LT5 Engine Specifications

Legal and Emissions Information

Federal law restricts the removal of any part of a federally required emission control system on motor vehicles. Further, many states have enacted laws which prohibit tampering with or modifying any required emission or noise control system. Vehicles which are not operated on public highways are generally exempt from most regulations, as are some special interest and pre-emission vehicles. The reader is strongly urged to check all applicable local and state laws. Many of the parts described or listed in this manual are merchandised for off-highway application only, and are tagged with the "Special Parts Notice" reproduced here:

Special Parts Notice

This part has been specifically designed for Off-Highway application only. Since the installation of this part may either impair your vehicle's emission control performance or be uncertified under current Motor Vehicle Safety Standards, it should not be installed in a vehicle used on any street or highway. Additionally, any such application could adversely affect the warranty coverage of such an on-street or highway vehicle.

Kit Content

• LT5 ENGINE (DRY OIL SUMP)
• CAP-OIL FILL
• INSTRUCTION SHEETS
• PUMP-COOLANT

Oil fill cap: Install the oil fill cap by twisting clockwise while pushing inward.

Diagram description: Image showing the location of the oil fill cap on the engine.

Intercooler coolant pump: The LT5 kit is supplied with a supercharger intercooler pump. A custom liquid to air intercooler must be incorporated within the vehicle to reduce the charge air temperature. If purchasing the Chevrolet Performance Parts (CPP) engine controller, it will have an electrical connector designed to fit the supplied pump. The CPP controller will run the pump when cooling is required.

Diagram description: Image showing the intercooler coolant pump with labeled "Pump Outlet" and "Pump Inlet".

Intercooler plumbing: Images show the connections for the intercooler system, including left side cooler outlet and inlet.

Ignition System

The Gen-V has an advanced 58X crankshaft position encoder to ensure that ignition timing is accurate throughout its operating range. The 58X crankshaft ring and sensor provide more immediate, accurate information on the crankshaft's position during rotation. This allows the ECM to adjust ignition timing with greater precision, which optimizes performance and economy. Engine starting is also more consistent in all operating conditions. In conjunction with 58X crankshaft timing, the Gen-V applies the latest digital cam-timing technology. The cam sensor is located in the front engine cover, and it reads a 4X sensor target on the camshaft phaser rotor which is attached to the front end of the camshaft. The target ring has four equally spaced segments that communicate the camshaft's position more quickly and accurately than previous systems with a single segment. The dual 58X/4X measurement ensures extremely accurate timing for the life of the engine. Moreover, it provides an effective backup system in the event one sensor fails.

• Air Induction Humidity Sensor: This new feature ensures optimal combustion efficiency, regardless of the surrounding air's humidity.
• Coil-on-Plug Ignition: The Gen-V's individual coil-near-plug ignition features advanced coils that are compact and mounted on the rocker covers, although they are positioned differently than on Gen-IV engine. An individual coil for each spark plug delivers maximum voltage and consistent spark density, with no variation between cylinders.
• Iridium-Tip Spark Plugs: The spark plugs have an iridium electrode tip and an iridium core in the conductor, offering higher internal resistance while maintaining optimal spark density over its useful life. The electrode design improves combustion efficiency.

Fuel System

Low Pressure (Fuel Tank to Engine)

The production system uses a returnless variable flow/pressure system that has been incorporated in the Chevrolet Performance engine control kit. A returnless fuel system reduces the internal temperature of the fuel tank by controlling the speed of the fuel pump and not returning hot fuel from the engine to the fuel tank. If using the Chevrolet Performance engine control kit, a pulse width modulation capable fuel pump that delivers 500 kPa (72psi) at 45 gallons per hour is required. If not using the Chevrolet Performance engine control system, then a fuel pump and a regulator that delivers 500kPa (72psi) with 45 gallons per hour of flow must be used.

