Hyundai Theta engine


The Hyundai Theta is a gasoline four-cylinder automobile engine family. The third all-aluminum engine of Hyundai Motor Company debuted in the fourth-generation Hyundai Sonata sedan (codenamed NF), which was unveiled in August 2004 in South Korea. Hyundai Motor Manufacturing Alabama (HMMA) built a Theta II engine shop on the grounds of their Montgomery, Alabama automobile factory.

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      Theta engine
Overview
ManufacturerHyundai Motor Company
Layout
ConfigurationInline-four
Displacement110 cu in (1,798 cc)
122 cu in (1,998 cc)
144 cu in (2,359 cc)
Cylinder bore86 mm (3.4 in) (2.0L)
88 mm (3.5 in) (2.4L)
Piston stroke86 mm (3.4 in) (2.0L)
97 mm (3.8 in) (2.4L)
Block materialAluminium
Head materialAluminium
ValvetrainDOHC
Compression ratio10.5:1 (2.0 L)
10.3:1 (2.4 L MPi)
11.3:1 (2.4 L GDi)
Combustion
Fuel systemMPI
GDI
ManagementEMS-II from Siemens VDO
Fuel typeUnleaded gasoline
Oil systemPressure feed
Cooling systemWatercooled
Output
Power output107 kW (143 hp) at 6000 rpm (2.0 L)
121 kW (162 hp) at 5800 rpm (2.4 L)
Torque output190 N⋅m (140 lb⋅ft) at 4000 rpm (2.0 L)
222 N⋅m (164 lb⋅ft) at 4250 rpm (2.4L)
Dimensions
Dry weight134 kg (295 lb) (2.0L)
Chronology
PredecessorBeta
SuccessorSmartstream G2.0/G2.5/G2.5T

Global Engine Alliance
Main article: Global Engine Alliance

The Global Engine Alliance was a joint venture between Chrysler, Mitsubishi Motors, and the Hyundai Motor Company for developing a line of shared 4-cylinder engines. The initial design of the engine block and cylinder head was handled by Hyundai. However, each manufacturer configured their variants of the initial design differently based on their needs. In 2009, Chrysler bought out Mitsubishi and Hyundai's stake in the joint-venture; however, each company retained rights to build the engines.

Technical details

Theta

The engine features hollow stainless-steel dual overhead camshafts (DOHC) with powder-metal cam lobes, pent-roof combustion chambers and shimless bucket tappets in the cylinder head. BorgWarner Morse TEC supplies the complete timing system which uses the company's proprietary silent timing chains. Continuously variable valve timing (CVVT) works on the intake side.

The aluminum alloy engine block, which is formed using a high-pressure die-cast method, has a unique Metaldyne-supplied cassette-type balance shaft module with a two-stage oil pump built-in. In the lower-end, the block is reinforced by a ladder frame. Other notable features include fracture-split sinter-forged connecting rods manufactured by Sinteron and a stainless-steel exhaust manifold.

Theta's EMS (engine management system) software is EMS-II from Siemens VDO and the 32-bit PCM (Powertrain Control Module) calculates the amount of intake air by utilizing a contamination-proof hot-film type MAF (mass air flow) sensor.

The first version of the Theta Engine had three variants, 1.8L, 2.0L and 2.4L.

1.8L (G4KB)

The 1.8L version is an inline 4-cylinder engine that carries a 10.5:1 compression ratio; the engine makes 135 PS (99 kW; 133 hp) at 6,200 rpm and 16.9 kg⋅m (122 lb⋅ft; 166 N⋅m) of torque at 4,250 rpm.

2.0L (G4KA)

The 2.0L version is an inline 4-cylinder engine that carries a bore and stroke of 86 mm and a 10.5:1 compression ratio; the engine makes 145–151 PS (107–111 kW; 143–149 hp) at 6,000 rpm and 19.3–19.8 kg⋅m (140–143 lb⋅ft; 189–194 N⋅m) of torque at 4,000–4,250 rpm. It uses a timing chain instead of belt, and the engine dry weight is 134 kg (295 lb).

2.4L (G4KC)

The 2.4L version is an inline 4-cylinder engine that carries a bore of 88.0 mm, stroke of 97.0 mm and a 10.5:1 compression ratio; the engine makes 165 PS (121 kW; 163 hp) at 5,800 rpm and 22.3 kg⋅m (161 lb⋅ft; 219 N⋅m) of torque at 4,250 rpm.[1]

Theta II MPi

The second generation Theta engine added CVVT on the exhaust side as well as a two-way VIS and comes in two sizes, the 2.0L (G4KD) and 2.4L (G4KE).

