Wiseco K554M785 Forged Piston Kit for 1990-1993 Mazda Miata / 78.5 mm Bore

Vehicle Fitment

• 1990-1993 Mazda Miata (B6 / 1.6 L, turbo or naturally aspirated)
• Mazda 323 / Protege (1.6 L B6 series, 78.5 mm bore)

Features

• Forged from 2618 aluminum for high strength and durability
• ArmorGlide® skirt coating to reduce friction and noise
• -13.0 cc dished crown (turbo-friendly) for lowered compression
• Fully machined crown with four-valve reliefs
• Precision ring grooves for superior sealing
• Press-fit or floating 20 mm wrist pin options
• High-performance ring set (7850XX) included
• Designed to handle forced induction and high RPM usage

Specifications

• Bore: 78.50 mm
• Stroke: 83.50 mm
• Compression Height: 31.95 mm
• Piston Volume (Dish): -13.0 cc
• Compression Ratio: ~8.6:1
• Wrist Pin Diameter: 20 mm
• Ring Set: 7850XX (1.0 / 1.2 / 2.8 mm)
• Piston Weight: ~275 g
• Set Quantity: 4 pistons

Included Components

• 4x forged pistons
• 4x wrist pins (20 mm)
• 4x 7850XX piston ring sets
• 4x circlips / locking rings

Product Description

The Wiseco K554M785 piston kit is a performance-focused, forged set designed for Mazda's 1.6 L B6-series engines, particularly in early Miata (1990-1993) and 323 / Protege models. Made from 2618 aluminum, these pistons are built to withstand boost or high-stress high-RPM applications.

With a -13 cc dished crown, the compression ratio is tuned to around 8.6:1, making this kit well-suited for turbocharged setups. The ArmorGlide® coating on the skirts helps reduce friction and wear, while the precision ring grooves and included 7850XX ring set provide excellent sealing under load.

The kit includes all the necessary hardware - pistons, 20 mm wrist pins, circlips, and ring sets - providing everything needed for a full engine build. Whether you're building a street turbo Miata or a high-performance compact engine, the K554M785 delivers strength and reliability for aggressive tuning.