High Pressure (On Engine)

The LT5 engine is equipped with two sets of fuel injectors. The (8) DI/primary fuel system consists of 8 separate direct injection fuel injectors, two high pressure fuel rails, a high pressure cross-over fuel pipe (connects the two fuel rails), a high pressure fuel feed pipe (connects the cross-over pipe to the high pressure fuel pump), a high pressure fuel pump and a low pressure fuel feed pipe. The injectors are each seated into their individual bores in the cylinder heads with two combustion seals to provide sealing. The high pressure fuel pump mounts to the rear of the Engine Block Valley Cover in the engine valley. Motion is transmitted to the pump from a tri-lobe on the rear of the camshaft through a hydraulic roller lifter.

A second set of (8) PFI/secondary fuel injectors are mounted to the Supercharger assembly. The PFI/secondary fuel injectors are present to supplement fuel delivered to the engine when the DI/primary fuel system is not capable of providing the total engine fueling demand. The PFI/secondary fuel injectors are only activated at high engine loads when substantial fuel enrichment is necessary for exhaust system protection or to achieve peak engine torque/power.

The high fuel pressure necessary for direct injection is supplied by the high pressure fuel pump. The high pressure fuel pump is mounted on the rear of the engine under the intake supercharger manifold and is driven by a three-lobe cam on the camshaft. This high pressure fuel pump also regulates the fuel pressure using an actuator in the form of an internal solenoid-controlled valve that is controlled by the ECM.

Crankcase Ventilation System Description (LT5)

A positive crankcase ventilation (PCV) system is used in order to provide a more complete scavenging of crankcase vapors. Filtered air from the air induction system duct is supplied to the crankcase, mixed with blow-by vapors, and passes through a crankcase ventilation metering device before entering the supercharger. The primary component in the positive crankcase ventilation (PCV) system is the PCV flow metering device (valve or orifice). Vacuum changes within the supercharger result in flow variations of the blow-by vapors. If abnormal operating conditions occur, the design of the PCV system permits excessive amounts of blow-by vapors to back flow through the crankcase vent tube and into the engine induction system to be consumed during normal combustion. This engine ventilation system design minimizes oil consumption and significantly reduces the potential for oil ingestion during vehicle limit handling maneuvers. There are two clean air supply locations for PCV. One on the right side valve cover and one on the left side valve cover. See Figure 1

The LT5 engine utilizes an integral positive crankcase ventilation system which is located in the Engine Block Valley Cover beneath the Supercharger Assembly. The Engine Block Valley Cover contains composite oil separating baffles and PCV plumbing. Filtered fresh air is routed from upstream of the throttle plate to the engine oil tank where it mixes with crankcase gasses and is passed to both engine rocker arm covers. The rocker arm covers' design shields rocker arm oil spray, thereby reducing the potential for oil being drawn back into the tank during backflow of the ventilation system. Blow-by vapors are routed from the Engine Block Valley Cover through a fixed orifice 7.5 mm (0.295 in) within a steel PCV tube, then into the underside of the supercharger near the front of the engine block valley cover.

Diagram description: Image shows the engine valve cover with a "Filtered air inlet" and PCV hose routing.

Vacuum Port: This port needs to be capped or can be used to supply vacuum to the brake booster.

Diagram description: Image shows the vacuum port on the engine intake manifold.

Variable Camshaft Timing

This engine has the ability to vary the camshaft position versus the piston position. If you chose to use the Chevrolet Performance engine controller kit, then it will vary camshaft timing to improve emission and fuel economy, while still producing great power. At idle, for example, the cam is at the full advanced position, allowing exceptionally smooth idling. Under other conditions, the phaser adjusts to deliver optimal valve timing for performance, drivability and fuel economy. At high rpm it may retard timing to maximize airflow through the engine and increase horsepower. At low rpm it can advance timing to increase torque. Under a light load, it can retard timing at all engine speeds to improve fuel economy. A vane-type phaser is installed on the front of the camshaft to change its angular orientation relative to the sprocket, thereby adjusting the timing of valve operation on the fly. It is a dual-equal cam phasing system that adjusts camshaft timing at the same rate for both intake and exhaust valves. The system allows linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response, or drivability. It also provides another effective tool for controlling exhaust emissions.

