In 2003, Chrysler introduced the third generation HEMI, dubbed the 345 HEMI to commemorate its 345 cubic inch displacement. It's a long-running pushrod engine that debuted in the 2003 Dodge Ram, but has been significantly upgraded for better efficiency and performance.
A great sounding engine with a lot of things to know. But what are these engines really? let's find out
What are Dodge Hemi 5.7 liter engines?
The Dodge Hemi, a 5.7 liter engine, is a third generation iteration of the "HEMI" engine that began in the early 1950s. Back then, the concept was already established and applied to their military trucks back then. Chrysler developed the engine for the Republic P-47 Thunderbolt fighter jet.
The first HEMI V8 engines were not labeled as HEMIs, but instead referred to as "Firepower". They have the same hemispherical combustion chambers and two spark plugs per cylinder.
Because of these qualities, Briggs Cunningham installed these engines in his racing cars for international motorsport and won the race in 1953.
Fast forward to the present, HEMI engines continue to thrive and what we now have is decades of experience and dedication to the craft. It was even named one of Ward's top ten engines four years in a row from 2003 to 2007 and again in 2009.
The third generation HEMI picked up where the second generation left off. Combustion is different, with more complex engine heads, a coilless ignition system and two spark plugs per cylinder.
Chrysler introduced a variable valve timing system to these machines that achieve nearly 4% better fuel efficiency.
The HEMI 5.7 also features variable displacement technology, as does Mercedes' cylinder deactivation system, which deactivates two cylinders at low loads to improve fuel economy.
Engine Specifications and Design:
- Production run: 2003 – present
- Cylinder head material: aluminum
- Cylinder block material: cast iron
- Configuration: V8
- Bore: 99.49mm
- Hub: 90,88 mm
- Valvetrain: SOHC pushrod V8, two valves per cylinder
- Displacement: 5.7 l (5,654 cm³)
- Compression ratio: 9.6 and 10.5 (MY 2009+)
- Weight: 560 pounds.
- Maximum HP: 395 HP at 5,600 rpm
- Maximum Torque: 410 lb-ft at 3,950 - 4,400 rpm
The 5.7-liter HEMI is the only petrol engine available in the Ram Heavy Duty. Chrysler released this engine for the 2002 model year Dodge Ram 2500 and 3500 and 2003 models of 1500 pickup trucks to upgrade the Magnum 5.9 engine.
Chrysler made the HEMI 5.7 available for all 2004 Dodge Durango, Dodge Ram, 2005 Chrysler 300C, Jeep Grand Cherokee, Dodge Magnum R/T and many more. Manual transmission applications do not have cylinder deactivation.
The 5.7-liter HEMI's frame design started with the circuit board; it has no design basis. Similar to the 4.7-liter PowerTech V8, the HEMI 5.7 features a cast-iron, deep-skirt cylinder block with a 90-degree angle between the cylinder banks. The crankshaft is made of ductile iron and is supported by four main pins per bearing.
The engine uses forged powder metal connecting rods and skirt coated aluminum pistons. Until 2008, the pistons had narrow piston rings, but they were later narrowed in the 2009 revision.
The chain-driven overhead camshaft is located between the cylinder banks and has a longer timing chain to reduce the length of the tappets.
The cross-flow cylinder heads are made of aluminum with two spark plugs and two valves per cylinder. The combustion chambers of the new HEMI generation differ from those of the earlier ones. Chrysler used a flatter design with a tapered squish on both sides to achieve higher efficiency and reduce output emissions.
The camshafts actuate both the intake and exhaust valves by pushrods via rocker arms. The engine also features roller-style hydraulic tappets and beehive valve springs.
The multi-displacement system (MDS) cylinder deactivation system was integrated into the gas variant of the 5.7 HEMI. This system minimizes fuel consumption and emissions.
The system controls the flow of oil through the tappets of the corresponding valves, cutting off the fuel supply in four cylinders (two for each bank) by keeping the intake and exhaust valves closed. The intake manifold is made of plastic and drive-by-wire throttle body.
The initial engine version produced 345 hp with 375 lb-ft of torque, but a lower 340 hp with 390 lb-ft of torque for the Magnum R/T and 300C.
Applications of the 5.7 liter HEMI engine:
- 2003 - Presented Ram Pickup
- 2004 – 2009, 2011 – Today Dodge Durango
- 2005 – 2008 Dodge Magnum R/T
- 2005 – Present Chrysler 300C, 300S V8 (since 2012)
- 2005 - Present Jeep Grand Cherokee
- 2006 – Heute Dodge Charger R/T
- 2006 – 2010 Jeep Commander
- 2007 – 2009 Chrysler Espe
- 2009 - Present Dodge Challenger R/T
- 2022 - Today Jeep Wagoneer
However, in 2009, Chrysler released a revised 5.7-liter Hemi engine, also known as the 5.7 Eagle. Significant changes have been made to this machine to improve the efficiency, reliability and overall stability of this large engine.
