One of the most sought engines of the Toyota company was its GR engine family. It offers countless engines and stretches its varieties more than the other families, making it won several engine awards and gaining popularity over time. And one of the engines that we will talk about from the GR family is the 7GR engine.
So with that, let’s talk about the engine’s design, power, applications, issues, problems, tuning potential, reliability, and many more.
What is a Toyota 7GR Engine?
The Toyota 7GR is modeled under the same badge as the Toyota 2GR-FKS engine, the newest 3.5 Liter V6 engine among all the versions of the 2GR engine. The key features of the 2GR-FKS engine were retained and integrated into the 7GR engine. Toyota 7GR engine is the analog of the 2GR-FKS engine and is meant to be marketed in the Chinese market.
It received Toyota’s latest advanced technology in that era which includes the reversible switch from the Otto cycle to Atkinson cycle for a better fuel economy. That improvement is attained using the VVT-iW (Variable Valve Timing – Intelligent Wide) on the intake camshaft, while the exhaust camshaft also uses variable valve timing. 7GR engines are equipped with a DIS coil-on-plug ignition system, Electronic Throttle Control System (ETCS-i), and Acoustic Control Induction System. Like the 2GR-FKS, 7GR machines have a combined port fuel injection (Toyota’s D-4S) and direct injection. The most notable observable change is observed in the exhaust system. The exhaust manifold is already integrated into the cylinder heads, and the exhaust gas valve (EGR) circuit is cooled.
Engine Specifications and Design:
- Production Run: 2016 – Present
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Aluminum
- Configuration: V6
- Bore: 94 mm
- Stroke: 83 mm
- Valvetrain: DOHC with four valves per cylinder
- Displacement: 3.5 L (3456 cc)
- Compression Ratio: 11.8
- Weight: 370 lbs.
- Max HP: 276 HP at 6,000 RPM
- Max Torque: 269 lb-ft at 4,500 RPM
7GR engines are designed for longitudinal layout and have an open-deck type cast-Aluminum alloy cylinder block with spiny cast-iron cylinder liners cast into the cylinder block material. These uneven surfaces increase the adhesion between the Aluminum cylinder block and the cylinder liners. The cylinder banks of the engine have a 60-degree in V arrangement.
There are inclined coolant channels drilled in between the cylinders. Spacers in the water jackets are also installed along with the mentioned channels to allow a more intensive coolant circulation near the cylinder top, which improves a more uniform thermal load and improves heat dissipation.
The block has a bore of 94 mm and a stroke of 83 mm. 7GR has a forged steel crankshaft supported by four journals and five balance weights held by individual main bearing caps. The connecting rods are forged that used Aluminum bearings. The crankshaft bearings are made from Aluminum, like the connecting rods’ bearing. The cylinder wall lining surface is micro-grooved for the optimum distance of oil clearance, reducing the engine vibration and significantly improving the cold-engine cranking performance. 7GR’s connecting rods and caps were made from high-strength steel and nutless-type tightening bolts to reduce weight.
The 7GR has compact T-shaped Aluminum pistons that feature polymer-coated skirts to reduce friction. This top piston ring is Alumite-coated for better wear resistance and connected to the connecting rods with fully floating pins. The piston walls are sloped, which distributes the load to the piston pin at the expansion stroke. Piston crowns, like the 2GR-FKS, have a tapered-squish design to reduce engine knocking and improve the engine’s thermal efficiency; the squish angle is designed to enhance the airflow, enhance flame travel, and promote swirls. The cylinder block utilizes piston oil jets on the left bank and right center of the block to provide lubrication and regulate the temperature of the pistons.
To add to that, the oil sump is comprised of a massive upper part and stamped steel lower sump; the oil level sensor is installed on the crankcase.
The cylinder head is a three-part separate housing: valve cover, camshaft housing sub-assembly, and cylinder head sub-assembly, all of which are made from Aluminum alloy. The camshafts are installed in different housings, mounted on the cylinder heads that make the design and manufacturing more simple. The intake camshaft is equipped with VVT-it for a smoother valve timing change according to different driving conditions and VVT-i on the exhaust camshaft and is made from cast-iron and chain-driven. The main timing chain drives the intake camshafts, and through the secondary chains, the exhaust camshafts are guided by the intake camshafts.
