Toyota’s first V6 engines introduced many changes that are even still used even up to this day. These automotive adaptations lead to out-of-the-box innovations that thrived in the many years to come. And one of those engines is the VZ engine family. And we will mainly discuss the 1VZ-FE engine.
Let’s talk about the engine’s design, applications, tuning potential, reliability, issues, technologies, and many more.
Let’s get right to it!
What is a Toyota 1VZ-FE Engine?
The Toyota 1VZ-FE is a 2.0 Liter, water-cooled, naturally-aspirated, V-type six-cylinder gasoline engine produced by the Japanese automaker Toyota Motor Corporation from 1988 until 1991. This engine offers outstanding performance for a two-liter machine with its low fuel consumption, high torque and power production for dynamic acceleration that ranges from low to high RPM, and supreme quietness.
This engine combines skillful engineering that maximizes Toyota’s valve mechanism technology and special features of the V-engine. It was first developed for the Toyota Prominent in the late 1980s and is considered the world’s first top-class V6 engine with a quad-cam and 24-valves.
1VZ-FE incorporates a scissor gear design to alleviate gear backlash and convert ninety percent or more of the maximum torque over an RPM range that stretches from 2,500 to 6,000, giving the driver a dynamic acceleration performance.
It features a solid cast-iron cylinder block and aluminum cylinder heads, equipped with Toyota Computer Controlled System (TCCS), Electronic Fuel Injection System (EFI), and Acoustic Control Induction System (ACIS), three of the most technologically advanced automotive systems in that period for better engine efficiency.
Toyota 1VZ-FE is a member of the VZ engine family, which is Toyota’s first V6 engine and their attempt to go head-to-head against the Nissan’s VG engine.
Engine Specifications and Design:
- Production Run: 1988 – 1991
- Cylinder Block Material: Cast-iron
- Cylinder Head Material: Aluminum
- Configuration: V6
- Bore: 78.0 mm
- Stroke: 69.5 mm
- Valvetrain: DOHC with four valves per cylinder
- Displacement: 2.0 L (1992 cc)
- Compression Ratio: 9.6
- Weight: 425 lbs.
- Max HP: 136 HP at 6,000 RPM
- Max Torque: 128 lb-ft at 4,600 RPM
The engine has a cylinder bore of 78 mm, a 69.5 mm piston stroke, and a 9.6 compression rating. The 1VZ-FE engine was rated at a maximum power of 136 HP at 6,000 RPM and a maximum torque of 128 lb-ft at 4,600 RPM.
The cylinder block of the 1VZ-FE engine is made from cast iron and has six cylinders arranged in a ‘V’ format at a bank angle of 60-degrees which minimizes basic engine vibrations. The cylinder liner walls are uneven surface ribs to enhance the rigidity, resulting in lower noise and vibrations.
It employs a dual-mode crankshaft and a one-piece bearing cap. Four bearings made from copper and lead alloy support the crankshaft inside the crankcase. The 1VZ-FE engine is also integrated with five rubber engine mounts which increases the rigidity of the mount brackets to minimize the vibration sent to the vehicle body.
Oil holes are drilled and placed at the crankshaft center for supplying oil onto the mechanical parts such as pistons, connecting rods, and other internal components. The engine’s firing order is 1-2-3-4-5-6. The crankpin diameter is 48 mm, and the crankshaft main journal diameter is 64 mm.
The 1VZ-FE pistons are made from high temperature-resistant aluminum. Built on the piston heads is a depression clearance. It is to prevent the pistons from interfering with the opening and closing of the valves. The piston pins are semi-floating, with pins secured to the connecting rods by pressure fitting, allowing the pins and pistons to float.
The 1VZ-FE cylinder heads are made from aluminum alloy and have a double-overhead camshafts design with four valves per cylinder – two for both intake and exhaust valves. These valves are designed to have a larger area and a lighter weight, resulting in a higher intake and exhaust efficiency on different RPM ranges.
With the help of ACIS technology, the engine provides optimum control of the intake pathway over the complete RPM range. That also increases the power and intake efficiency. Additionally, Toyota installed a knock sensing device to control the ignition timing for a higher compression ratio and a bigger torque.
Toyota took advantage of the ‘V’ configuration by decreasing the valve angle to 22-degrees, making it closer to vertical. The pentroof-shaped combustion chamber was made more compact, allowing the position of the spark plugs right at the center of the chamber, increasing the squish area for a more efficient burn and greater combustion efficiency.
