Rebuilt MG MGB Engine for Sale - Save Up to 60% UK Wide
Compare Prices & Save on MGB engines. Rebuilt B-Series I4 & Rover V8 units for MGB chassis (1962–1980) with 12m Unlimited Mileage Warranty.
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MG MGB Specialists
Expert Solutions for Every MGB – 1.8L Roadster to GT V8
Need a reliable replacement engine for your MG MGB?
Engine Finders specializes in MGB engines with solutions covering common issues across all variants,
from classic 1.8L Roadsters to high-performance GT V8s.
- ✔ Full MGB Engine Range – 4-cylinder & V8 engines across all generations
- ✔ Series-Wide Calibration – Correct tuning and ECU mapping for every MGB chassis
- ✔ MGB Pricing Advantage – Save significantly vs dealer on rebuilds and replacements
MG MGB Replacement Engines Options - Verified Units (UK Supply)
All engines bench-tested, VAT-inclusive, with 12-month warranty. MoT-compliant. Nationwide delivery. Direct OEM fitment for ADO23 and GHN/GHD.
B-Series units rebuilt with modern lead-free valve conversions and reinforced seals.
Machined to zero-mile specs, solving classic oil pressure drop and overheating issues.
Inspected 1.8L units with refreshed crank bearings and timing gear restoration.
Direct-fit B-Series and V8 options for standard or rubber-bumper MGB variants.
Chemically cleaned 18V castings, performance-tuned for optimal classic motoring reliability.
Sourced B-Series 1800 units with verified internal health and compression testing.
MG MGB Compatible Engine Codes & Average Prices on Rebuilt Units
All engines professionally reconditioned, bench-tested, and supplied with 12-month warranty. Direct OEM fitment. VAT-inclusive. Nationwide UK delivery.
Why Choose Engine Finders for Your MG MGB Engine?
Engine Finders connects UK drivers with vetted specialists for reliable, reconditioned MG MGB replacement engines. Covering the full series from the 1.8L inline-four B-Series to later performance upgrades, we address common issues such as timing chain elongation, oil pump wear, and head gasket leaks. Whether facing carburettor tuning challenges or coolant circulation faults, our series-level expertise delivers comprehensive, long-lasting solutions for all MGB variants.
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✔ MGB-Wide Timing Chain & Tensioner Service
Across all B-Series 1.8L engines, timing chain elongation and tensioner wear (OEM 18G623) are common. Engine Finders provides series-level replacements to restore reliable timing performance for every MGB variant.
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✔ Oil Pump & Lubrication System Rebuilds
All MGB engines share oil pump vulnerabilities (OEM 18G1341), leading to low pressure and premature wear. Engine Finders provides full lubrication system rebuilds for series-wide reliability.
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✔ Cylinder Head & Gasket Repairs
Head warping and gasket failures affect all 1.8L B-Series engines (OEM 18G614). Engine Finders carries out series-specific head repairs, ensuring consistent compression and preventing leaks across the MGB range.
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✔ Carburettor & Fuel System Restoration
Twin SU carburettors in all MGB variants suffer wear and misalignment (OEM 18G296). Engine Finders performs series-level rebuilds to restore optimal fuel delivery and throttle response.
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✔ Cooling System & Water Pump Maintenance
Water pump and thermostat wear is common across all MGB engines (OEM 18G1243), risking overheating. Engine Finders provides series-approved upgrades to maintain reliable cooling for every variant.
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✔ Series-Level Ignition System Overhaul
Distributor and ignition component wear affects the entire MGB series (OEM 18G2090). Engine Finders ensures precise series-wide ignition rebuilds for consistent performance and smooth running.
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✔ Exhaust & Emissions Component Servicing
Exhaust manifolds and emission components (OEM 18G721) degrade similarly across all MGB variants. Engine Finders performs series-focused repairs and replacements to maintain compliance and engine efficiency.
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✔ Series-Wide Electrical & Sensor Calibration
All MGB engines benefit from electrical checks and sensor calibration (OEM 18G722). Engine Finders provides series-level diagnostics to ensure reliable readings, smooth operation, and long-term performance.