2.0L (G4KD)

The 2.0L Theta II MPi engine has a 10.5:1 compression ratio, and it produces 165 PS (121 kW; 163 hp) at 6,200 rpm and 20.2 kg⋅m (146 lb⋅ft; 198 N⋅m) of torque at 4,600 rpm.

2.4L (G4KE/G4KG)

The 2.4L Theta II MPi engine has a 10.3:1 compression ratio, and it produces 178 PS (131 kW; 176 hp) at 6,000 rpm and 23.2 kg⋅m (168 lb⋅ft; 228 N⋅m) of torque at 4,000 rpm.

Theta II GDi

The Theta II GDi was announced in November 2009 starting with the 6th generation Sonata, improvements include switching to GDI.

2.4L (G4KJ)

The 2.4L Theta II GDi engine has a 11.3:1 compression ratio, early versions were rated at 201–203 PS (148–149 kW; 198–200 hp) at 6,300 rpm and 25.5 kg⋅m (184 lb⋅ft; 250 N⋅m) of torque at 4,250 rpm while later versions were rated at 188 PS (138 kW; 185 hp) at 6,000 rpm and 24.6 kg⋅m (178 lb⋅ft; 241 N⋅m) of torque at 4,000 rpm.

Theta II Turbo MPi

The Theta II Turbo MPi was used in the Genesis Coupe. The turbo used is a Mitsubishi TD04 model.

The Theta II Turbo MPi block used is very similar to the 4B11T engine found in Mitsubishi Lancer Evolution X, as core components like pistons and rods are said to move freely between them,[2] however, the two engines are not identical. The 4B11T is a semi-closed deck block with larger oil and coolant passages, where as the Theta is an open deck block.

2.0L (G4KF)

The 2.0L MPI turbo in the 2009–2012 Genesis Coupe, it produced 210–213 PS (154–157 kW; 207–210 hp) at 6,000 rpm and on 91 RON/87 octane (AKI) gasoline, and 226 PS (166 kW; 223 hp) at 6,000 rpm on 98 RON/93 octane (AKI). Torque remains the same at 30.5 kg⋅m (221 lb⋅ft; 299 N⋅m) at 2,000 rpm.

For the facelifted 2013–2014 Genesis Coupe, the engines got upgraded with a new twin-scroll turbocharger with new version now producing 260–264 PS (191–194 kW; 256–260 hp) at 6,000 rpm and 36 kg⋅m (260 lb⋅ft; 353 N⋅m) of torque between 2,000 and 4,500 rpm on 91 RON/87 octane (AKI) gasoline, and 275–279 PS (202–205 kW; 271–275 hp) at 6,000 rpm and 38 kg⋅m (275 lb⋅ft; 373 N⋅m) of torque between 2,000 and 4,500 rpm on 98 RON/93 octane.

2.0L (G4KH)

The 2.0L GDI turbo in 6th generation Sonata and 3rd generation Optima develops 271–278 PS (199–204 kW; 267–274 hp) at 6,000 rpm and 37.2 kg⋅m (269 lb⋅ft; 365 N⋅m) of torque between 1,750 rpm and 4,500 rpm.

For the 7th generation Sonata and 4th generation Optima, the engine develops 245–248 PS (180–182 kW; 242–245 hp) at 6,000 rpm and 36 kg⋅m (260 lb⋅ft; 353 N⋅m) of torque between 1,350 rpm and 4,000 rpm.

For the i30N and Veloster N, the engine develops 250–275 PS (184–202 kW; 247–271 hp) at 6,000 rpm and 36 kg⋅m (260 lb⋅ft; 353 N⋅m) of torque between 1,450 rpm and 4,700 rpm.

2.0L (G4KL)

For the Genesis G70 and the Kia Stinger, the engine develops 252–255 PS (185–188 kW; 249–252 hp) at 6,200 rpm and 36 kg⋅m (260 lb⋅ft; 353 N⋅m) of torque between 1,400 rpm and 4,000 rpm.

2.0L (L4KA)

The 2.0 L (1,998 cc) engine features LPI injection and makes 136–141 PS (100–104 kW; 134–139 hp) at 6,000 rpm with 18.7–19 kg⋅m (135–137 lb⋅ft; 183–186 N⋅m) of torque at 4,250 rpm.

Applications

Theta/Theta-II (2.0L)
2.0L DOHC engine in a Kia (G4KD)

(G4KA, G4KD)

Theta/Theta-II (2.4L)

(G4KC, G4KE, G4KG, G4KJ)

Theta-II 2.0 Turbo (2.0T)
2011 Hyundai Sonata Limited 2.0T, turbo GDI engine

(G4KF, G4KH, G4KL)

Engine recall

Hyundai and Kia vehicles equipped with Theta II engines were recalled, due to the fact that those engines were, and continue to be, the subject of an investigation by the National Highway Traffic Safety Administration (NHTSA). Safety regulators are investigating if Hyundai and Kia did enough in a timely manner with regards to the recalls of nearly 1.7 million vehicles with Theta engines, which were prone to an abnormal amount of noise and seizing.

