CHRIS-MARINE®

Piston Ring Expander Unistress / UPRE

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

  • Lowest stress possible for 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
  • The piston ring expander is applicable for a fixed diameter. Price is based on piston ring Ø divided in price categories as indicated below:
    • -Type 1: piston rings 100–250 mm (Price category I)
    • -Type 2: piston rings 250–380 mm (Price category II)
    • -Type 3: piston rings 380–600 mm (Price category III)
    • -Type 4: piston rings 600–980 mm (Price category IIII)
  • Prior to quotation request or placing the PO, please see important information further down the page stating necessary specifications required for further handling.

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.

When placing your order

When placing your order, please provide the following information:

  • Piston diameter (mm)
  • Piston ring:
    • height (mm)
    • width (mm)
    • cut (type C and type D) – see picture below
  • Oil scraper ring;
    • height (mm)
Cut details

Cut details

Often bought together with