Many engines have become legendary among avid motorists, sometimes for their longevity, sometimes for their performance and sometimes even their character. In the case of Toyota’s 1JZ and 2JZ, these three boxes are unequivocally checked.
So what exactly are we dealing with? Well, the 1JZ and 2JZ both belong to the Toyota JZ engine family which was first seen in production cars in 1990 and effectively replaced the aging M family of passenger car engines.
The first cars with 1JZ engines included the Toyota Crown Athlete, while the 2JZ engine arrived in 1991 in the Toyota Aristo. Other cars with 2JZ engines include the Toyota Crown and Cresta and the Lexus IS 300.
Members of the ZJ family are straight-sixes with a cast-iron block, alloy cylinder head, one or more belt-driven overhead camshafts and four valves per cylinder. All members of the family were designed for rear-wheel-drive applications and were mounted north-south.
The main difference between the 1JZ and 2JZ units is the displacement, but it’s not as simple as it seems. The 1JZ engine has a bore-to-stroke relationship of 86.0mm x 71.5mm respectively.
This gives it a 2.5 liter capacity, while the 2JZ’s 3.0 liter capacity is achieved by using a longer 86.0mm stroke (making the latter engine square; where the bore and race are equal).
But in addition to the longer crankshaft stroke, the 2JZ engine specs also include the fact that it has a taller block and longer connecting rods, so the 1JZ vs 2JZ comparison isn’t as straightforward as some families motors with varying capacities.
The main variations of the JZ theme over the years have been the fitment of Toyota’s Variable Valve Timing (VVTi) system and whether or not the engine in question used turbocharging.
It is also the basis of nomenclature; the 2.5 liter version with variable valve timing is a 1JZ VVTi and a 3.0 liter engine with turbocharger is a 2JZ-GTE.
In its most basic form, the first non-VVTi 1JZ was a non-turbo unit that produced 125kW of power and 235Nm of torque.
The 1JZ turbo soon appeared with twin ceramic turbos, but this proved a bit of a problem for some owners, with the turbos dying early due to oil contamination in the exhaust reaching the turbos.
This remains one of the few relatively common 1JZ twin-turbo problems and it was resolved with the further development of the 1JZ-GTE which was effectively a 1JZ single-turbo and adopted the latest version of VVTi.
Toyota claimed 206 kW of power for this engine, but may have underestimated the true performance as Japanese laws at the time effectively limited production car power to that figure.
The 2JZ started in non-VVTi form, but for MY98 this technology had been added, bringing power up to 169kW in its most powerful non-turbo form. In this case, the engine used Toyota’s sequential fuel injection and coil-on-plug ignition.
The one everyone remembers, of course, is the 2JZ-GTE which was fitted with a pair of sequential turbochargers, an air-to-air intercooler and VVTi.
Under these same Japanese rules, Toyota still claimed the same 206 kW for the engine, but export market brochures told a different story with 239 kW quoted. Even that might have been a little conservative on Toyota’s part.
For this version, the 2JZ pistons were replaced with a dished design to reduce the compression ratio to a more turbo-friendly level and oil jets were added to cool the pistons from below.
A change to the connecting rod specification saw some of the later 2JZ-GTEs criticized for a weaker bottom end, but overall the 2JZ’s reputation for being bulletproof holds up well.
A real howler and designed in part as an answer to Nissan’s equally revered RB26TT straight-six, the 2JZ-GTE has been found in all manner of Toyotas and Lexus including the Aristo, Altezza and, the most famous of all, the JZA80 Supra RZ, a car that has since enjoyed immortality among collectors. In fact, a 2JZ Supra in any form is hot property.
So why are JZ motors so good? It’s a simple answer, really; they are borderline bulletproof. The cast block is part of the secret and allows for plenty of low-end stiffness, which is what you need when giving the thing a massive boost, as those who use an aftermarket 2JZ turbo kit have discovered.
This block material increases the weight of the 2JZ a bit, but most tuners will be happy to trade a few pounds for this bombproof construction. Other details include the closed-deck design of the crankcase and the oil jets for the pistons.
Making 2JZ power loose and safe is also possible because the crankshaft is a forged (rather than cast) item and it rolls in huge bearing journals.
Frankly, it’s almost as if Toyota had tuners in mind when it sketched the JZ engine, and plenty of workshops tinkered with high-output motors with over 520 kW (700 horsepower) on the low end.
The secret is in the engine’s ability to handle boost and although the odd tuner has built a supercharged 2JZ, the vast majority of modifiers stick to turbocharging.
But even details such as the standard 2JZ oil pump, cooling system and timing belt layout will support up to 750 kW (1000 horsepower).
What’s wrong with them? Not many, although the sequential-turbo models we mentioned seem to destroy turbochargers with some ease.
Again, most tuners upgrade to a larger single turbo that can still provide the boost and flow required for big power.
Beyond that, it’s small beer. The timing belt tensioner bracket can fail, the engine can destroy its own crankshaft pulley, and there have been cases of oil pump seals failing.
There are of course alternatives for these things and thanks to the popularity of the engine you can buy a complete 2JZ crate engine as well as a 2JZ alloy cylinder block. Longer stroke crankshafts are also available to increase displacement.
Finding a used 2JZ engine for sale isn’t too difficult, as the unit has found its way into many Toyota and Lexus models.
Specialized importers of used engines are a good place to start. A 1JZ will be cheaper to buy, but even the average 2JZ price seems like good value for such an iconic powertrain.
A 2JZ-GE that did not have a turbocharger can also be found for less, but will need to install low compression pistons before adding boost. Also don’t rule out the engine of a wrecked Lexus IS300 2JZ.
An imported 1JZ Soarer is another option, but beware of those twin turbos and check them carefully before handing over the cash. In fact, many 1JZ Soarers were privately imported into Australia, so they are more common than you might imagine.
In Australia, the Ford Barra vs 2JZ debate continues to rage. Both engines have their strengths, but the fact remains that they have a lot in common.
They are both good solid foundations to start modding, they both have good inherent strength from the factory and there is a huge aftermarket just waiting to supply modders with everything they need.
Done right, either engine can be a world beater, but the Toyota unit will always have global appeal.