Genuine Mazda Cylinder Head Gasket – 1.8 • BP26-10-271

Genuine Mazda Cylinder Head Gasket – 1.8

Replacement Genuine Mazda cylinder-head gasket for Mazda MX-5 Mk1 NA 1.8 models and early Mk2 NB models fitted with the non-VVT 1.8-litre BP petrol engine.

The cylinder-head gasket is installed between the engine block and cylinder head. It seals each combustion chamber while keeping the engine-oil and coolant passages separated as they pass between the block and head.

A correctly sealing head gasket is essential for maintaining cylinder compression, coolant circulation and engine-oil control. Failure can allow combustion pressure, coolant or oil to pass between systems or escape externally.

One gasket is fitted per engine, and this listing supplies one Genuine Mazda cylinder-head gasket.

Important fitment restriction: BP26-10-271 is for the early non-VVT 1.8-litre BP engine. It is not suitable for 1.6-litre MX-5 engines, later Mk2.5 1.8 VVT engines or factory turbo models.

• Part type: Cylinder-head gasket
• Common names: Head gasket / cylinder-block-to-head gasket
• Mazda catalogue description: Gasket, Cylinder Head
• Installation position: Between the cylinder block and cylinder head
• Function: Seals combustion chambers, oil passages and coolant passages
• Engine application: Early non-VVT 1.8-litre BP petrol engine
• Primary MX-5 engine applications: BP-ZE / BP-4W
• Quantity fitted per engine: 1
• Quantity supplied: 1 gasket
• Cylinder-head bolts included: No
• Cylinder-head bolt washers included: No
• Camshaft-cover gasket included: No
• Inlet or exhaust manifold gaskets included: No
• Valve-stem seals included: No
• Sealant included: No
• Brand: Genuine Mazda
• Part No.: BP26-10-271
• MX-5 fitment: Mk1 NA 1.8 and early Mk2 NB 1.8 models through approximately 2000

Typical reasons for replacement:

• Cylinder head removed for engine repair or refurbishment
• Engine overheating followed by gasket failure
• Loss of coolant without a visible external leak
• Coolant contamination in the engine oil
• Engine oil entering the cooling system
• Combustion gases entering the cooling system
• Persistent cooling-system pressurisation
• Low or uneven cylinder compression
• External oil or coolant leakage at the block-to-head joint
• White exhaust vapour associated with internal coolant leakage

Fitment advice: Confirm that the engine is the early non-VVT 1.8-litre BP type. Later Mk2.5 VVT and factory turbo engines use different cylinder-head gasket specifications.

Replacement advice: A cylinder-head gasket must not be reused after the cylinder head has been removed. The cause of the original failure should be identified and corrected before the engine is reassembled.

Cylinder-head inspection: Check the cylinder head for distortion, cracking, corrosion and surface damage. Where overheating has occurred, specialist pressure testing and surface measurement are strongly recommended.

Engine-block inspection: Carefully inspect and clean the block deck without scratching or gouging the sealing surface. Old gasket material, corrosion or raised damage can prevent the replacement gasket from sealing correctly.

Fastener advice: Inspect the cylinder-head bolts, washers and threaded holes. Follow the applicable Mazda workshop procedure regarding bolt reuse, tightening sequence and staged tightening.

Cooling-system advice: Determine why the engine overheated or lost coolant before reassembly. Inspect the radiator, thermostat, cooling fans, water pump, hoses, expansion tank and pressure cap as applicable.

Other items to consider: Consider replacing the camshaft-cover gasket, inlet and exhaust manifold gaskets, valve-stem seals, timing-belt components, water pump, thermostat and associated coolant hoses while the cylinder head is removed.

Useful tools / consumables: Socket set, calibrated torque wrench, angle gauge where required, straight edge, feeler gauges, plastic gasket-removal tools, thread-cleaning equipment, suitable parts cleaner, fresh engine oil, oil filter and coolant.

Difficulty guide: DIY Difficulty: Advanced. Replacement requires substantial engine dismantling, accurate inspection of the sealing surfaces and strict adherence to the Mazda tightening sequence and workshop procedure.

Why Genuine Mazda? Genuine Mazda cylinder-head gaskets match the original combustion openings, coolant passages, oil passages and sealing profile for the applicable BP engine. Correct alignment and construction are essential for maintaining combustion sealing and fluid separation.

What’s in the box: One Genuine Mazda 1.8-litre cylinder-head gasket, part number BP26-10-271.

Installation notes: Drain the engine oil and coolant and remove the cylinder head following the applicable Mazda workshop procedure. Clean and inspect the cylinder-head and block mating surfaces, checking both for distortion or damage. Position the new gasket in the correct orientation over the locating dowels without applying general-purpose sealant. Refit the cylinder head and tighten the fasteners in the specified sequence and stages. Reassemble the engine, refill all fluids, bleed the cooling system and check for compression, oil, coolant or combustion-gas leakage.