How to install pistons on rods

Place your rings on a numbered piece of clean cardboard as a simple method of keeping track of which rings are destined for which cylinder. First and foremost, read the directions included by your piston ring manufacturer. This piston ring manufacturer has color-coded the ends of the oil control ring expander in an effort to prevent overlap during installation.

Once the expander has been installed, the oil control rings go on. This process is then repeated with the lower ring. With the oil control rings in place, double-check to make sure the expander ends are still correctly butted together and not overlapped. Then position the oil rings so that their respective end gaps are on opposite sides of the wrist pin. Next comes the second ring.

First ascertain that the ring is properly oriented the dot on the ring faces up , and then use a piston ring expanding tool to install the ring into its groove on the piston.

The top ring is installed in the same fashion as the second ring. Normally the end gaps are placed degrees apart. Having sufficient lubrication to the wrist pins during initial start up is important. Use either a good coating of motor oil or assembly lube. Apply a thin coat of oil to the piston rings and skirts to ease installation into the bore and protect them during initial startup. Position the crankshaft so the journal of the cylinder in which you intend to install the piston is in the proper location to accept the connection rod without interference.

Install the upper half of the rod bearing insert in the connecting rod and the lower portion in the corresponding connecting rod cap. Apply a coat of motor oil or assembly lube to the bearings.

After double-checking the ring end gap orientation, install a piston ring compressor on the piston and the protective sleeves onto the connecting rod bolts. Check rod and piston number and orientation to the cylinder in which they are being installed. Here we start with the number-1 cylinder and rod noting that the thick side of the connecting rod marked with a dot of yellow paint during assembly is faced toward the crankshaft counterweight to the outside and the number stamped on the rod is faced to the outside.

Keith Black supplies a piston orientation diagram with their products. Once the piston and rod assembly has been properly aligned, slide it into the bore until the ring compressor contacts the deck surface. Whatever you do not pound on the piston this mat break a ring or damage the crankshaft if the connecting rod hits it. On style A there is no mark and you can place the piston in either direction so that the connecting rod lines up with the crankshaft.

Then follow the instructions for the C and D style pistons. In this step I seperated the crank webs from the pin. I put the crankshaft into the press while using a vaiety of press pins to push the pin through the first crank web.

When the pin was almost fully out I held the crankshaft so it would not fall on the graound. The pistons need to be rid of any dust or dirt before you place them on the connecting rod. If you are not using new pistons, then make sure they are squeaky clean. For the best experience on our site, be sure to turn on Javascript in your browser.

There are many ways to adhere the piston to the connecting rod and each have unique pros and cons. Here's a look at different piston lock types and how to correctly install them. Ask experienced engine builders to identify the most frustrating or aggravating step in the assembly process, and the likely consensus will be installing any style of those temperamental spring-loaded wrist-pin locks.

If they fail, then any number of scenarios can follow, almost all of them catastrophic. To swear that these gruesome instruments of torture are cursed is not a sin.

Yet, we must understand them to love them. There are three methods of attaching a piston to a connecting rod:. The press-fit semi-floating pin is prevalent in production engines, especially older models, while most high-performance engines use full-floating pistons.

Also, floating pins are naturally centered in the piston, which assures even loading. On the downside, free-floating pistons require those nasty locks. But hardly any solution is achieved without some complication. The majority opinion about wrist-pin locks is that they solve more problems than they create. But what about pin buttons?

Buttons are also heavier. Pin buttons have also earned a sour reputation for wiping oil off the cylinder wall and possibly scoring the metal surface—or at least scraping the oil in that location and allowing grit or carbon buildup to dig into the wall. These are spring-type fasteners designed to provide an interference fit in a groove machined at the edge of each pin boss. The locks keep the wrist pin centered within the pin bosses while allowing for rotation. The elasticity of the lock allows them to be deformed in some manner for installation and removal.

There are three types used in automotive engines—snap ring or Tru Arc; Spirolock; and the wire lock or circlip, which is offered in at least three different designs. The last two styles are the most popular with performance engine builders.

Generally Tru Arcs are the easiest to install and are more popular in lighter duty applications. The snap ring or Tru Arc is easily installed using dedicated pliers. The tips of these pliers fit into the holes at the ends of the snap ring. When the pliers handles are squeezed, the snap ring compresses enough to firmly seat into the retaining groove on the piston.

A word of caution: snap rings are manufactured with a smooth and rough side. Be sure the smooth side faces the wrist pin. The Spirolocks—sometimes referred to simply as a spiral retaining ring—are constructed of flat stainless-steel wire wound into a spiral or small coil.

Many pistons require two Spirolocks on each side, doubling the installation time. There are probably as many different ways to install Spirolocks as there are engine builders. There are also some dedicated spirolock tools. A Spirolock is installed by spreading it apart slightly.