Cosworth EJ25 Forged Piston Set 8.2CR

ENABLING GREATNESS

Cosworth leans on 65 years of motorsport piston development experience to provide a superior design.  We have relied on Cosworth pistons to propel our engines to success for over 20 years.  Their F1-inspired forging design responsible for that success is only now being incorporated in competitor's designs.

Cosworth EJ25 pistons utilize a boxed and bridged forging that greatly reinforces the pin bosses and crown allowing strength and stiffness to be drastically increased while a very short pin length and slipper skirt reduces weight.  Using a proprietary 4032 alloy blend and a piston offset allows their pistons to also offer minimal noise and blow-by while a Xylan skirt coating reduces friction and allows the piston to better conform to the bore. Included high-performance low-tension piston rings, made to the highest standards in Japan, also contribute to reduced blow-by and oil consumption under demanding conditions.  Finally they utilize high tension tangless pin circlips to ensure the clips stay in place even under the most extreme forces.

We highly recommend these pistons for street performance and weekend trackday applications under 600bhp. 

NOTE:  A special tool is required to install the piston pin circlips.

Manufacturer Part Nos 10001430 (99.5mm), 10001431 (99.75mm)

Piston Specs:

• Compression Ratio = 8.2 (8.6 w/ D25 cylinder heads)
• Cylinder Bore Sizes = 99.5mm or 99.75mm
• Piston Alloy = 4032
• Recommended Bore Clearance = .0025 to .0032in
• Piston Pin Wall Thickness = .220in
• Applications = EJ257/EJ255