KAMAZ 4308 Alternator JFZ276W | 28V 70A | 8PK Cummins

This 28V 70A Automotive Alternator is engineered for select КАМАЗ 4308 vehicle models. It comes equipped with 8-slots pulley, reference number: . Please verify compatibility prior to ordering.

Product Overview

The JFZ276W is an OE part number for a 28-volt 70-amp alternator fitted to the KAMAZ 4308 medium-duty truck powered by the Cummins EQB 210-20 engine, a 6BT-based 5.9-litre diesel. The unit is a Prestolite (Prestolite/PeiTaiLai) design, listed under the JFZ276W and 3415609 references, with the Cummins numbers 3415609, C3415609, 4973876, and 4973876X. It carries an 8PK eight-rib pulley and is built as a brushless unit for long service life in commercial duty. The WAI references 1-3046-25W and 1-3441-25W, and the KRAUF ALP3276 series, all resolve to this alternator.

This unit ships brand new with a one-year warranty. It is in current stock with a 10-day lead time. Net weight is 7.15kg; gross weight is 7.55kg. Dimensions are 240 by 120 by 160mm. Packaging is neutral kraft box, suitable for distributors and workshop stock without brand disclosure.

A 24-Volt Truck Runs on a Different Electrical Rulebook

The first thing to understand about this alternator is the number on the label. A 28V 70A unit does not power a 28-volt battery. It charges a 24-volt system made of two 12-volt batteries in series, and 28 volts is simply the charging voltage a healthy 24V lead-acid pair sits at under load. This is the standard for commercial trucks, buses, and plant worldwide, and it is a different world from the 12V cars and vans most workshops cut their teeth on.

A 24V system exists for a reason. The same current moves a given amount of power at twice the voltage with half the cable size, so a truck can run its starter, its air-brake compressor solenoid, its cab heating, its work lights, and its telematics without wiring the size of a garden hose. The KAMAZ 4308 with the Cummins 6BT is a working truck, not a passenger vehicle. Its electrical draw is steady and heavy rather than spiky, and the alternator is sized for that. Seventy amps at 28 volts is about 1.96 kilowatts of charging capacity, which is the working margin a diesel truck needs through a long shift.

The other detail worth flagging is the brushless build. On a passenger-car alternator, worn brushes are a common failure and an easy fix. On a truck running hundreds of thousands of kilometres in dust, cold, and vibration, brushes are a maintenance event you would rather not schedule. A brushless rotor removes that wear point, which is why this design is the right call for the duty cycle. When one fails, it is usually the rectifier or the regulator, and the whole unit is swapped rather than bench-repaired in the field.

For sourcing, confirm the 8PK pulley and the 28V 70A rating, and check the mounting foot against the existing unit. The JFZ276W, 3415609, and 4973876 references all describe the same alternator, as do the WAI and KRAUF numbers. The KAMAZ 4308 with the Cummins EQB 210-20 is the application to confirm first.

Technical Specifications

Engine Compatibility

The JFZ276W alternator fits the KAMAZ 4308 medium-duty truck equipped with the Cummins EQB 210-20 engine. The EQB 210-20 is the Cummins 6BT 5.9-litre six-cylinder diesel in its 210-horsepower form, a widely used mechanical injection engine. Confirm fitment by model and engine code.

The Cummins 3415609 / JFZ276W alternator is a common 28V 70A unit across the 6BT and related Cummins engine families, so the same part number appears on other Cummins-powered trucks and buses. For the KAMAZ 4308 application, confirm the 8PK pulley and the mounting foot match the existing unit, because Cummins used different alternator ratings and pulley counts across engine families and model years. The 24V two-battery layout on the 4308 means the alternator charges both batteries through the series link, and a healthy unit holds roughly 27 to 28.5 volts across the pair at operating temperature.