The use of Variable Cam Timing or VCT is the most significant change, requiring an extended front cam bearing and three additional oil passages in the block.
The VCT also uses an oil control valve to control the flow of oil going to the unique camshaft sprocket, which features phasing.
A new crankshaft comes with the redesigned cylinder block, a dual-mass crankshaft damper, new pistons with a narrower ring and reinforced connecting rods.
The cylinder heads were also significantly changed. Compared to the first version, it has better airflow due to larger and almost square intake ports, 14% more air than the previous rectangular ones.
The intake valves are larger - a higher roof due to the D-shaped exhaust ports and a compression ratio increased to 10.5.
While the intake manifold has been redesigned on all HEMI vehicles, it is model specific. Non-hybrid Chrysler Aspens, Dodge Ram, and non-HEV Durango use an active intake manifold with a shorter runner valve to optimize power and torque.
The valve is closed at lower engine speeds, resulting in better low-end torque in contrast to longer runners. Meanwhile, at higher engine speeds, the valve is open and diverts the incoming air to the center of the manifold.
All heavy duty trucks and six speed manual transmission applications are different in that they do not have a multiple displacement system.
Ratings of 5.7 HEMI vehicles:
- 300C/300S V8: 363 PS und 394 lb-ft
- Charger R/T: 370 hp and 395 lb-ft
- Challenger R/T Automatic: 372 hp and 400 lb-ft
- Challenger R/T Manual: 375 hp and 410 lb-ft
- 2009 – 2012 Ram 1500 Truck: 390 PS und 407 lb-ft
- 2013 Ram 1500 Truck: 395 PS und 410 lb-ft
- Ram 2500/3500: 383 hp and 400 lb-ft
- Jeep Commander and Jeep Grand Cherokee: 360 hp and 390 lb-ft
- 2011 Dodge Durango: 360 PS und 390 lb-ft
- Dodge Durango Non-HEV and 2009 Chrysler Aspen: 376 hp and 401 lb-ft
- Dodge Durango HEV and 2009 Chrysler Aspen: 399 hp and 390 lb-ft
- 2022 Jeep Wagoneer: 392 PS und 404 lb-ft
Engine tuning, upgrades and modifications
Getting more power out of a 5.7 HEMI takes effort and the right elements to build your desired machine. Despite being an old engine, the power ratings can still be increased over the years with its proven reliability.
The first thing you do when upgrading the 5.7 HEMI is unlock the PCM. This allows the tuners to tune the vehicle the way you want it.
Next, a high-performance exhaust with dual high-flow catalytic converters is integrated into an X-pipe that has an easier time producing more horsepower since there aren't as many restrictions as the stocks.
Along with replacing the exhaust, you also need to replace the intake to allow more air to flow at higher RPMs. a larger throttle body that replaces the downpipe, heavy-duty air cleaner and a throttle body spacer.
You can also put a Hellcat Supercharger on the HEMI 5.7 but you will need an adapter kit.
Issues related to the HEMI 5.7 liter engine:
The Chrysler 5.7-liter HEMI is an extremely reliable engine and has no major design flaws. Chrysler used this 5.78-liter engine in its flagship cars and trucks for about two decades, so there's no question that these machines are as good as they sound.
But there is no such thing as a perfect engine, and at some point you may run into problems. Here are some concerns that may arise with the 5.7 HEMI:
The most common problem, not just with the HEMI but with most motors, is the motor tick problem. 345 HEMI owners have different views on this issue; Some say this is normal while others have given up and replaced their engines.
But what are the actual causes?
This is due to defective lifters and lifter rollers; They must be the major cause of engine ticking in 5.7 HEMIs. It's prevalent in 2009 models, leading some to believe that the multiple shift is to blame, which isn't valid.
The problems are most likely due to insufficient oil flow to the lift rollers, causing seizure.
The lifters touch the lobes, resulting in ticking noises. If left unattended, it can seriously damage the engine, requiring camshaft replacement, as well as the presence of metal filings in the oil.
The 5.7 HEMI uses 16 spark plugs, and considering spark plugs are standard maintenance items, replacing them regularly can save you from misfire problems.
Again, 16 spark plugs is a lot to deal with, it only takes one spark plug to fail and you know what it is. Spark plug failures are not common, but they should be changed every 30,000-40,000 miles on the 5.7 HEMI.
And last but not least, broken exhaust manifolds on the engine. This has to be the number one common problem for the 5.7 HEMI. Many owners have encountered this problem several times.
The manifold screw on the passenger side is the first to give way, probably due to a higher temperature at this point. This is because the manifold will warp backwards causing the bolts to fail.
This can also be the cause of ticking noise and exhaust leaks.
Summary
The 5.7 HEMI is a fun engine. Highly reliable, durable and well-designed pushrod motor capable of raising the reputation of big machines to a higher level. However, it's not the best engine that can be built, but certainly a lot better than competition-level engines.
With proper care and maintenance, the 5.7 HEMI can last up to 250,000 - 300,000 miles. While there are some significant issues as mentioned above, stick to the usual routine and schedule.