Intake Manifold/Supercharger Assembly

The LT5 Roots-type supercharger is a positive displacement pump that consists of 2 counter-rotating rotors installed into the lower intake manifold housing. The rotors are designed with 4 lobes and a helical twist. The rotors of the supercharger are designed to run at a minimal clearance, not in contact with each other or the housing and are timed to each other by a pair of precision spur gears which are pressed onto the rotor shafts. The rotors are supported at each end by self-lubricating non-serviceable bearings. The drive belt pulley is pressed onto the input shaft. The input shaft is coupled to the rotor shaft. Both the belt pulley and shaft coupling are also non-serviceable.

The upper intake manifold housing has an integrated intercooler system. Cooling the air enhances the effectiveness of the supercharger. The intercooler uses conventional coolant in a separate system from the engine cooling system. The intercooler system includes two charge air coolers/heat exchangers, a water manifold assembly, and a variety of sensors to monitor air temperature and pressure. The water manifold, located at the front of cover transfers coolant to the cover via four internal transfer tubes. The transfer tubes and water manifold are sealed with O-rings and press-in-place seals. Coolant enters the inlet port of the water manifold assembly, is directed into and through the two charge air coolers/heat exchangers, and exits back into the water manifold. Coolant then exits the water manifold outlet port returning to the separate cooling system. The two charge air coolers/ heat exchangers are not serviceable.

The supercharger assembly consists of the following components:

• Lower Intake Manifold Housing, to include rotors, gears, bearings, shaft coupling, and drive belt pulley
• Electronic compressor recirculation valve
• Bypass Actuator
• Throttle Body Assembly
• Evaporative Emission Canister Purge Valve
• Inlet Pressure Sensor
• Manifold Air Pressure and Temperature Sensor
• Over boost Control
• Water Manifold Assembly
• Charge Air Coolers/Heat Exchangers
• Intake Air Temperature (IAT) Sensor
• Air Outlet Pressure Sensor

Operation

The supercharger is designed to increase the air pressure and density in the intake manifold. When this air is mixed with the correct amount of fuel the result is more power from the engine. The supercharger provides an intake manifold air pressure of up to 65.8 kPa (13.9 psi). The supercharger is a positive displacement pump and is directly driven from the engine drive belt system, an increase in intake manifold air pressure is available at all engine speeds.

The charge air bypass valve is an electrically operated valve that is attached to the supercharger housing. The valve is controlled by the engine control module (ECM). The ECM determines when pressure from the manifold is routed to the bypass actuator. The charge air bypass valve allows pressure from the manifold to open the bypass valve and lower boost pressure during specific driving conditions. The open bypass valve reduces the pumping effort of the supercharger, thereby increasing the fuel efficiency in light load operations.

Powertrain Cooling

Coolant Type

40/60 coolant/water mixture of clean, drinkable water and use only DEX-COOL® Coolant.

Engine Cooling System

A surge tank is recommended for removing air from the engine coolant, but as long as the radiator or surge tank is the highest point in the system, then air will be evacuated from the coolant. The highest point, meaning that either the radiator or the surge tank have a portion higher than the top of the cylinder heads. If they are not, then air can be trapped within the cylinder heads and cause portions of the cylinder heads to overheat, which will be detrimental to engine performance and longevity. Coolant is drawn from the radiator outlet and into the water pump inlet by the water pump. Some coolant will then be pumped from the water pump, to the heater core, then back to the water pump. This provides the passenger compartment with heat and defrost. Coolant is also pumped through the water pump outlet and into the engine block. In the engine block, the coolant circulates through the water jackets surrounding the cylinders where it absorbs heat.

The cylinder head air bleed needs to be routed to the highest point in the cooling system. This will assist in removing air from the cylinder heads.