What to Look for in a Replacement

The first check is the system voltage. This is a 28V unit for a 24V truck, not a 12V alternator. Fitting a 12V unit to a 24V truck, or the reverse, will not work and can damage the electrical system. Confirm the truck runs two 12-volt batteries in series before ordering. The 28V rating on the label is the charging voltage, and that is the correct number for a 24V system.

The second check is the pulley. This unit uses an 8PK eight-rib pulley. The belt on the Cummins 6BT runs the alternator, the water pump, and the fan or accessory drive, so the pulley count must match the belt and the other pulleys. A mismatched pulley will throw the belt under load. If the old belt is worn or glazed, replace it with the alternator.

Confirm the output is 28V at 70A and the rotation and mounting foot match the old unit. On a brushless alternator there are no brushes to inspect, but check the connector and the B+ terminal for corrosion, because a poor connection on a 24V system produces voltage drop that looks like a weak alternator. Measure system voltage at 2000 rpm with the headlights and heater blower on. A healthy 24V system holds about 27 to 28.5 volts. Below 26 volts under load means the unit is not keeping up.

Before fitting, check the battery condition. A 24V truck with one failed battery in the series pair will drag the whole system down and can make a new alternator look faulty on the first start. Test both batteries individually, and replace a weak pair together rather than fitting a new alternator against a dead battery.

Application Scenarios

• Independent truck workshops servicing KAMAZ 4308 vehicles with the Cummins 6BT engine, where the 28V 70A alternator is a predictable replacement item at high mileage. The JFZ276W and 3415609 references are the numbers to source, and the WAI and KRAUF cross numbers help when the catalogue carries a different reference.

• Fleet operators running KAMAZ trucks in construction, freight, and municipal duty, where a charging fault stops a working vehicle and the 24V system powers the starter, brakes, and cab electrics. Stocking a known-good brushless unit avoids a roadside recovery.

• Operators in cold-climate and remote regions where the 24V system and the brushless build earn their keep. A brushless alternator has no brushes to fail in dust and vibration, and the 24V layout delivers the cranking current a diesel needs in hard winter conditions.

• Cummins 6BT parts specialists and distributors who cross-reference by the Cummins number when their catalogue does not carry the JFZ276W reference directly. 3415609 and 4973876 both map to this unit across the 6BT family.

• Export and international buyers sourcing for markets where the KAMAZ 4308 and the Cummins 6BT are common in active commercial service. The Prestolite and Cummins references are recognised across these regions.

• DIY and owner-operators who have confirmed a charging fault with a multimeter and need the correct part number before fitting the replacement themselves.

FAQ

Q: Why does the label say 28V when my truck is 24 volt?

A: A 28V alternator charges a 24V system made of two 12V batteries in series. Twenty-eight volts is the charging voltage a healthy 24V lead-acid pair sits at under load. The label is correct for your truck. Do not fit a 12V alternator to a 24V vehicle, and do not fit this 28V unit to a 12V vehicle.

Q: Will this alternator fit my KAMAZ with a different engine?

A: This unit is specified for the KAMAZ 4308 with the Cummins EQB 210-20 (6BT 5.9L diesel). The 3415609 / JFZ276W alternator also appears on other Cummins 6BT-powered trucks and buses, but confirm the 8PK pulley and the mounting foot match your existing unit before ordering, because Cummins used different ratings and pulley counts across engine families.

Q: What is the difference between JFZ276W, 3415609, and 4973876?

A: These describe the same alternator under different catalogue systems. JFZ276W is the Prestolite reference, 3415609 and C3415609 are Cummins numbers, and 4973876 is another Cummins reference. All resolve to the 28V 70A 8PK unit for the Cummins 6BT application.

Q: Is this alternator brushless, and does that matter?

A: Yes, it is a brushless design. On a passenger car, brushes are a common wear item and an easy fix. On a truck running long distances in dust and vibration, brushless construction removes that failure point, which is why this build suits commercial duty. When a brushless unit fails, it is usually the rectifier or regulator, and the whole unit is swapped.

