5.7L HEMI V8 engine (EZD: 2009-on)

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Introduction

Chrysler’s EZD engine was a member of the 5.7L HEMI V8 engine family that was produced from 2009 and powered vehicles such as the Chrysler LX 300C, Jeep WH Grand Cherokee and Jeep WK2 Grand Cherokee. Made at Chrysler’s Saltillo Engine plant in Ramos Arizpe, Mexico, key features of the 5.7L HEMI V8 engine included its:

• Deep-skirt, grey cast-iron block with a 90-degree ‘V’ and open-deck design;
• Nodular cast iron crankshaft;
• Mahle cast eutectic alloy pistons with domed crowns;
• Cast aluminium alloy cylinder head;
• 2 valves per cylinder actuated by pushrods;
• Multi-Displacement System for cylinder deactivation;
• Compression ratio of 9.6:1;
• Two spark plugs per cylinder; and,
• Maximum engine speed of 5800 rpm (electronically limited).

The EZB engine had a mass of 242 kg.

Compared to the 5.7L EZB HEMI V8 engine (produced from 2003-09), changes for the post-2009 EZD engine included:

• Stronger crankshaft with dual-mass damper;
• Floating pin pistons;
• Increased cylinder head, intake and exhaust flow (including larger intake valves);
• Variable valve timing with hydraulic cam phasing;
• New valve springs;
• A higher oil pump capacity; and,
• A higher compression ratio (10.5:1, previously 9.6:1).

While some versions of the EZD engine had an active intake manifold which could switch between short and long intake runners, it is understood that passenger cars and Jeep vehicles had a passive intake manifold.

For simplicity, this article will refer to the EZD engine as the post-2009 5.7L HEMI V8 engine.
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Block

The 5.7L HEMI V8 engine had a deep-skirt, grey cast-iron block (53021319AC/AG/CB casting) with an open-deck design that required large deck surface openings for easy sand removal after casting since the block did not have core plugs (to prevent coolant leaks). The 5.7L HEMI V8 engine had 99.5 mm bores spaced at 113.3 mm intervals and a 90.9 mm stroke for a capacity of 5654 cc. The cylinder banks formed a 90 degree ‘V’ angle and had a 22.4 mm offset.

The front cover of the 5.7L HEMI V8 engine was made from die-cast A380 aluminium and sealed the front of the block and sump; the alternator, water pump, air-conditioning compressor, power steering pump and belt idler were all mounted on the cover. The HEMI V8 engine was 523 mm long and had a deck height of 235 mm.

Crankshaft

The crankshaft for the post-2009 5.7L HEMI V8 engine was cast from nodular iron (53021300AA casting), but is understood to have benefited from ‘structural upgrades’ relative to its pre-2009 predecessor. The crankshaft was supported by five main bearings, each of which had four bolts (two vertical and two horizontal). Furthermore, the main bearing caps were made from powder metal and used cross-bolting with a single M8 bolt each side.

For the 5.7L HEMI V8 engine, the crankshaft had three bolt holes in a circular pattern for the crank sensor that was located behind the last counterweight. However, Chrysler did not supply crank sensors separately because the crankshaft was balanced with the sensor on it and Chrysler claimed that balance would be adversely affected if the crank sensor was changed. Owners therefore had to purchase a new crankshaft (with sensor) if the original sensor failed.

The main crankshaft journals had a 65 mm diameter, while the small-end journals had a 54 mm diameter. Furthermore, the 5.7L HEMI V8 engine had a dual-mass crankshaft damper.

Connecting rods

For the 5.7L HEMI V8 engine, the connecting rods were manufactured from powdered metal and had cracked big-ends. Each connecting rod was 158.5 mm long and had a mass of 597 grams +/- 5 grams (including the bolts). 

Pistons

The 5.7L HEMI V8 engine had cast aluminium pistons and are understood to have a graphite-based coating to reduce friction. For the post-2009 5.7L HEMI V8 engine, floating pin pistons were introduced, while the piston/connecting rod assembly had thinner walls and a stronger alloy pin. 

Cylinder head

The cylinder heads for the 5.7L HEMI V8 engine were cast from A319F aluminium alloy and each had a mass of approximately 13.6 kg (per cylinder bank). The cylinder heads were mounted on a three-layer stainless steel gasket – which had a compressed thickness of 0.7 mm – and bolted to the block using M12 bolts around the bores and M8 bolts near the intake manifold. For the post-2009 5.7L HEMI V8 engine, the cylinder heads were revised for increased air flow.

Camshaft, pushrods and valves

For the 5.7L HEMI V8 engine, the camshaft was positioned high in the cylinder block to minimise the length of the pushrods, though shorter pushrods were used for the intake valves relative to the exhaust valves. To minimise side loading on the roller-style valve lifters, the cam had oversized journals and lobes.

