CHRIS-MARINE®

Unistress Piston Ring Expander / UPRE

For 4-stroke engines with straight-cut piston rings.

  • Lowest stress possible for a desired opening of the ring
  • Provided with a stop, limiting deformation of the ring
  • Delivered adjusted and ready for use
  • Suits any type of piston ring and diameter upward of 130 mm
  • Type 1: piston rings 100–250 mm
  • Type 2: piston rings 250–380 mm
  • Type 3: piston rings 380–600 mm
  • Type 4: piston rings 600–980 mm

Unistress Piston Ring Expander - UPRE

Unistress Piston Ring Expander - UPRE

Unistress Piston Ring Expander - UPRE

The figure shows the stress distribution in a ring opened with a UPRE Unistress Piston Ring Expander.

The figure shows the stress distribution in a ring opened with a UPRE Unistress Piston Ring Expander.

Four different types available.

Four different types available.

To open straight-cut piston rings easier

Our unistress piston ring expander UPRE is a tool designed to open straight-cut piston rings on 4-stroke engines. Each type of UPRE has been provided with a stop. The stop limits the deformation of the piston ring to a minimum, still allowing the piston ring to slip over piston diameter.

UPRE  – different sizes

  • Type 1, piston rings 100-250 mm
  • Type 2, piston rings 250-380 mm
  • Type 3, piston rings 380-600 mm
  • Type 4, piston rings 600-980 mm

Often bought together with