Nippondenso Type IIF Starter By Scott Fureman The Nippondenso type IIF starter is a heavy duty straight drive starter designed for mid-range diesel, large gas and large diesel applications. This series of starters is available in power ranges from 4.0 to 8.0 kw (kilowatts) at 12 or 24 volts, depending on the exact appli- cation. Like all heavy duty starters, the “2F” is sealed against external moisture with o-rings, and internally against oil (for wet clutch applications) with seals. These starters can be found sharing applications with Delco starters in the 37 through 42MT series. The 2F starter is basic in design for a non-gear reduction unit, although Nippondenso has found some unique, if not more effective ways of doing some things. While most heavy duty units use brass, sintered bronze or oillite bush- ings, the 2F starters use needle bearings on the drive and commutator end frames to maintain alignment and reduce rota- tional resistance. The center support utilizes a conventional bushing. This is possible because the center support sim- ply protects the armature from flexing under load. With the needle bearings supporting the majority of the load and alignment there is very little load placed on this bushing surface. While most heavy duty starters utilize ratcheting drive mechanisms, Nippondenso has chosen to retain a roller clutch in these units. The clutch housing is much wider than normal and houses two stacked sets of rollers, thus creating a ten roller drive. The drive slides along a helical spliced shaft for smooth engagement with the ring gear. The armature shaft will appear to have two sets of salines. The “driving” salines are the salines on which the starting torque is transferred to the drive and pinion. The second “saline” is cut into the armature shaft in the area the pinion resides at rest. Since a major cause of drive failures is misalignment caused by worn pinion bushings, this cut saline helps reduce wear by reduc- ing surface area contacting the speeding pinion as well as retaining a certain amount of lubrication. With the exception of the second helical cut on the armature shaft, the 2F armature is fairly typical and testing and reclamation is straightforward. The commutator and drive end shafts should only be wiped clean or lightly polished with fine emery. Remember, the shaft at these points serves as the inside race for the bearings. The solenoid switch used on these models work in conjunction with the shunt coil in the field case to engage and disengage the pinion and ring gear. The hold in coil is connected to the shunt coil in the field case and a balance test of the solenoid coil alone will indicate a bad switch. Balance testing of the sole- noid coils must include the shunt coil for accurate results. The solenoid switch is operated by a typical start switch, which in turn oper- ates a start relay. This relay sometimes incorporates overcrank protection in the form of the bi-metal strip bolted to the solenoid and a circuit breaker in the relay. Unlike Delco’s OCP system, once the bi-metal opens the relay’s ground circuit the relay cannot be re-energized until the start switch circuit is turned off. In the event the solenoid should be con- tinuously energized the bi-metal will open before the solenoid coil begins to burn. When testing the circuit breaker, energize the coil by connecting a 12 volt source between the blue wires and measuring the resistance between the black wires. The resistance at this point should be 0 ohms. The resistance between the blue wires (the relay coil) should be approximately 4.7 ohms. Assembly is the reverse of disassem- bly. Care should be taken to attach the shunt coil to the correct brush terminal. Also, the brushes should be installed so that the lead wire with the tube is clos- est to the field frame. This wire is then twisted so that the tube is toward the outside and protects the lead from short- ing to the commutator end cap. Although Nippondenso designed the 2F starters to operate up to 30,000 crankings without maintenance, we live in the real world. The 2F starter’s popularity among OE manufacturers provides an excellent opportunity for the rebuilder who is willing to face the challenges the OEMs provide and set himself apart from the “fix-it” stereo- type our industry has faced in the past. Scott Fureman, Purfex Electrical Distributors, Spring City, PA.