1JZ engines are one of the top-notch engines to hit the road and was a huge name stand-out in the ’90s, well up until today. It is used for multiple engine swaps and powers many recognizable Japanese cars. That is why many enthusiasts still want a piece of this powerplant. It produces a satisfying amount of energy without sweat and has incredible tuning potential ahead. So with that, let’s talk about the 1JZ engine’s power output, applications, issues, problems, aftermarket support, tuning potential and upgrades, and its overall impact on the industry.
What are 1JZ engines?
The Toyota 1JZ-GE is a more widely spread 1JZ engine member. it is a naturally aspirated machine that has its turbo modification, 1JZ-GTE. 1JZ-GE features belt-driven two overhead camshafts with four valves per cylinder (24 valves in total), an Aluminum cylinder head, and a cast-iron block. 1JZ-GE is equipped with a VVT-i system (Variable Valve Timing with Intelligence) on the intake side. Since its 1996 upgrade, an electronic fuel injection system, ACIS variable-length intake manifold, is also installed with the dual-stage intake manifold. All of these models came with a 4-speed automatic transmission as the primary standard; Toyota released no manual gearbox for this.
In 2007, the 1JZ engine production came to an end. The one that took its place as the successor is the 4GR-FSE engine.
Engine Specifications and Design:
- Production Run: 1990 – 2007
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Cast-iron
- Configuration: Inline-six
- Bore: 86 mm
- Stroke: 71.5 mm
- Valvetrain: DOHC with four valves per cylinder
- Displacement: 2.5 L (2492 cc)
- Compression Ratio: 10.1 for early release and 10.5 for the succeeding
- Weight: 455 lbs.
- Max HP: 198 HP at 6,000 RPM
- Max Torque: 185 lb-ft at 4,000 RPM
Toyota 1JZ-GE engine is a naturally-aspirated, non-turbo, 2.5 L, straight-six gasoline engine which Toyota produced from 1990 to 2007. The first generation of 1JZ-GE engine ran from 1990 – 1996 and has a mechanical distributor ignition system and a lower compression ratio of 10.0; let’s call this the 1JZ-GE. On the other hand, the 1JZ-GE VVT-i is the second-generation engine that is the extension of the first, and Toyota applied some changes that include the integration of the DIS-3 ignition system with three ignition coils, a higher compression ratio of 10.5, and a VVT-i system on the intake camshaft.
1JZ-GE engines are designed for rear-wheel drive and for longitudinal mounting, like all JZ engines. Its cast-iron block is a monoblock specially cast structure that utilizes seven support bearing systems with 86 mm bore and a 71.5 mm stroke. The crankshaft has twelve counterweights, and seven journals, both of the pins and journals are induction-hardened. The pistons are special casted Aluminum and are fitted with two compression rings and a single oil ring.
The 1JZ-GE cylinder head has a good cooling efficiency with its lightweight but strong Aluminum material with four valves per cylinder for a valve total of 24. It has double overhead camshafts made of specially cast steel and driven by the toothed timing belt. Solid shimless buckets are used instead of hydraulic lifters, and Toyota also installed a revised dual-stage intake manifold in this engine.
The output for the early non-turbo, non-VVT-i (1990 -1995 )1JZ-GE engine is 168 HP at 6,000 RPM and 173 lb-ft of torque at 4,800 RPM. In 1995, VVT-i was added to the engine for an increased output of 198 HP at 6,000 RPM and 185 lb-ft at 4,000 RPM. It has a redline of 7,500 RPM for the non-VVT-i and 7,000 for the VVT-i equipped.
