Production Turbo Piston 3.8 Liter
Casting number 25531260



Features of Note:
  • This is the stock Buick V6 turbo piston part # 25531260. Some sources state that AE (now part of Federal Mogul) made them for GM under the "Hepolite" brand
  • It has the steel insert under the crown which forms the top ring land.
  • It has dual oil drippers from the bottom ring to lubricate the piston pin. There are no drains to the inside of the piston as with other versions of the piston
  • It has a full skirt.
  • It has support under the pin.
  • You can see the cast finish of the piston.
  • This piston has the smoothest moving piston pin of all versions of the piston.
Features of Note:
  • It has a dished top with a cast finish.
  • There are no drain holes drilled from the bottom ring land to the inside of the piston.
  • The light spot in the dish is a small dimple on the same side of the piston as the green dot was on the bottom of the piston. It should show the side to the front during installation.


Features of Note:
  • The full skirt can be seen quite clearly.
  • It has a steel plate supporting the side of the piston around the piston pin.
  • It has an oil hole drilled through the pin holes for lubrication.
  • It has cast support ribs from the pin hole to the piston crown.
  • I believe the green dot is to show the front of the piston for
  • Very often, these pistons will show tiny cracks starting on the top of the pin oiling hole and propagating inward

Submitted by:

David Chase