There aren't always marks that will show you which way is which. Most, if not all, of the cheap piston manufactures (The ones from over seas) don't put these marks on their pistons. The "Made in U.S.A." Products will usually have a dot right on top of the piston. I've even seen arrows used to indicate this.
If you can't locate any marks, then contact whoever you purchased the pistons from and ask them.
Thursday, January 7th, 2010 AT 10:06 AM