When building an engine, it's understandable how the sight of all those parts laid across the workbench can be a bit intimidating to most novice engine builders. After having the block freshly machined and the rotating assembly balanced, the biggest challenge left is to assemble it into a smooth running engine. One of the challenges includes installing the piston rings and spiro loxs. Tackling this small procedure doesn't have to be frustrating though. Instead, gaining a few insightful tips from the pros can make the job easier and ensure that your engine is operating at peak form.
So what's the big deal? Installing the piston rings correctly will provide you with a more efficient engine. Conversely, any mistakes here can potentially cause issues down the road such as piston blow-by. Now we're talking an excessive amount of leakage past the rings, loss of cranking compression, loss of power, smoking, and undue oil consumption.
Another important thing to take into consideration is whether your engine is being built for the street or strip, inhale nitrous, feed on alcohol, or run boost; all of which will ultimately dictate the piston ring gap. The good news is that with most off-the-shelf piston and ring assemblies, the hard work involved with pairing the rings to the pistons is generally handled for you. The only thing left to do is assemble the rings onto the pistons.
To get the complete lowdown, we stopped by Quarter Mile Performance in Chatsworth, California, to install a fresh set of Total Seal rings onto a set of LS pistons and showed what it takes to install the spiro lox.
What We Did
Install new rings and lox
Prevent piston blow-by and keep your engine running strong
Just a little sweat equity
|MIN. TOP RING
||OIL RING RAIL
|STREET, STRIP, CIRCLE
||BORE X 0.0065
|Bore x 0.0056
|NITROUS UP TO 150HP
||BORE X 0.007
|Bore x 0.006
|NITROUS OVER 150HP
||BORE X 0.009
|Bore x 0.008
||BORE X .007
| Bore x 0.006
||BORE X 0.008
|Bore x 0.007
||BORE X 0.0085
|Bore x 0.007
The first step when installing...
The first step when installing the rings is to install the spiro lox so the rods can be hung. The spiro lox keeps the wristpin from being squeezed out either side of the piston. Depending on the depth of the groove, the piston may take one or two spiro lox. Our set had a deep groove and required two lox per side. At times, a small flat-head screwdriver can be used to precisely locate the lox into the groove.
Since lubrication protects...
Since lubrication protects against friction, it's critical to oil everything. Michael Consolo smoothed over every point of potential friction area with the tip of his finger. Engine assembly lube or oil will work. We should note that assembly lube sticks better and lasts longer to prevent any galling during initial start up.
Our next step involved positioning...
Our next step involved positioning the tang on the rods. Many engines require different positioning of the tang in reference to the rod and piston. The best part is Chevy engines always face the tang to the outside of the block, or the opposite end of the spring pockets.
With the rod in the correct...
With the rod in the correct position, Consolo slid the wristpin through the piston and installed a set (two lox) on that side.
The oil support rail is then...
The oil support rail is then installed after each ring is cleaned with a solvent; this helps to avoid any contamination. Consolo stressed the fact that the raised "dimple" on the side of the ring must face down. Also, the dimple must go above the wristpin access area. The raised dimple prevents the ring from rotating in the piston groove.
Next is the expander ring,...
Next is the expander ring, also known as the first oil ring. This ring's job is to provide outward tension on the oil rails against the cylinder wall. With the expander ring set, the two thinner rings were placed-one on the bottom and one on the top. Consolo went on to say that you should never face the two ring gaps on top or in line with one another, which would allow excessive amounts of oil to get past or leak by the oil ring.
The second ring that's installed...
The second ring that's installed always has a chamfer or "step" built into its design. Depending on which style ring is chosen for the build, one of these two features will be present. Consolo installed this set of rings and mentioned that the second ring's bevel or chamfer must always face down. In some cases the "raised" dimple will face up to indicate which way the ring needs to be placed.
The top ring or main compression...
The top ring or main compression ring is the final piece to be installed. In the case of the top ring, the bevel goes up along with the dimple. The top ring is the first line of defense in the cylinder against the intake charge, along with heat and pressure from the exhaust gases.
The final step includes positioning...
The final step includes positioning the rings. While final placement varies among engine builders, it's important to understand that the ring gaps must never be lined up prior to installation. Of course, once the engine is fired up and the rings have seated, they will rotate and eventually settle in their own respective patterns.
CHART While ring gaps vary from builder to builder. If you're unsure, you'll be happy to know that Total Seal includes a ring gap sheet that illustrates what gaps to use for a variety of engine combinations.