The engine also has steel-laminate type head gaskets between the cylinder heads and banks to enhance durability and sealing performance; 7GRs used a shim about the cylinder bore of the gasket. It has siamese intake ports to reduce wall wetting and hydrocarbon emissions due to the reduced overall surface area of the port walls. The engine’s exhaust manifold is installed into the cylinder heads, and there are roller rockers and valve adjusters in the valve mechanism.
Roller rockers arms drive valves with built-in needle bearings and a unique cam profile design to increase the valve lift versus the traditional shim-less lifter type of the first generation 1GR; it also reduces the friction between the camshafts and the roller rocker arms. At the same time, this increases the overall cylinder head height to cater to a slightly taller rocker system.
The 7GR engine has a plastic variable-length intake manifold driven by an Acoustic Control Induction System that chooses the proper length of the opening and closing of the intake air control valve depending on the driving conditions based on RPM.
The rated output of the 7GR engine is 276 HP at 6,000 RPM and 269 lb-ft of torque at 4,500 RPM.
Some applications of the 7GR engine:
- 2016 – Present Toyota Land Cruiser Prado (GRJ152L) (China only)
- 2019 – Present Toyota HiAce (GRH300)
Engine Tuning, Upgrades, and Modifications
7GR engine, like the 2GR-FKS, is not the best platform for naturally-aspirated tuning, and fortunately, there is a supercharger available for this engine. However, if you want to tune it this way, you need to buy pistons that can fit a 12.0 compression ratio, pair it with a performance camshaft and cold air intake; do some head porting and polish, 3-1 headers, performance exhaust system, and tune the ECU. These upgrades can help you reach at least 300 HP.
Another option to try is to buy a TRD or HKS supercharger kit, bolt it in the stock internals and get around 330 HP. If 330 HP is not enough, you may opt to increase the boost pressure to the maximum point by having a more powerful supercharger, 500 cc/min fuel injectors, pistons fitted to a 9.0 compression ratio, and an ECU upgrade.
Problems Surrounding 7GR Engines
Like most engines we have today, 7GR cannot elude the experience of having common issues. These problems are addressed to weigh the reliability and overall toughness of the engine under tremendous usage. And some issues may be common than others, we still want to make a prudent reminder for you to have an idea on some issues of the engine.
First is the oil leakage. Engine oil leaks come from different areas of the engine. However, in 7GR engines, leaks have something to do with the oil tube in the VVT-i lubrication system and other GR engines, especially the 2GR. The VVT-i tube is made from iron and rubber hose that feeds the oil, and generally speaking, rubbers are highly susceptible to wear-out breakage down the line and maybe the primary cause of the leak. Good thing that Toyota already solved this issue, even on the 2GR ones in 2010, and replaced the hose with a metal one. You might notice a minor leak due to some oil drops on the ground or produce some smoke; more significant leaks leading to rapid oil loss that plummets the oil pressure and creates a more prominent smoke.
Another issue that might arise is the noise coming from the engine, which is also caused by a lot of factors. But, as for the 7GR engine, this problem might be due to an idler pulley. You can hear an annoying squeaking sound from the engine bay. Take note that the idler pulley is situated between the cover plates. The plate outside the pulley goes to the engine; the plate inside is our target, which is the extra one, must be installed to secure the elimination of the squeaking sound.
And one last thing, the water pump failure. 7GR and other GR engine’s weak point is also in this department, as a member of the same engine family. Keep in mind that water pumps are a standard maintenance item and must be replaced periodically. Water pumps are vital to the engine performance as they cool down or regulate the operating engine temperature to avoid overheating and other heat-related issues.
So, with that being said, a faulty water pump is highly detrimental to the engine, considering that it involves coolant circulation. This issue happens due to the normal wear and tear of the water pump commonly occurring in unpredictable times, as it can happen anytime, especially on older models.
7GR engines are like a newer brother of the 2GR-FKS engine; it deserves a seat on the table compared to the 2GR engines as it is as technologically advanced, powerful, and added to the Otto-Atkinson switch makes the fuel consumption better than its peers. This 7GR engine has a lot to offer and will not disappoint any owner since it powered many Toyota engines. With the proper care, maintenance, and habitual observations, this engine can last at least 250,000 miles. Always use high-quality engine oil, gasoline, and schedule replacements, especially the water pump.
I hope that this simple instruction and discussion about the 7GR engine helped you understand its architecture, power, applications, issues, tuning potential, reliability, and overall impact on the automotive industry and community.