Minor thrust face

After watching rotating Assembly I heard that sometimes the minor thrust face skirt is reduced to reduce friction. However wouldn’t you want the major trust face skirt reduced ?

Yes, and with some pistons they do that.

However, there are some very high loads applied through the major thrust face, especially with high combustion pressures and/or short rod-stoke ratios. When material is removed from that side the loads on the remaining interface increases and this can cause issues with wear, piston rock and ring seal, even structual failure.

Some very high performance pistons have almost no skirts, but they are VERY carefully designed and have short service lives - Formula 1 is the cutting edge on this, as you can see - [edit] strange, I checked that link worked when making the post.

This should be a direct link to the image I used - http://www.formula1-dictionary.net/Images/engine_piston.jpg