Rated 4.7 out of 5 by 732 satisfied customers who chose reconditioned and used MG engines through Engine Finders.
Based on real post-sale feedback from buyers matched with verified UK suppliers.
MG MGB Engines for Sale | Engine Finders
Engine Finders connects UK drivers with specialists for reliable, reconditioned MG MGB replacement engines. Whether battling the thrust washer wear common across 18V B-Series units or oil pressure drops in high-mileage Rover V8 variants, we provide direct OEM-spec solutions for the entire MGB series.
MG MGB Replacement Engines
The MG MGB series evolved through two primary powertrain architectures: the 1.8L B-Series inline-four and the 3.5L Rover V8. Technical evolution moved from the early 3-bearing crankshafts to the more robust 5-bearing 18G/18V designs. A series-wide technical concern involves the "running-on" or dieseling effect addressed in British Leyland service bulletins through the introduction of anti-run-on valves. Shared failure patterns across all B-Series trims include cylinder head bypass hose leaks and premature timing chain tensioner wear. For the MGB GT V8, shared cooling system limitations often lead to localized overheating in the rear cylinders, a flaw inherent to the engine’s positioning within the SJ-style bay. High-mileage units across the series frequently exhibit identical oil pump gear wear, resulting in low pressure at idle. Our reconditioned units address these historical weaknesses through modern machining and superior seal materials.
MG MGB Models & Engines Codes
The MGB series relies on several distinct engine families spanning Roadster and GT variants:
- BMC B-Series 18G/18GA: 1.8L 3-bearing crank – Shared main bearing cap vulnerabilities and oil filtration limitations.
- BMC B-Series 18GD-18V: 1.8L 5-bearing crank – Shared thrust washer failure (Part 12G2111) affecting all manual variants.
- Rover V8 (Low Compression): 3.5L – Camshaft lobe wear and hydraulic lifter ticking common across all GT V8 units.
- 18V North American Spec: 1.8L (1975–1980) – Shared cylinder head cracking due to restrictive "Z-Series" smog manifolds.
All 1.8L engines in the series require verification of the tachometer drive type (mechanical vs electronic) to ensure compatibility with the specific production generation.
Buy Used and Second-Hand MG MGB Engines
For MGB owners, used engines carry high risks due to decades of shared B-Series carbon build-up and thrust washer erosion. We recommend reconditioned units for several reasons:
- B-Series Rebuilds: Include oversized thrust washers (12G2111) to prevent the series-wide crankshaft end-float issue.
- V8 Remanufacturing: Essential for GT models to include high-rev lifters and zinc-rich oil break-in protocols to protect the camshaft.
- Lead-Free Conversion: All our reconditioned heads feature hardened valve seats, essential for modern fuel across the entire MGB series.
Every remanufactured engine ensures that shared engineering flaws, like the fragile oil pressure relief valve springs, have been updated.
MG MGB Engines in Stock
Our reconditioned MGB engines are built to modern tolerances while preserving the classic driving characteristics of the Roadster and GT series:
- Block Machining: Blocks are bored and honed to 0.020" or 0.040" with new pistons to correct series-wide bore glazing.
- Crankshaft Grinding: Journals are polished and matched with heavy-duty shells to eliminate the low-pressure issues typical of the series.
- Component Updates: New timing chains, tensioners, and high-capacity oil pumps are fitted as standard to all 18V families.
All units undergo 4-hour dyno tests simulating Roadster touring and GT load profiles, with compression ratios verified against original Leyland workshop standards.
Warranty for Replacement MG MGB Engines
We provide a 12-month warranty on all rebuilt MGB engines. This coverage covers all 1.8L B-Series and 3.5L V8 engine families within the series.
- Series-Wide Terms: Applies to all Roadster and GT configurations, regardless of the original export market spec.
- Internal Parts: Coverage includes the crankshaft, camshaft, valvetrain, and all lubricated internal components.
- Technical Support: Access to specialists familiar with the specific tuning requirements of SU and Zenith carburetted series.
Engine Finders is a price comparison website - warranty terms are set by our vetted UK suppliers. Final coverage varies by engine family and historical mileage.
