V B-Series - most common replacement engine (Roadster/GT), oil leak and overheating risks
- •18V-Z emissions B-Series - late-model rubber bumper variants, carburettor calibration sensitivity
- •35S4/35SD Rover V8 - GT V8 specialist units, aluminium block cooling considerations
Found In
- •MGB Roadster (1962-1980) - 18G (early), 18V (late)
- •MGB GT (1965-1980) - 18G/18V, 35S4/35SD (V8 models)
- •MGB GT V8 (1973-1976) - 35S4/35SD Rover 3.5L aluminium
Known For
- •Simple OHV B-Series design with excellent parts availability for classic restorations
- •Rear main seal and cooling system failures dominate high-mileage replacement enquiries
- •Rover V8 GT models command premium pricing but require specialist V8 expertise
Typical Petrol Models
- •Roadster (Chrome Bumper)
- •Roadster (Rubber Bumper)
- •GT (Chrome Bumper)
MG MGB Petrol Engines
PetrolAll MG MGB models were petrol-powered, dominated by the 1.8L B-Series inline-four with the rare 3.5L Rover V8 reserved for the GT V8 performance variant.
Common MG MGB Petrol Engine Families
- •18G/18V B-Series - most common replacement engine (Roadster/GT), oil leak and overheating risks
- •18V-Z emissions B-Series - late-model rubber bumper variants, carburettor calibration sensitivity
- •35S4/35SD Rover V8 - GT V8 specialist units, aluminium block cooling considerations
Found In
- •MGB Roadster (1962-1980) - 18G (early), 18V (late)
- •MGB GT (1965-1980) - 18G/18V, 35S4/35SD (V8 models)
- •MGB GT V8 (1973-1976) - 35S4/35SD Rover 3.5L aluminium
Known For
- •Simple OHV B-Series design with excellent parts availability for classic restorations
- •Rear main seal and cooling system failures dominate high-mileage replacement enquiries
- •Rover V8 GT models command premium pricing but require specialist V8 expertise
Typical Petrol Models
- •Roadster (Chrome Bumper)
- •Roadster (Rubber Bumper)
- •GT (Chrome Bumper)
Not sure which fuel type your MG MGB has- Enter your registration number above to instantly identify your engine code, fuel system and compatible replacement options - all backed by a minimum 12-month unlimited mileage warranty from UK MG MGB specialists.
Engine YearsGet quotes for 1962-1967 MG MGB replacement engines →
MG MGB Engines by YearWhat Was Fitted & WhenMG MGB Engines by Year - What Was Fitted & When
This section covers all major engine changes across the MG MGB's 1962-1980 production timeline, organised so classic car owners can quickly identify their engine and compare rebuilt prices from UK specialists.
⚙Key Changes
- ✓MGB Roadster launched (1962) with 18G B-Series 1.8L petrol engine
- ✓MGB GT coupe variant introduced (1965) sharing the 18G powerplant
- ✓Original cork rear main seal design and composite head gasket specification
▣Main Engines
18G- 1.8L petrol (Roadster 1962-1967, GT 1965-1967)
▰Popular Models
- •MG Roadster (1962-1967)
- •MG GT (1965-1967)
🔧Known For
- ✓Simple, robust B-Series design with excellent parts availability today
- ✓Rocker cover and rear main seal oil leaks common on high-mileage examples
- ✓Chrome bumper styling highly prized by concours restoration enthusiasts
Engine Codes Covered:
18G18GA18GBNot sure which year your MG MGB was built- Enter your registration number and we'll identify the exact engine, model year, and compatible replacement options instantly - all backed by a minimum 12-month warranty from UK MG MGB specialists.
FAQ