Applications of the 1JZ-GE Engine:
- Toyota Mark II
- Toyota Soarer
- Toyota Chaser
- Toyota Cresta
- Toyota Progres
- Toyota Crown
- Toyota Crown Estate
- Toyota Mark II Bilt
- Toyota Verossa
- Toyota Supra
Engine Upgrades, Tuning, and Modifications:
For the 1JZ engine, tuning up or upgrading the machine requires a turbocharger to achieve your preferred power output and, at the same time, intensify it. So, suppose you want to purchase a naturally aspirated 1JZ-GE engine. In that case, you should buy performance camshafts with 272-degree duration, cold-air intake, 1JZ-GTE body, buy a performance exhaust system, and do some port and polish on the cylinder head. Installing all those parts and pair them with ECU aftermarket, you can get increased power and capacity of 250 HP. However, it is still practical to purchase a new 1JZ-GTE for an engine swap. It is also not better to turn your 1JZ engines into 2JZ because the 2JZ block is 14 mm higher, which requires shorter connecting rods for it to fit.
Problems Surrounding 1JZ-GE Engines:
As much as we wanted to keep our engines in pristine condition for our engines to last long, however, some things might not come in our way. This is due to factors such as wear and tear, age, external environment, and many more that affect the engine’s state and condition. With this, we created a precautionary list so that you will not find yourself treading waters in these issues. These are some common 1JZ problems that some owners had encountered and are too common not to notice.
First is the 1JZ-GE engine unable to start. Issues of this type can get into your nerves, especially if you are in the middle of a trip or have essential tasks to do, then suddenly the car won’t start. This condition is caused by the spark plugs and is prevalent among engine that sits at colder regions that causes the spark plugs to be damp or frozen. So you might need to screw the spark plugs out and dry them if they are damp; if that didn’t help, buy new spark plugs and install those. That will solve the problem.
The second is misfiring, which is the direct result if things went south on the spark plugs. Misfirings happen when the engine cylinder cannot burn the air-fuel mixture in the combustion chamber. This is due to faulty or worn-out engine components such as the piston ring, sparks plugs, MAF sensor, oxygen sensors, etc. As the engine loses power, it jerks aggressively and can escalate to fuel overconsumption and raised emissions output.
Next is the Rough idling. Rough idling is common not only to 1JZ but also to other engines outside the confinements of Toyota. It is caused by collective dirt accumulated that lies on the fuel injectors, clogged air filters, exhaust system issues, and spark plugs and wires. This is when your car is like shaking and cannot burn the fuel correctly due to the mentioned components above.
The third is the engine knocking sound. This is the most noticeable, if not one, out of all the issues due to its loud nature because you can hear it. The noise can be caused by the VVT-i system, unadjusted intake and exhaust valves, and connecting rod bearings. Check the valves first for the clearances. If the noise decreased or gone after adjusting it, then that’s it, but if you already adjusted the valves and nothing happened, replace the VVT-i, which is consumable and does not last that long so you might need to replace it. The timing belt tensioner bearing can also cause knocking; try replacing it.
Since 1JZ-GE engines were more than two decades ago and most of its components, especially if you bought it second-hand, are already loose and worn out. That results in excessive oil consumption, which is not that surprising to that engine age. However, too much oil consumption can affect the engine performance because you need to stock it often, and if not, it will result in an engine overheat or, worse, engine failure. So check your valve stem seals and piston rings regularly so that if they need replacements, you can do it immediately.
There are also reports that the water pump of the 1JZ engine does not last long.
1JZ-GE engines are highly reliable with their 200,000-mile life at a minimum and pose no significant problems apart from what we mentioned earlier, which are all common and minor. It is one of the most iconic engines that Toyota made, which can still be found up until today. It is a great platform for tuning, has widespread aftermarket support, and is even used by many for engine swaps due to its vast tuning potential. However, it is incredibly vital to take care of the engine, but it is not an easy task for a 20-year-old engine. With the correct proper and maintenance, this engine can last a lifetime and be passed on several generations.
I hope that this simple guide and informations helped you understand the 1JZ-GE engine’s power, output, applications, tuning potential, aftermarket support, issues, problems, and overall impact on the automotive industry and community.