The intake camshafts are driven via a single belt, and a scissor gear on the intake camshaft is engaged with a gear in the exhaust camshafts which drives it. The camshaft journal is supported at four exhaust and five intake places between the front end of the cylinder head and the valve lifters.
In addition, Toyota combines their advanced fuel injection and ignition technologies through TCCS (Toyota Computer Controlled System), which is the prime reason for lower fuel consumption. As a result, this engine is one of the most recognized in fuel economy across 2-Liter V6 machines.
Some applications of the 1VZ-FE engine:
- 1988 – 1991 Toyota Camry Prominent
- 1988 – 1991 Toyota Vista
Engine Tuning, Upgrades, and Modification
The 1VZ-FE is a good engine platform if you want a sleeper dressed in a luxury kind of vehicle. It is pretty smooth and secretly aggressive in some way, even with its smaller displacement. The tuning and upgrade potential is there, and it would be worth upgrading the engine.
The first step is to service it for port and polish; if you can do it yourself, it is better; if not, take it to someone specializing in that department. After that, buy some performance parts such as headers, cold air intake, and 2.5-inch performance exhaust. Install all of these upgrades and configure the ECU; this can get you around 165 HP at the crank. Add some performance cams with 262/262-degree lift, and gain an extra 10 HP.
You can stretch the power production to a higher number up to 200 HP by buying or swapping it with a more aggressive engine. In some cases, you can consider another option is to build a turbo kit using turbochargers used for Celica Supras, make turbo manifolds, and do everything in custom.
When tuning the 1VZ-FE, avoid increasing the compression ratio, buying an intake manifold and lighter pistons. It is extremely expensive, and the power gained is not parallel to the price.
Problems Surrounding Toyota 2VZ-FE:
The Toyota 1VZ-FE is a highly reliable and durable engine. Carrying that reputation, as the machine goes down the wire, issues somehow found a way to catch its time, resulting in some weaknesses and shortcomings, which, unfortunately, shared across all machines. Some troubles might arise and affect the engine’s performance and the overall system, so we created a heads-up list of the risks involving the 1VZ-FE engine. These do not occur on all of 1VZ-FE but are encountered mainly by a small percentage of owners.
The 1VZ-FE engine is old enough since it was produced more than two decades ago. And sure enough, the common problem with an old machine is its excessive oil consumption due to loose components and deteriorating parts. There could have been an increase in the wear of the connecting rods, and sometimes cylinder head cracks occur.
Most of the time, these kinds of troubles are out of our control since it happens internally and all we can do is provide the engine with quality oils.
Another common problem of the 1VZ-FE is engine overheating. When overheating escalates badly, it is hard not to mention high temperatures in the engine. This issue is caused by the loss of coolant supply flowing in the engine. When talking about engines and temperature, oil deprivation is crucial, perhaps detrimental, resulting in severe damage to the machine, which affects engine performance and is highly costly.
To know, check the coolant level; if it is low, the problem is in the head gasket; there might be a leak. If the level is normal, check the cooling fan because these fans often fail. After inspecting and checking everything and none of those appeared to be the reason. Check the radiator cap, radiator condition, and thermostat; it might be there.
Engine knocking is also another issue that needs to be brought up. 1VZ-FE is installed with knock-sensing devices, so it is not hard to find where the knocks are coming from. Moreover, these foreign sounds indicate your engine that it is game over already, but no, you can resolve this by adjusting the valve clearances, and if the sound goes away, then you’re good to go. If not, bring it to a specialist to check thoroughly.
Always use the recommended high-quality engine oil and avoid compromising for lubricants and fuels. Have the engine serviced regularly and constantly monitor the condition of the cooling system.
A V6 engine equipped with top-of-the-line models seems like a far-fetched idea, but Toyota materialized and proven that V6 can contest the four-cylinder in terms of performance. The ice-breaker of the VZ engine, in its emergence, surprised the world with its engine design and overall engine efficiency. It is Toyota’s first quad-cam with a 24-valve in addition to their long line of engines lined up for their Camry Prominent vehicle.
This engine has unique attributes that can be easily distinguished; its quietness is the most apparent but highly underrated characteristic. In addition to that, the technologies integrated are advanced in that era which paved the way for others.
Age as being its weakness and no other design flaw; this engine is solid and highly respected across the automotive industry. MZ and GZ, which are also Toyota-made, are the descendants of this machine.
I hope that this simple discussion helped you understand the 1VZ-FE’s engine design, specifications, applications, issues, reliability, tuning potential, and overall impact on the industry and community.