Let’s be honest here, one of the points in engine assembly where you have a higher risk of breaking something is when you’re fitting the pistons and rings into the bore. The process of compressing your piston rings with a ring compressor and then sliding the compressed assembly into the bore requires a lot of things to go right in order to work properly.
A one-piece — or “fixed bore” — ring compressor, like the ones from Total Seal, makes inserting the piston and rings into the bore easy and straightforward, even if you’re running thin, competition-style rings. By being built to the exact bore size of your engine, there is nothing to get wrong and no real chance of damaging your rings (as long as you aren’t actively trying to break something).
Made from a solid piece of aluminum in Total Seal’s Phoenix, Arizona factory, the one-piece ring compressors are first machined with a stellar bore surface finish, and then anodized for longevity of that finish. The tool’s cylinder walls are machined with a standard 5-degree taper to easily compress even the beefiest of rings with a minimum of effort.
Optionally, if you are using the one-piece ring compressor on rings with a narrow radial thickness — less than .125 inch — Total Seal manufactures a version with reduced wall taper to account for the reduced tension of the ring, and provide a smoother transition into the cylinder bore. We’ve even seen them modified for use (with the thinnest rings we’ve ever personally seen) by machining finger notches in the sides of the tool.
Using A One-Piece Ring Compressor
The beauty of the tool is in the simplicity of its use. After lubing up the walls of the tool and the piston rings and skirt, you simply feed the rod through the hole and fit the compressor ring around the base of the piston skirt. You then ensure all the rings are lined up properly, slip the compressor up around the ring pack, and then use the protruding skirt to align the whole assembly with the cylinder bore and seat the assembly on the deck. Then, you simply tap the piston into the bore. Nothing to assemble, nothing to disassemble.
With no parts to break, you’ll probably only have to buy a given bore size once in your lifetime. If you’re building enough engines to wear one out, you’ll probably appreciate the simplicity and ease of use of the one-piece design even more. However, there’s a reason we currently have multiple bore sizes in the toolbox (they even have our uncommon custom LS engine bore size available).