Delco 22S] Style Alternator Problems and Solutions By Ace Electric It is generally understood that one of Delco Remy’s original goals in design- ing the 22SI was to deliver a heavy- duty alternator with a 500,000-mile service life. One of the many problems their design engineers had to overcome is how to get that much mileage out of the brushes. To achieve this goal, they incorporated a very long brush and spe- cial spring. While this design works well in the lab, in the real world prema- ture brush failure of the OE design 22SI alternator is a constant problem. There are several probable reasons why the original design failed to meet expectations, despite the best of intentions. Brush Problems * The fit of the brush in the housing is somewhat loose, and the surface finish of the brush is relatively coarse. The unique spring has both a lower pressure and a higher internal friction than typical coil-type brush springs. ¢ The low brush spring pressure combined with the coarse surface finish can reduce the contact of the brush on the slip ring, leading to arcing and heating. * The soft silicone brush spring seal also forces the brush to breath through the brush pinhole, pulling dust, oil, and moisture through the hole, trapping these harmful foreign particulates in the housing. This can result in poor contact, leading to excessive heat, destroying the brush and spring. Many rebuilders have developed a fix to these brush problems by installing the 21SI swing-arm brush holder in place of the original 22SI brush holder. This also necessitates the extra step of drilling a brush pinhole in the SRE housing. A unique and practical coil spring brush holder assembly has been devel- oped for these alternators. The assembly features a longer brush (one and one-quarter inch), longer than the swing arm, shorter than the OE; a stronger coil spring that adequately deals with typical levels of slip ring run-out; and a metal-graphite- lubricant brush material superior to the original graphite-lubricant. While the OE material is intended to wear longer under ideal conditions, it actually tends to fracture when subjected to constant or intense vibration, and tends to film over under adverse environmental conditions. The metal-graphite brush material offered in the brush holder assembly ensures superior performance in these otherwise harmful conditions. From an installation standpoint, the brush holder assembly requires no additional holes to be drilled. The brush pinhole cast utilized the original OE housing that Delco currently supplies. This saves valuable time and money for you. We also recommend leaving out the silicone seals when replacing the brushes. We believe that it does as much, or more, harm than good (see Figure 1). Figure 1 A Note About TIR In addition to the problems with the OE alternator, rebuilders face another little known problem repairing or remanufacturing the 22SI. The Delco Remy specification for slip ring con- centricity for the OE brush is .0005 inch Total Indicator Run-Out (TIR), not the more commonly used 0.003 inch TIR. While Delco may be able to afford the expensive machining centers that offer this additional degree of accuracy, most independent rebuilders cannot. The result is that turning the OE slip ring may actually increase the odds that your rebuilt alternator will fail if you install an OE type brush. The OE brush will not properly track on any slip ring other than an OE. Quick Start Circuit Problems The 22SI design problems are not limited to the brushes and brush holder assembly. The otherwise ingen- ious Quick Start circuit has its own inherent problems. The Quick Start circuit is intended to act in somewhat the same manner as a “self-exciting” voltage regulator. In other words, it activates through the stator and operates through the trio. The Quick Start circuit is always “on.” It looks for low level AC voltage at the stator terminal, sending a pulse to the regulator, tripping an internal transistor to supply almost full battery voltage to the regulator at about 5 amps of current. When the alternator starts, the trio takes over, and the Quick Start circuit “rests” until it is needed again. One of the problems with this concept is that the application of an external charging source can easily cause the circuit to supply current directly to the voltage regulator before the rotor is spinning. In this case, the trio does not take over, as the sup- plied current continues to go through the Quick Start circuit. The good news is that it will not happen for long. The bad news is that it will not last for long because it will blow the Quick Start circuit. Since the original release of the 22SI, Delco has added an