When we speak of most things that are 30 years old, it’s almost always in a reminiscing manner. Not many things, especially when technology is involved, still have the impact they once did 3 decades earlier. Tech is continuously evolving and just getting better and better each year. However, when it comes to the Toyota 2JZ engine it’s quite the opposite.

Not only is the 2JZ engine still relevant, but its phenomenal potential makes it the engine of choice for tuners even today. The 2JZ engine is still being pushed to its limit in many race cars 30 years after it first made its debut. There’s no denying that modern technology has helped take things to the next level, but that wouldn’t have been possible if the 2JZ engine didn’t allow for it. Here’s the story behind the most iconic inline-six-cylinder engine to ever be fitted to an automobile.

2JZ Engine – What Is It?

In short, the 2JZ engine is an inline-six cylinder unit that easily leaves V8 juggernauts such as the legendary LS9 in the dust. Like most six-cylinders, the 2JZ engine is very smooth This is because they are essentially two inline-three cylinder engines mated together. 

This results in a cancellation of opposing forces and perfect balance. In comparison, most V6 engines encounter an imbalance because the primary and secondary forces of the cylinders aren’t as canceled out as efficiently. This gives engines like the 2JZ a natural advantage and allows them to be pushed to higher RPM without compromising on safety.

While it’s closer to two inline-three cylinders in terms of its layout, the 2JZ engine shares quite a few similarities with an inline-four cylinder made by Toyota. It’s called the 3S-GTE and has the same square bore and stroke of 86 mm, just like the 2JZ engine. 

The biggest benefit of having a square configuration and the reason manufacturers choose it is to get a good balance of power and torque. With the 2JZ engine, Toyota achieved just that. The similarities don’t end there, the exhaust (29 mm) and intake (33.5 mm) valves were of the same size as well.

What Makes the 2JZ Engine So Strong?

It’s a commonly known fact that the 2JZ engine is incredibly strong. The source of its strength comes from several specific design solutions that Toyota chose to use, with the most notable one being a closed deck cast iron block. It’s certainly a neat feature, but it isn’t exactly unique. 

What made the closed deck cast iron block on the 2JZ engine stand out is the fact that it was reinforced. Toyota achieved this by using a set of tactically placed ribs that helped with rigidity. It is believed that this improvement was made after learning the shortcomings of the 2JZ’s predecessor – the 7M. 

These ribs that added reinforcement worked as oil return holes. Additionally, making the block out of cast iron also helps keep everything rigid and strong. 

However, Toyota didn’t stop there, other components like the journals of the crankshaft and main bearing caps were more durable. As a result, they didn’t have trouble being pushed beyond factory recommendations. 

Another addition that increased strength was a girdle installed between the oil pan and the block that takes care of any swing in the main caps. That’s not all though, the gasket that was used by this block was made of three layers of steel. This was another area where Toyota made use of the learnings from the older 7M engine which used a gasket made of fiber.

As for the 2JZ engine’s internals, as you’d expect, have been beefed up as well. The crankshaft, for instance, is counter-weighted and made of forged steel. The connecting rods are also forged and capable of withstanding a lot of abuse. The later versions of this engine featured slightly weaker connecting rods. This was a change that came about with the introduction of variable valve timing. Speaking of comparatively weaker components, the pistons were not forged even though many assume them to be.

The pistons used are high-pressure cast hypereutic. Even though they are inherently not as strong, they can still handle an impressive amount of power. These pistons are capable of handling around 750 HP! The friction reduction and thermal coating help them achieve such insane power figures. 

Speaking of the pistons, the ones on the turbocharged 2JZ engine featured a small hole at the bottom that worked as an oil gallery. This paired with the oil squirters on the block made for a well-lubricated powerplant that always has its temperature in check. 

Highlights of the 2JZ Engine

The 2JZ engine is really special. However, just the fact that it’s an inline-six with strong internals doesn’t make it the engine that it is. The 2JZ engine without variable valve timing has a compression ratio of 10.0:1, while the one with has a compression ratio of 10.5:1. On the other hand, the turbocharged 2JZ engine has a compression ratio of 8.5:1 which is much lower, allowing it to handle high boost pressure.

The 2JZ engine also has proper dual overhead camshafts, meaning both camshafts are controlled by the timing belt. This engine also features 4 valves per cylinder taking the total to 24 valves. The 2JZ engine features a well-shaped intake and exhaust port design. As it turns out, this would be one of its biggest design flaws. 

Not only is the flow inadequate when compared to newer engines, but it was also inferior compared to some of the engines from the same period. As a result, highly-modified 2JZ engines will always have an upgraded head. These come with reshaped ports that improve flow and allow for power figures above the 750 HP mark. Another highlight of the 2JZ engine is that it uses a non-interference configuration, which is a great thing when you’re pushing it hard and want to avoid pistons shaking hands with your valves. 

However, opting for a non-interference configuration came at a cost. Toyota had to equip the 2JZ engine with less-aggressive camshaft specifications. They were nowhere near the limit of the engine’s capabilities. This is exactly why upgrading the cams is quite a common modification. Changing the cams is fairly straightforward and can deliver an impressive power bump. Speaking of cams, it’s important to know that the 2JZ engine uses buckets on the valves and shims allowing adjustment of the valve lash. While that’s a less-complex system than hydraulic valve lifters, it’s a limiting factor when upgrading the camshaft.

The turbocharged version of the 2JZ engine uses sequential twin turbos. One of these turbos operates at lower RPMs, while the other is reserved for use at higher RPMs. The higher RPM turbo comes alive at 4000 RPM. Interestingly enough, both turbos on the 2JZ engines are the same size. This is quite uncommon as many twin turbo vehicles use different size units. What made the twin-turbo setup on the 2JZ engine really special was that it featured a beautifully linear powerband in stock form. These turbos were developed with the help of the Japanese conglomerate Hitachi. 