Expert Tips for Choosing the Right Engine for Your MG MGB
♻️ MG MGB Engine Types Explained
- Reconditioned Original: Best for the 1798cc B-Series, addressing worn camshafts and oil pressure.
- Exchange Units: Popular for the 18V/18GF 1800cc engine, reusing your core for a rebuilt one.
- Upgraded Rebuilds: Ideal for unleaded conversions with hardened valve seats and modern oils.
- Rover V8 conversions (3.5L/3.9L) are a common "swap-ready" crate engine option.
£ MG MGB Replacement Engine Cost in the UK
- Exchange reconditioned 1798cc B-Series: £1,800 - £2,800.
- Performance rebuild with fast-road cam: £3,500 - £4,500.
- Complete Rover V8 conversion kit (engine & ancillaries): £5,000+.
- Used, running engine from a rusted donor: £600 - £1,200.
🔍 Finding the Right MG MGB Engine
- Check engine number prefix: '18G' for early 3-main bearing, '18V' for later 5-main.
- Identify if your car is pre-1975 (twin SU carbs) or post-1975 (single Zenith-Stromberg).
- Rubber-bumper cars (1975-on) may have different engine mounts and exhaust downpipes.
- Ensure the engine block has the correct oil filter housing (spin-on vs cartridge).
⛽ MG MGB Petrol vs Diesel Engines
- The MGB was never fitted with a factory diesel engine.
- All original engines are carburetted petrol and are ULEZ exempt (pre-1973).
- Rubber-bumper cars (1975-1980) are also ULEZ exempt as classics over 40 years old.
- For modern efficiency, some owners perform diesel swaps (e.g., BMW M47), but this is rare.
🔒 Quality Assurance & Warranty
- Verify unleaded conversion with hardened valve seats (e.g., Colsicoat inserts).
- Ensure oil pressure relief valve and oil pump have been replaced or refurbished.
- A reputable rebuild should come with a 12-month, parts-and-labour warranty.
- Request a dyno sheet or documented oil pressure readings (min 50psi hot).
🛒 Compare & Save on MG MGB Engines
- Provide your old engine as an 'exchange' core to save £400-£600.
- Source a used engine from a reputable MG breaker and have it rebuilt locally.
- Avoid sellers who haven't addressed the B-Series' known camshaft wear issues.
- We can source engines from trusted UK specialists like Moss Europe or Frontline.
⚙️ MG MGB Engine Works: How Experts Rebuild Engines
When your engine fails, MG MGB engine works can restore performance at a fraction of the cost of a brand-new engine. From diagnostics to rebuild, here's how experts ensure optimal results.
1. Classic B-Series Disassembly & Inspection
The engine is stripped, with particular attention to the camshaft and followers for pitting, a classic failure point. The crankshaft is checked for wear on the main and big-end journals. The block is examined for cracks, especially around the core plugs.
2. Machining & Component Upgrading
The block is bored and honed, often to +0.020" or +0.040". Cylinder heads are refurbished with new valve guides and unleaded valve seats installed. The crankshaft is reground and fitted with oversize bearings. The oil pump is rebuilt or replaced.
3. Reassembly with Updated Specs
The engine is rebuilt using a replacement reground camshaft and new followers. The timing chain and tensioner are replaced. Main and big-end bearing clearances are set to the upper end of the factory tolerance for better oil pressure. New core plugs are fitted.
4. Ancillary System Overhaul
The distributor is rebuilt or replaced with electronic ignition. The carburettor(s) are fully rebuilt and tuned. The water pump is replaced. All gaskets are modern composite types. The engine is painted in the correct MGB colour (typically green or black).
5. Dyno Run-In & Tuning
The engine is run on a dyno with break-in oil. Valve clearances are checked and adjusted hot. Ignition timing and carburettor mixture are finely tuned to achieve optimal power and smooth idle. Oil pressure is verified (minimum 50 psi at 3000 rpm hot).
6. Final Testing & Documentation
A compression test is performed (target ~175 psi per cylinder). The engine is leak-tested. A final inspection ensures all fittings are secure. Documentation, including dyno graphs and a parts list, is provided with the engine.