Same family, different stroke
The 4JA1 and 4JB1 belong to Isuzu's 4J family of four-cylinder diesels. They share the bore; the 4JB1 has a longer stroke, which takes it from about 2.5 litres (4JA1) to about 2.8 litres (4JB1). Both are simple, overhead-valve designs, and the older mechanical-injection versions are why the family is valued in markets where workshops have basic equipment.
The 4JB1 is the one in our catalogue at a published US$ 470 per unit, inside a full container. The 4JA1 and the larger 4HK1 are available as a commercial enquiry: price and availability are confirmed in the quotation.
| 4JA1 | 4JB1 | |
|---|---|---|
| Displacement | About 2.5 L diesel | About 2.8 L diesel |
| Typical vehicles | D-Max and pickups (2.5), light commercial | NKR / NPR light trucks, pickups, Trooper-era 4×4 |
| Other uses | Industrial applications | Generator sets, pumps, light plant |
| Published price (per unit, FOB, full container) | On request | US$ 470 |
| Matching gearbox | On request | Manual, US$ 190 (mixed configurations only) |
Which one your market asks for
The 4JB1 is the workhorse: it powers the NKR-class light truck that carries deliveries, water and building materials across Africa and South Asia, and it has a second life in gensets and pumps. The 4JA1 is asked for mainly by pickup owners and in markets where the 2.5-litre versions were sold new.
Because the two look alike, the engine model has to be matched carefully. Where the engine code or identification plate is visible on the block, it shows in the photos of your order file, so the buyer can confirm the model before paying the balance.
Buying tips
Tell us the application when you enquire — vehicle or generator — because the accessories that matter are different. Plan the container around the 4JB1 volume and add other models to fill it: a 20-ft holds 90 engines, a 40-ft 130, in any mix of the nineteen published models.
Price a container yourself
Build the mix you want in the online quoter — 90 engines in a 20-ft or 130 in a 40-ft, or 45 + 45 / 65 + 65 with gearboxes — and the FOB total reaches your inbox the same minute, at our published per-unit prices, every engine Grade A. Prefer to ask? Tell us the destination country and the models you need and we reply within one business day, usually within hours.
Frequently asked
What is the difference between the 4JA1 and the 4JB1?
Displacement: both are Isuzu 4J four-cylinder diesels with the same bore, but the 4JB1's longer stroke makes it about 2.8 litres against about 2.5 litres for the 4JA1.
Is the 4JB1 used in generators?
Yes. Besides NKR-class trucks and pickups, the 4JB1 is common in generator sets, pumps and light plant.
How much is a used 4JB1?
US$ 470 per unit at our published wholesale price, FOB, inside a full container of 90 (20-ft) or 130 (40-ft) engines.