The 5.7L HEMI V8 engine had two valves per cylinder with eight deactivating and eight conventional hydraulic lifters, all with roller followers. Specifications for the valves were as follows –

• Intake valve diameter (head): 52.8 mm (compared to 50.8 for the pre-2009 5.7L HEMI V8 engine);
• Exhaust valve diameter (head): 39.4 mm;
• Intake valve lift: 12.0 mm;
• Exhaust valve lift: 11.7 mm; and,
• Included valve angle: 34.5 degrees.

Furthermore, the valve seats and valve guides were made from powdered metal.

The lifters were oiled via the pushrods whereby oil circulated:

• From the pump to the cam bearings; then,
• Up through the cylinder heads to the rocker shafts; and then,
• Through the rockers and down the pushrods to the lifters.

As a result, the oil passages in the valley of the engine block could be used to deactivate the MDS lifters. Furthermore, the pushrods provided a reservoir of oil to prevent lifter noise at start up.

The post-2009 5.7L HEMI V8 engine introduced new valve springs, though they are understood to be beehive-type springs like its predecessor.

Multi-Displacement System (MDS)

The 5.7L HEMI V8 engine had a ‘Multi-Displacement System’ (MDS) which enabled the engine to switch from eight to four cylinder operation. The MDS system used a separate oil gallery in the valley of the block and four solenoids to apply pressure to the pins in the sides of the deactivating valve lifters in cylinders 1, 4, 6 and 7. Furthermore, the fuel injectors were shut off.

When disabled, the lifter body continued to go up and down, but the plunger inside the lifter remained stationary so that the valves stayed closed. The exhaust gases trapped in each cylinder were compressed on the compression and exhaust strokes so that they helped push the pistons back down on the intake and power strokes. The ECU could activate and deactivate the MDS solenoids in 40 milliseconds.

Variable camshaft timing

Significantly, the post-2009 5.7L HEMI V8 engine introduced variable camshaft timing via an Oil Control Valve (OCV), an electro-hydraulic pulse width modulated solenoid that was attached to the cylinder block behind the timing cover. The OCV controlled oil pressure to a camshaft phaser which was contained in the camshaft sprocket.

The camshaft phaser had internal vanes and the OCV regulated oil flow to either side of the vanes so that the phaser could rotate and change the position of the camshaft. Since valve timing was in advanced position by default, the OCV values operated as follows:

• If the OCV was 0%, valve timing was advanced (default position);
• If the OCV was at 100%, valve timing was retarded; and,
• If the OCV was at 50%, there was no oil flow and valve timing was held constant.

Variable camshaft timing could improve fuel economy by:

• Reducing the engine’s pumping work by closing the intake valve later;
• Increasing the expansion process of the combustion event – this allowed more work to be transferred to the crankshaft instead of being removed from the exhaust port as heat; and,
• Expanding the operating range of the Multi-Displacement System.

For the related 6.4L HEMI V8 engine, the camshaft could be varied by up to 37 degrees to retard the inlet and exhaust simultaneously; it is expected that this range of adjustment is shared with the post-2009 5.7L HEMI V8 engine.

Intake

The intake manifold assembly (‘Integrated Air Fuel Module”) was made from a plastic composite (Nylon 6) and contained the injectors, an 80 mm diameter electronic throttle butterfly, an intake manifold, sound-damping cover, the PCV system, MAP sensor and engine wiring harness.

For the post-2009 5.7L HEMI V8 engine, the intake and exhaust ports were redesigned. While an active intake manifold (i.e. switchable long runners for low-end torque and short runners for high-rpm power) was available for some models, it is understood that this did not include passenger vehicles or Jeep models.

Injection and ignition

According the Chrysler, the 5.7L HEMI V8 engine had hemispherical combustion chambers for large valves, high air flow and so that the spark plugs could be positioned close to the centre of the combustion chamber. However, the chambers were not truly hemispherical since there were squish areas on both sides of the combustion chamber.

The 5.7L HEMI V8 engine had electronically-controlled, sequential multi-port fuel injection and a compression ratio of 10.5:1 (compared to 9.6:1 for the pre-2009 5.7L EZB HEMI V8 engine). The HEMI V8 engine had distributorless, coil over plug ignition via two spark plugs per cylinder – according to Chrysler, the two spark plug design shortened flame travel for more consistent combustion and reduced emissions. To reduce the likelihood of leaks, the spark plugs were mounted in cast-in towers.

Lubrication

The 5.7L HEMI V8 engine had a gerotor oil pump that was driven from the timing chain crankshaft sprocket. The oil pump housing was made from die-cast aluminium, the gerotors from powdered metal and the cover plate from cast iron. For the post-2009 5.7L HEMI V8 engine, the oil pump had a higher flow rate.

Exhaust

The exhaust manifolds for the 5.7L HEMI V8 engine were cast from high silicon-molybdenum ductile iron and designed to satisfy the following objectives:

• Compact dimensions;
• High flow capacity;
• Low thermal inertia for fast warm-up of the catalytic converters; and,
• To protect under-bonnet components from heat.

For the post-2009 5.7L HEMI V8 engine, a freer-flowing exhaust system was introduced.