Building a motor isn't difficult, but it certainly calls for a wide range of tools and requires certain knowledge that isn't always evident. Unfortunately, thereare so many components involved when piecing a motor together that most buildup stories tend to be more of an overview rather than a detailed step-by-step process, so you tend to miss the little things.
Take file-fitting piston rings. The main advantage is that it promotes a better combustion seal by setting exact tolerances, which helps to reduce blow-by and, more importantly, prevents the rings from butting up against one another and scoring the cylinder walls. A healthy set of rings is essential to generating power. Without them, there's nothing to hold back the pressure during the compression cycle, and while it isn't hard to figure out, let's just say that you won't be going anywhere anytime in any hurry.
This is not to imply that file-fitting pistons is a requirement, especially considering many aftermarket manufacturers offer complete file-fit ring packages. But it is a good idea to check them for every build, as it'll ensure proper clearances for your particular application. So while your average rebuild certainly doesn't demand it, following this method will ensure maximum performance out of every build. Bear in mind, when we say "maximum," that file-fitting rings won't necessarily translate into increased horsepower; however, by improving the motor's efficiency, you'll be taking full advantage of the power your mill can generate.
We began by cleaning each ring with a paper towel saturated with lacquer thinner. Once the
Next we placed the ring into the bore with a squaring tool and measured the initial end ga
Using a feeler gauge, we measured the current end gap so we'd know how much to take out. I
When grinding the end gap, you only have to do one side. It may take four or five tries, s
After filing them to size, we used a fine file to clean the edges and smooth out the sharp
To place the oil ring, which is a three-piece configuration, we spaced the end gaps approx
Make sure all the rings rotate freely. For the second and top rings, we placed them 180 de
|GENERAL GAP GUIDELINES |
|Ring||Application||Minimum End Gap(Per Inch of Bore) |
|TOP RING |
|(Ductile Iron)||High compression||0.0045 |
|Naturally aspirated drag racing||0.0040 |
|Naturally aspirated street||0.0040 |
|SECOND RING |
|(Ductile Iron)||Naturally aspirated gas||0.0035 |
|OIL RING||Upper and lower rails||0.018-0.060 |
13420 South Normandie Ave.
3402 Democrat Rd.
Federal Mogul (Fel-Pro)