Cometic MLS Head Gasket 84mm Bore .080in - NA8/NB1 Miata (94-00)

The Cometic C4568-080 is a multi-layer steel (MLS) cylinder head gasket for the Mazda 1.8L BP engine (BP-ZE / BP-4W) with an 84 mm bore and a compressed thickness of .080 in. Cometic lists it for the 1994-1997 Mazda Miata (NA, 1.8L) and the 1999-2000 Mazda Miata (NB1). The stock BP bore is 83 mm, so this gasket is for engines bored 1.0 mm oversize; match the gasket bore to the finished cylinder bore.

• 84 mm round bore, sized for a BP block bored 1.0 mm over the stock 83 mm; Cometic also makes this gasket in C4560 (83 mm) and C4569 (85 mm) bores
• Compressed thickness .080 in, well over the 0.032 in factory 1994-2000 metal gasket; a thicker gasket adds combustion-chamber volume and lowers compression (used for boost or to restore deck clearance after machining); Cometic does not publish a compression ratio for this gasket, so calculate it for your build
• 5-layer MLS (multi-layer stainless steel) construction; Cometic uses five layers on its thicker gaskets
• Outer stainless steel layers carry a .001 in Viton rubber coating; installed dry, without additional sealant (Cometic says extra sealer can hinder sealing)
• Requires smooth, flat and true head and block deck surfaces; Cometic recommends a surface finish of 50 Ra or finer
• Made to order by Cometic; use the head bolt (fastener) manufacturer's torque values

Fitment: 1994-1997 Mazda Miata (NA, 1.8L BP-ZE) and 1999-2000 Mazda Miata (NB1, 1.8L BP-4W), with the cylinders bored to 84 mm. Not for 2001-2005 Miata (NB2, including the 2004-2005 Mazdaspeed): those heads have different coolant passages and Cometic sells separate gaskets for them (C4983 84 mm and C4984 85 mm bore). Not for the 1990-1993 1.6L (B6). If the head and block come from different years, match the gasket to the head.

Part number: Cometic C4568-080

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