Toyota 1HZ and 1HD diesel swaps in Land Cruisers

Why people do it

Torque, sound and loyalty. The 1HZ makes 129 hp and 210 lb-ft from 4.2 litres with no turbo. The 12-valve 1HD-T, which went into the HDJ80 from 1990, makes 164 hp and 266 lb-ft at 1,400 rpm. The 24-valve 1HD-FT arrived in the HDJ80 in 1995 with 168 hp and 280 lb-ft. Those aren't huge numbers. What owners want is the low-rev pull, and it's Toyota-built.

There's a practical case too. Gearboxes, bellhousings, starters and clutches come from Toyota's own parts bins, and Toyota mechanics know the engines. Don't do it for fuel economy alone. One 80 Series owner went from about 200 to about 300 miles a tank around town, but another forum member reckoned the real gain over the petrol 80 was only 1–2 mpg.

What it takes

First, match the gearbox. The H55F five-speed is the usual partner in 40s and 60s, but only the version that came behind the 1HZ in the 70 Series has the right bellhousing and input. A 1HD-T's 300 mm clutch disc is 14-spline and the H55F input is 21-spline, so builders either use the 275 mm 1HZ clutch (some say it's marginal behind a turbo) or adapt a 300 mm disc from another make. In an 80, the H151 suits the 1HD and the H150 was used only behind the 1HZ.

Second, mounting and cooling. In a 40 or 60 you'll be fabricating or buying frame brackets and a crossmember, then checking driveshaft angles and fan-to-radiator alignment. In an 80 the factory diesel mount points are already there. Third, electrics. The 1HZ and 1HD-T are mechanical and easy to wire. The 1HD-FTE has its own ECU, a drive-by-wire pedal and a spill valve, so buy a whole donor or a complete harness. The diesel starters are usually 24-volt, and the tach needs a signal from the injection pump or a diesel cluster.

Finally, refresh the engine before it goes in. Build threads routinely do the timing belt, water pump, rear main seal and clutch while the engine is out, and one builder found badly worn bearings on a used 1HZ.

Parts and kits

Nobody in the US sells a boxed 1HZ-into-FJ40 kit with an instruction manual. Most of the parts are genuine Toyota pieces from diesel 70 and 80 Series trucks, bought through dealers or Australian specialists. Builders add frame brackets and crossmembers they've made themselves or bought from forum members. For the 105, Australian shops sell conversion-specific brackets. If you'd rather write a cheque, FJ40 and 80 Series restorers such as Proffitt's Resurrection Land Cruisers have built Toyota-diesel conversions.

Or skip the swap entirely. Factory-diesel 80 Series trucks can be imported once they're 25 years old. Turbodiesel HDJ80s and HDJ81s sold on Bring a Trailer for $14,500 to $75,000 in 2025–26, which is often less than a professionally built conversion.

Emissions and registration

Federally, EPA's engine-switching policy treats a swap as tampering unless the finished vehicle matches a certified configuration of the same or newer model year as the chassis. Toyota never sold these engines in US Land Cruisers, so a US truck has no certified diesel configuration to match.

California is stricter in practice. BAR's Engine Change Guidelines say the installed engine must be the same model year or newer than the vehicle and of the same GVWR class, and its certification must be California or federal, as the vehicle's is, with proof from the manufacturer or a CARB Executive Order. All of the donor's emissions equipment must be fitted, the truck must pass a BAR Referee inspection, and engines that aren't emissions-certified may not go into any emission-controlled vehicle. Gasoline vehicles from 1975 and earlier, and diesels from 1997 and earlier, are exempt from Smog Check. The guidelines don't say how a referee treats a pre-1976 petrol truck that now runs on diesel, so ask the referee before you buy parts. Other states vary widely, so check with your DMV and emissions program first.

What it costs

On forums, a used 1HZ alone cost about $6,500 in 2022, and engine-and-gearbox combinations were $6,000 and up in 2017. One FJ40 builder put his used conversion parts (bellhousing, input shaft, clutch bits, crossmember) at about $1,300–1,400. In 2017, a 1HD-T, an A442F and a non-running 1997 80 Series donor were listed together for $10,000 OBO. A finished 1HD-T 80 Series conversion was advertised in 2011 for $28,900 OBO.

On the sale side, Bring a Trailer results are mixed. A 1HZ HJ60 sold for $20,250 in 2025. A 1HZ FJ40 and a 1HZ BJ40 stalled at $22,500 and $23,250 without selling, and a 1HD-T BJ40 was bid to $69,000 in October 2025 without selling. A swap won't automatically pay for itself.