Diagram description: Image shows the engine with "Pump Outlet", "Pump Inlet", and "Cylinder Head Air Bleed" labeled.

Hose 84214922 can be purchased to obtain the heater inlet/outlet quick connects, when creating a custom installation.

Diagram description: Image shows the "Heater inlet/outlet" connections.

Engine Oil Pump - Dry Sump Oiling

Engine lubrication is supplied by a two-stage oil pump assembly. The oil pump assembly consists of a primary vane-type variable displacement pump and a secondary geroter-style pump. The primary pump contains a pressure relief valve that protects the oil pan mounted oil filter from over pressurization during cold engine start up. If system pressure exceeds 600 kPa (87 psi), the pressure relief valve will open and exhaust oil back into the oil pan. The front or forward gear set is the secondary pump. The rear or rearward housing contains the primary pump. The pump assembly is mounted at the front of the engine and driven directly by the crankshaft sprocket. The vanes of the primary pump rotate clockwise and draw oil from the engine oil tank through the oil tank screen. The oil is pressurized as it passes through the primary pump and is sent through the engine block lower oil gallery.

Pressurized oil is directed through the engine block lower oil gallery to the full flow oil filter where harmful contaminants are removed. A bypass valve is incorporated into the oil filter, which permits oil flow in the event the filter becomes restricted.

Oil exits the oil filter and is then directed to the external oil cooler. The external oil cooler is a liquid to liquid (engine coolant to oil) oil cooler and consists of an oil pan mounted core and coolant lines that connect the oil cooler to the engine cooling circuit. A bypass valve is incorporated into the oil cooler assembly in the event oil flow within the cooler is restricted. Oil returns from the oil cooler and is directed to the upper engine main oil galleries.

The LT5 Gen-V engine feature oil-spray piston cooling, in which eight oil-spraying jets in the engine block drench the underside of each piston and the surrounding cylinder wall with an extra layer of cooling, friction-reducing oil. The oil spray reduces piston temperature, promoting extreme output and long-term durability. The extra layer of oil on the cylinder walls and wristpin also dampens noise originating from the pistons.

The oil tank inlet port is used to supply scavenged oil from the engine to the storage tank. The oil tank outlet port is used to supply non-aerated oil from the storage tank to the engine. Chevrolet Performance parts oil adaptor kit part number 25534412 can be used to convert to AN-12 fittings, when using specialized reservoir tank.

When replacing engine oil, there are two oil drain plugs within the oil pan. One plug drains the oil pan and the other plug drains the storage tank.

Diagram description: Image shows the oil drain plugs on the oil pan.

Engine Oil Cooling

The engine as delivered comes with a liquid to liquid engine oil cooler. Engine oil is pumped thru the cooler and engine coolant is pumped thru the cooler, to transfer the engine oil heat into the engine coolant. The engine coolant should route to the lower portion of the radiator, or inlet hose of the coolant pump. Heat is then removed by the engine radiator.

Diagram description: Image shows the engine with "Oil cooler hose 1" and "Oil cooler hose 2" labeled.

If the cooler is not used then the following parts can be used to eliminate the oil cooler.

Diagram description: Image shows a "Coolant Plug", "Oil transfer plate", and "Oil Cooler bolts".

Pilot Bearing

You must install a pilot bearing in the rear of the crankshaft, if the engine will be used with a manual transmission. The pilot bearing aligns the transmission input shaft with the crankshaft centerline. A worn or misaligned pilot bearing can cause shifting problems and rapid clutch wear. There are two different Chevrolet pilot bearings for the LT5, 14061685 is for a long input shaft transmission and 12557583 is for a short input shaft transmission. Verify fit prior to installing the transmission or damage will occur.

Starter Motor

A starter motor is not provided with the engine. The following parts are designed for the LT5 starting system.

Diagram description: Image shows the "Starter Motor" and "Heat shield".

Evaporative Emissions Valve

The evaporative emissions system can be used with the Chevrolet Performance engine control kit, but is not required for proper engine operation. This port should be plugged or connected to a vapor canister.

