Home › Forum › Ask A Member › Wrist pin installation › Reply To: Wrist pin installation
The deal is, the pin is a press fit in one side of the piston and a slip fit in the other side. That allows the aluminum piston to expand and contract without being constrained by the steel wrist pin. The slip fit side is marked LOOSE.
To remove the piston, if you plan to save it, you must support the tight side over a hole (for the pin), and drive the pin down through the tight side. Since the tight side is supported, the driving pressure will not distort the piston.
But I assume you are installing new pistons. Support the tight side and using oil, slide the pin in through the loose side until it meets the tight hole. Then continue driving it home into the tight side. Be careful you don’t go too far, or you will need to drive it all the way through and start over.
Yes, it will help to heat the piston. No need to get it red hot, but about as hot as you can handle is ok.
The book shows use of a cradle, but that isn’t really necessary. I’ve never owned a cradle, but have installed hundreds of pistons.