This complete set of four +0.040in high-compression pistons is made for Austin Healey 100 BN1 and BN2 engines being rebuilt to the 8.6:1 piston specification of this 100M replacement range. Supplied with piston rings, gudgeon pins and circlips, it is intended for cylinders machined to suit +0.040in oversize pistons.
This version provides the high-compression piston specification where an Austin Healey 100 engine requires a +0.040in rebore. It allows the higher-compression engine specification to be retained while using pistons sized for the newly machined cylinders.
The complete set covers all four cylinders and includes the associated rings, gudgeon pins and circlips.
The +0.040in designation refers to the piston diameter relative to standard size. The cylinders should be machined to suit the actual replacement pistons and the required piston-to-bore clearance rather than relying on the nominal oversize alone.
Check the existing bore dimensions and required machining before ordering. Select this size only where +0.040in pistons are appropriate for the engine being rebuilt.
A piston ring compressor is available separately to hold the piston rings in their grooves while the piston is installed into the cylinder bore.
8.6:1 HIGH COMPRESSION