Exhaust Manifolds

The as shipped exhaust manifolds may not fit your vehicle. One option is to use the Chevrolet Silverado Gen 5 small block manifolds or Chevrolet Camaro Gen 5 small block manifolds.

Charge Air Cooling System (LT5)

This kit contains a charge air coolant pump. The pump is controlled by the Chevrolet Performance Parts engine control system. The charge air cooling systems function is to reduce the temperature of the air charge that is heated during the supercharging process which improves the efficiency and performance of the powertrain. The charge air cooling system is an air-to-coolant system that uses a separate charge air cooling radiator. An electric pump is used to flow coolant from the charge air cooler (vehicle specific), through the supercharger, then back to the charge air cooler where the cycle repeats.

OIL PRIMING

Safety first: If the vehicle is on the ground, be sure the park brake is set, the wheels are chocked and the car cannot fall into gear. Verify everything is installed properly and nothing was missed.

After installing the engine, ensure the oil system has been filled. The engine will come with some oil. Due to the custom nature of a dry sump oiling system, it is up to the customer to determine the correct amount of oil.

This crate engine requires a special oil meeting DEXOS1 - 0W40 or Mobil 1 15W50. Also, check and fill as required any other necessary fluids such as coolant, power steering fluid, etc.

Preluber instructions (Kent-More J-45299):

NOTE: A constant and continuous flow of clean engine oil is required in order to properly prime the engine. Be sure to use approved engine oil, as specified.

• Install an oil pressure gauge (the existing oil pressure sensor location at the upper rear of the engine may be used).
• Locate and remove the engine block left rear oil gallery plug.
• Install the adapter M16 x 1.5 part number 509375
• Install the flexible hose to the adapter and open the valve.
• Pump the handle on the J-45299 preluber in order to flow a minimum of 1-1.9 liters (1-2 quarts) engine oil. Observe the flow of engine oil through the flexible hose and into the engine assembly. The engine will be primed after a small amount of pressure change is seen on the in car oil pressure gauge while pumping J-45299.
• Close the valve and remove the flexible hose and adapter from the engine.
• Apply approved thread sealer and Install the oil gallery plug to the engine and tighten to 60 Nm (44 lb. ft.).

Diagram description: Image shows the location for oil priming on the engine.

In the absence of a preluber kit, the following process can be used.

1. Install an oil pressure gauge (the existing oil pressure sensor location at the upper rear of the engine may be used).
2. Disconnect fuel and the ignition control system (removing power from the ignition control module is recommended).
3. Remove all of the spark plugs, which will reduce the load on the engine bearings and starter motor during the oil priming sequence.
4. Once, the fuel and ignition control systems have been disconnected, place the vehicle in neutral and crank the engine using the starter for 10 seconds and check for oil pressure. If no pressure is indicated, wait 30 seconds and crank again for 10 seconds. Repeat this process until oil pressure is indicated on the gauge.
5. Install the spark plugs and reconnect the fuel and ignition control systems.

START-UP AND BREAK-IN PROCEDURES

1. Start the engine and listen for any unusual noises. If no unusual noises are noted, run the engine at approximately 1000 RPM until normal operating temperature is reached.
2. When possible, you should always allow the engine to warm up prior to driving. It is a good practice to allow the oil sump and water temperature to reach 180°F before towing heavy loads or performing hard acceleration runs.
3. The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations.
4. Run five or six medium throttle (50%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear.
5. Run two or three hard throttle (WOT 100%) accelerations to about 4000 RPM and back to idle (0% throttle) in gear.
6. Change the oil and filter. Replace the oil and replace the filter with a new AC Delco oil filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.
7. Drive the next 500 miles (12 to 15 engine hours) under normal conditions. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load.

Change the oil and filter. Again, inspect the oil and oil filter for any foreign particles to ensure that the engine is functioning properly.

LT5 Engine Specifications

Information may vary with application. All specifications listed are based on the latest production information available at the time of printing.