Piston Expanders?

[DD931]

Back in the day, piston expanders were common. Various approaches. I remember ones that were made of spring steel and worked on the piston pin bosses to encourage that part of the piston to expand. Had to be installed with special pliers to get them properly in position. Seems to me I used them on the flathead six in the family '48 Dodge. Might have bought them from Montgomery Ward.