In September 2015, Hyundai recalled about 470,000 model year 2011-2012 Sonatas equipped with 2-liter and 2.4-liter Theta II engines. At the time, Hyundai told NHTSA that manufacturing problems left metallic debris around the engine crankshaft, causing problems with oil flow. The pieces of metal interfere with the oil flow through the connecting rod bearings and damage the connecting rods. The automaker blamed the problem on a mechanical "deburring" process used to remove metallic machining debris from the crankshaft.[3]

By April 2017, Hyundai expanded the 2015 recall by including another 572,000 vehicles with Theta II engines, including 2013-2014 Hyundai Sonata and Santa Fe Sport vehicles.[4] Hyundai told safety regulators the same metal debris problem caused the expanded recall. Near that same time, Kia told NHTSA about a recall of more than 618,000 model year 2011-2014 Kia Optima, 2012-2014 Sorento and 2011-2013 Sportage vehicles because the Theta engine bearings wore out too early and caused the engines to seize.[5] Kia said it didn't recall the vehicles in 2015 when Hyundai first recalled its cars because the Theta II engines in the Kia vehicles were built on a different production line and had different problems than Hyundai. In addition to customers complaining about the Theta II engines, a Korean whistleblower who worked for Hyundai as an engineer let NHTSA know what he knew.

Owners started suing after the automaker refused to pay the thousands of dollars to repair or replace the engines, with one lawsuit from 2015 alleging a dealer wanted $4,500 to do the work. Kia was also served papers over a class-action lawsuit in 2016 filed by owners of vehicles equipped with Theta engines. NHTSA says it took action to "investigate both the timeliness and scope of Hyundai's Theta II engine recalls, and Hyundai's compliance with reporting requirements."[6]

In Canada in 2019 Hyundai announced a recall for most vehicles using the affected engines,[7] however a class action lawsuit was filed in 2018 as a result of failures of this engine used in Canadian Forte models and lack of manufacturer support against Hyundai Canada.

On December 1, 2020, Hyundai and Kia recalled 423,000 vehicles equipped with various engines following a joint review by Hyundai and the NHTSA, of which the 2.4L Theta II MPI engines were a part of. This marks the first instance of the MPI variants of these engines being recalled. Affected vehicles include the 2011-2013 Hyundai Sonata Hybrid, 2012 Hyundai Santa Fe,[8] 2012-2013 Kia Sorento, 2011-2013 Kia Optima Hybrid, 2012-2013 Kia Forte and Forte Koup, and the 2012 Kia Sportage.[9]

Based on information from Hyundai Motor company (korea), this recall is not applicable in the ASIA PACIFIC market.

Crate engines

On 2013-11-05, Hyundai announced the creation of a new factory crate engine program at the 2013 SEMA Show in Las Vegas, which initially included a 2.0-liter, turbocharged four-cylinder engine. The crate engine program began in December 2013.[10]

See also

References
  1. "Archived copy". Archived from the original on 2014-11-08. Retrieved 2014-02-06.CS1 maint: archived copy as title (link)
  2. Aaron Robinson. "2010 Hyundai Genesis Coupe 2.0T Turbo". Car and Driver (May 2009).
  3. "Part 573 Safety Recall Report 15V-568" (PDF). NHTSA.gov. September 10, 2015. Retrieved March 5, 2020.
  4. "Part 573 Safety Recall Report 17V-226" (PDF). NHTSA.gov. March 31, 2017. Retrieved March 5, 2020.
  5. "Part 573 Safety Recall Report 17V-224" (PDF). NHTSA.gov. March 31, 2017. Retrieved March 5, 2020.
  6. "Hyundai and Kia Theta II Engine Recalls Investigated". CarComplaints.com. Retrieved 2018-07-17.
  7. "Automobile Protection Association | Two major recalls and a warranty extension from Hyundai and Kia Canada". www.apa.ca. Retrieved 2019-12-11.
  8. "Part 573 Safety Recall Report 20V-746" (PDF). NHTSA.gov. December 1, 2020. Retrieved December 10, 2020.
  9. "Part 573 Safety Recall Report 20V-750" (PDF). NHTSA.gov. December 2, 2020. Retrieved December 10, 2020.
  10. Hyundai launches crate engine program with 2.0L four and 3.8L V6
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