He also added that you need be sure it is rigid and durable. Look for quality welded joints and heavy gauge metal. Remember, a shop press is as important an investment in your business as any of the other shop machines you use. Goodson offers several units for piston pin pressing and for pressing pin bushings, particularly tapered pin bushings. This fixture is composed of several parts that combine to take some of the guess-work out of removing and installing interference fit piston pins.
It was designed to protect high dollar pistons from damage since the piston itself is NEVER under pressure. One of the key features is a series of support inserts that you use to keep the connecting rod aligned properly.
Several standard sizes are available, plus one that is ready to be machined to your exact needs. For a complete run down on how to use the Piston Pin Removal and Installation Fixture, check out the product instructions. One last warning that applies with all of these operations: If you run into excessive resistance, do NOT keep applying pressure. 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. Post by crazycuda » Sat Sep 02, pm I have used both the press on method and heated them as usual pushed the pin in.. From what I was told by the local GM dlr, the rods should have the pins pressed back in, do not heat the rods. Sorry if I ask alot of questions, but you never stop learning if you ask questions. Post by machine shop tom » Sat Sep 02, pm I am seeing more of the powdered metal rods in my shop.
Up to this point, we have been hanging the pistons using a propane torch to heat the small end. We have had no comebacks with the powdered rods, but that isn't to say that it is the proper method or that there haven't been problems that we are unaware of.
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