How to Modify the 2JZ Engine?

The 2JZ might just be the most highly modified engine in existence. Finding a stock one is rare. As a result, there are many ways in which one can go about modifying this engine. Once you begin your research, you will quickly realize that it’s quite the rabbit hole. However, we’ve listed the most basic ways you can make more power.

2JZ Engine – Modifications for 750 HP

Let’s begin with the changes you’d need to get around the popular 750 HP mark. The modification recipe for this is so well-known and, to be honest, not that complicated. First, you have to replace the factory twin turbo setup with a single turbo. This single turbo will be an aftermarket unit and much larger than the factory turbos. 

While this will take away from the linear powerband of the twin-turbo setup, it will reward you with a huge surge in power. You may have come across videos of modified 1998 Toyota Supras losing traction before surging ahead at a phenomenal speed. This is exactly the route most 2JZ engine owners take. However, the bigger turbo and the sudden power gain that comes with it require more fuel.

This is why the next modification needed is a more powerful fuel pump and higher-capacity injectors. In this application, 900cc or 1100cc injectors are often the way to go. Most people manage to achieve the 750 HP mark with factory camshafts. However, switching to aftermarket ones will make achieving the power goal easier. It’s also a good idea to get stiffer valve springs. Another necessary supporting modification is a front-mounted intercooler. You’ll want to keep the oil cool in a single turbo, high-power build. This intercooler will be considerably larger than the small side-mounted unit. 

In terms of tuning, the 2JZ engine will need a stand-alone ECU. There are quite a few options available on the market, but it’s recommended to find one that has the easiest installation method as wiring can get quite complicated. Once you have all these modifications in place, all that the engine requires is some tuning, and it should be good for 750 HP!

2JZ Engine – Modifications for up to 1500 HP

Some of the most unbelievable car launches I’ve seen have the 2JZ engine under the hood. While 750 HP is an absurd amount of power already, the 2JZ engine is capable of making more. Almost twice as much! Modifications get a little more serious when you want the 750 HP and that’s to be expected. The engine has to be torn apart and upgraded with forged internals.

Earlier, we discussed how the pistons weren’t the strongest in the 2JZ and that’s exactly why they need to be replaced with forged ones. The connecting rods also have to be forged units. The most common options would be pistons made of 2168 alloy and connecting rods made with 4340 steel. These are much stronger than the factory units and designed to handle an incredible amount of power. As we mentioned earlier, the 2JZ has a strong forged crankshaft from the factory, and it will work in this application. Yes, the factory crankshaft can handle up to 1500 HP!

That being said, some people prefer to switch to a billet crankshaft since they are already in the process of building the engine. While that will improve strength, such an upgrade is overkill for most builders. Similarly, one can also replace the block with an upgraded unit. This is quite unnecessary and only really required if you are looking at demolishing the drag strip. With the forged internals in place, it’s time to install an even larger single turbo. At this stage, you can also switch back to a twin-turbo setup where the smaller turbo feeds the larger one to make an incredible amount of power.

A fully built engine will need fuel…lots of fuel. That’s why most 1000+HP Supras run 12 injectors! That is 2 per cylinder in order to reach 2000cc of fuel. These injectors need two or three fuel pumps to deliver the necessary fuel flow. And all of this is just the beginning. Engines of this type need many supporting modifications. That said, even after all these modifications which can be quite expensive, a fully built Supra will give you hypercar levels of performance for a fraction of the cost!

2JZ Engine – Price and Availability 

The tremendous potential of the 2JZ engine has certainly made it less affordable. While this engine was available for $4000-5000 for the longest time, it recently doubled in value and now costs around $10,000. 

While that might sound like quite a sweet deal for a platform that can handle 1500 HP, one has to realize that an engine built to withstand that power level can cost $50,000, or even higher. However, the 750 HP build mentioned above will cost significantly less and that continues to make it a highly sought-after engine.

2JZ Engine – What to Watch Out For?

While the 2JZ engine certainly has a lot more positives than negatives, it’s a good idea to know about the common problems. Here’s what you need to watch out for.

Crank Pulley Disconnects

The crank pulley on the 2JZ engine is a wear item. It’s common for owners to forget this, which leads to the crank pulley failing and coming apart. Toyota recommends replacing the crank pulley every 60,000 miles. We recommend replacing it every 10 years regardless of the miles on it.

VSV Actuator Problem

Sometimes, stock twin turbo 2JZ engines can have boost issues. The most common problem that causes it is bad VSV actuators. They are vacuum switching devices that help control the sequential turbos, and they can get clogged. When this occurs, they fail to operate correctly leading to turbocharger-related problems.

Timing Belt Tensioner Bracket Failure

The timing belt tensioner bracket on the 2JZ engines is made from cast steel. This factory unit is known to fail in higher horsepower applications. Not just that, age and multiple heat cycles can also affect the longevity of this part. When it fails, it can cause the timing belt to get disconnected. And that’s something you don’t want happening even though it’s a non-interference engine. 

Bad Oil Pump Seal

Seals are known to wear out over time and shouldn’t come as a surprise if the oil pump seal goes bad on your 2JZ. This is one of the most common seal failures when it comes to this engine.

We Know All About the 2JZ Engine!

Newparts.com has a highly experienced team that knows what it takes to keep a 2JZ alive! If there’s something you need, head to our Shop and get your order in place. 

We offer genuine, OEM and aftermarket spares at highly competitive prices. We also stock parts for almost every well-known car brand! Our simplified menu should help you find the parts you need, but if you still require any assistance, feel free to reach out to us.