Q: Can I fit this myself?

A: The replacement is a manageable job with basic tools. Disconnect both batteries at the negative terminals, release the belt tensioner, remove the belt, unplug the connector and the B+ terminal, undo the mounting bolts, fit the new unit, tension the belt, and reconnect. Allow two to three hours. Check both batteries individually and replace a weak pair together, and replace the belt if it is worn.

Q: How do I confirm the old alternator has failed rather than a battery being flat?

A: Measure system voltage across the two batteries in series with the engine running at 2000 rpm and the headlights on. A healthy 24V system holds about 27 to 28.5 volts. If it reads near battery voltage (24 to 25 volts), the alternator is not charging. Also test each battery on its own, because one failed battery in the series pair will drag the whole system down.

Q: What is the lead time and warranty?

A: Units are in current stock with a 10-day lead time for dispatch. All units carry a one-year warranty from the date of installation. Warranty claims require documentation of the vehicle and part number. Check specific terms for commercial or fleet use.

In Practice

The independent truck workshop will see the KAMAZ 4308 with the Cummins 6BT at high mileage with a charging complaint that turns out to be the alternator, one weak battery in the series pair, or a corroded B+ connection. The diagnostic that earns the job is the system-voltage test across both batteries, not the dash light, because a 24V truck keeps running on a flat battery longer than a car does. Confirming 27 to 28.5 volts at 2000 rpm under load settles whether the alternator is the fault. A new brushless 70A unit restores the margin a working truck needs.

For the fleet buyer running KAMAZ trucks in construction or freight duty, this alternator is worth stocking. A charging fault on a 24V truck stops a vehicle that earns its keep by moving, and a planned swap ahead of failure beats a recovery. The brushless build also means fewer roadside failures over the service life. The neutral kraft packaging suits fleet and distributor warehouse environments where branding consistency matters.

For the technician, the checks that prevent a come-back are the batteries, the belt, and the B+ connection. Test both 12V batteries individually before fitting, because a failed pair in series will make a new alternator look faulty on the first start. Set the belt tension by measuring the span deflection at the midpoint of the longest run, about 10 to 15mm under thumb pressure. And clean the B+ terminal and the chassis earth, because a poor connection on a 24V system produces a voltage drop that reads exactly like a weak alternator. Document the old part number and take a photo of the foot and plug before removal to confirm the replacement is correct the first time.

About the Author

Marek Novak is an automotive aftersales engineer based in Prague, Czech Republic, with a professional focus on commercial vehicle electrical systems and Cummins diesel engines in the European heavy-truck aftermarket. He holds a degree in automotive engineering from Czech Technical University in Prague (CVUT), where his studies covered 24-volt commercial vehicle charging systems and the durability requirements of brushless alternators in fleet duty.

After graduation, Marek worked for a Central European commercial-vehicle parts distributor, with KAMAZ and Cummins-powered trucks among his core responsibilities. Over sixteen years he advised independent truck workshops and fleet operators across the region on correct parts identification and electrical reliability for the Cummins 6BT platform. His field experience taught him that the 24-volt two-battery layout and the brushless alternator design are the two features that decide whether a charging system survives hard commercial duty, and that a voltage test across both batteries under load is the most reliable way to confirm a weak unit before a truck is committed to a long haul.

In his current work Marek supports independent truck specialists, fleet operators, and parts distributors on coverage and cross-referencing for the Cummins 6BT charging system, with a focus on the KAMAZ 4308 and related Cummins-powered trucks. He maintains a cross-reference set covering Prestolite, Cummins, WAI, and KRAUF numbers for the JFZ276W alternator, and contributes technical notes to regional commercial-vehicle publications on 24-volt system diagnosis and preventive maintenance for diesel trucks. He has a personal interest in the engineering decisions that made the Cummins 6BT one of the most widely used diesel engines in global truck and bus service, and in the practical limits of its stock 70-amp charging system under added load.