A Closer Look At GM’s 4.3L LV3 V6

gm-4-3l-v6-ecotec3-lv3-engine-2Back in the mid-1980s, General Motors released a small, reliable, torquey, and somewhat powerful 4.3L V6 version of its small-block V8 as an economical and cost-effective solution to utilitarian vehicles.

Being installed in a varying array of vehicles, from the S10 to the full-sized pickups and even the ’80s-era Caprices and Monte Carlos, the small-block V8, minus two cylinders, would find a home in millions of vehicles worldwide. The 4.3L six-shooter even had a stint as the turbocharged mill that powered the GMC Syclone and Typhoon in the ’90s.

It was one of the longest-running production V6s in American history, until recently, when it was finally killed off. Not because the 4.3L was a bad engine, it wasn’t. It was just outdated in terms of technology and efficiency. Think about it, a 4.3L V6 with 190 hp doesn’t make sense in a world filled with 3.6L V6’s packing well over 300 hp. It was time for a serious overhaul.

Now here we are, gearing up for 2015, and Chevrolet finally has a suitable replacement for old faithful. It has a displacement of, are you ready? Four-point three liters, or 262 cubic inches. The exact displacement as the original. Now before you go thinking it’s the same old engine with new technology, let me stop you right there.

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The 4.3L LV3 V6 offers 285 hp and 305 lb-ft. of torque, with VVT and direct-injection. No turbo needed.

Much in the same way the original 4.3L V6 was a Gen-I V8 with two cylinders lopped off, the LV3 V6 is based on the new Gen-V V8 architecture – which is the same platform as the brand new LT1/LT4 found in the C7 Corvettes, and 5.3L/6.2L variants found in the 2014-2015 full-sized trucks.

Oh, and in case you’re playing catch-up, the Gen-V V8 is an entirely different architecture than the Gen-III/Gen-IV LS-based V8s. That’s right, the LS-series days are numbered at GM in terms of a production vehicle standpoint. Once the 5th-Gen Camaro goes out of production after the 2015 model year, and the Chevy SS sedan gets a reboot for 2017, there will no longer be any LS-powered vehicles coming from GM.

This is an entirely new block. Actually, everything is all new from the bottom up, at least compared to the original 4.3L antique it replaces. The changes are so immense that we decided to give you a complete rundown of the specs to show you the sort of hardware this thing is packing. With 285 hp and 305 lb-ft. rated at the crank, we just can’t wait to get our hands on one!

 

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Engine Block:

  • aluminum
  • 90-degree cylinder angle
  • 4.400-inch bore centers

Bore and Stroke Dimensions:

  • 3.92-inch bore x 3.62-inch stroke (262 ci./4.3L)
  • engineered for engine-driven fuel pump and vacuum pump
  • improved sealing and oil-spray piston cooling
  • new engine mount attachments
  • new knock sensor locations

Oiling System:

  • variable-displacement vane pump (with increased flow capacity) –  enables the pump to efficiently deliver oil pump flow as demanded
  • dual-pressure control enables operation at efficient oil pressure and at lower RPM coordinated with the AFM
  • six-quart aluminum oil pan
  • Dexos semi-synthetic 5w30 oil

Oil-Spray Piston Cooling:

  • (8) oil-spraying jets in the engine block coat underside of each piston and surrounding cylinder walls with extra layer of friction-reducing oil.
  • reduces piston temperature, promoting extreme output and long-term durability
  • dampens piston noise (or piston slap)

Rotating Assembly:

  • steel crankshaft
  • nodular main bearing caps
  • 6.125-inch powder-metal connecting rods
  • high-strength, lightweight aluminum-alloy pistons

Windage Tray:

  • features new “oil scraper” design; enhances performance and efficiency by improving oil flow control and bay-to-bay crankcase breathing

 

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PCV-Integrated Rocker/Valve Covers:

  • hold direct-mount ignition coils for coil-near-plug ignition system.
  • contains baffles that separate oil and air from the crankcase gases
  • domed rocker/valve covers house an integrated (PCV) system; enhancing oil economy and oil life reduces oil consumption and lower emissions

Camshaft Design:

  • Hydraulic roller-lifter
  • Specs: 12.7/12.5mm (0.500/0.492-inch) intake/exhaust lift, 193/199-crank angle degree intake/exhaust duration at 0.050-inch tappet lift and 113-degree LSA
  • All-new “trilobe” to drive the engine-mounted, high-pressure fuel pump

Dual-Equal Cam Phasing (VVT):

  • enhances fuel economy
  • maximizes engine performance
  • dual-equal cam phasing system adjusts camshaft timing at same rate for both intake and exhaust valves
  • allows smooth, near-peak levels of torque over a broad rpm range,
  • allows high specific-output without sacrificing overall engine response or driveability
  • provides effective tool for controlling exhaust emissions

Cylinder Head:

  • aluminum
  • 59.18cc combustion chamber
  • 11.0:1 compression ratio
  • new port opening locations at manifold face
  • rectangular intake ports with “slight twist” enhances mixture motion
  • supports high airflow at higher RPM for a broad horsepower band and low-RPM torque
  • new spark plug angle and depth protrude further into the chamber – places the electrode closer to the center of combustion
  • exhaust port shapes are optimized for new valve locations
  • lightweight  1.93-inch intake and 1.56-inch exhaust valves- enables engine to rev quickly over 6000 rpm
  • 12.6-degree intake/12.1-degree exhaust valve angles
  • double valvesprings
  • 1.8:1 ratio roller-pivot rocker arms
  • 8.7mm (outside diameter) pushrods

Direct Injection:  

  • moves the point where fuel feeds into an engine closer to the point where it ignites – enables greater combustion efficiency
  • provides a more complete burn of the fuel in the air-fuel mixture
  •  operates at lower temperature than conventional port injection – allows mixture to lean
  • dished head pistons direct fuel spray for more complete combustion

High-Pressure Fuel Pump:

  • high fuel pressure in-tank pump – up to 15Mpa (150bar),
  • high-pressure, camshaft-driven,secondary  fuel pump  mounted in the engine valley
  • “soft stop” control for pump’s internal solenoid significantly reduces the “ticking” sound typical of direct injection systems

Expanded Active Fuel Management Operation:

  • deactivates two cylinders under light load conditions
  • expands range of operation by more than 10-percent over predecessor
  • dual-mode oil pump enables AFM quicker than Gen-IV applications helping enhance fuel economy better than ever before

Exhaust Manifolds:

  • developed to improve durability, sealing and reduce operation noise
  • cast iron for durability and excellent heat-managing properties.

High-Flow Intake Manifold:

  • port-matched to cylinder head
  • composite design manufactured with lost-core process; improves runner-to-runner variation and reduces flow loss
  • accommodates high-pressure fuel pump for DI system
  • features acoustic foam to reduce engine and fuel pump noise

Electric Throttle Body:

  • single-bore, 72mm contact-less design
  • offers more durability and enables greater control

Cooling System:  

  • new offset water pump and thermostat

Ignition System:

  • 58X crankshaft position encoder ensures ignition timing is accurate throughout its operating range
  • more consistent engine starting
  • crankshaft ring and sensor provide more immediate and accurate information on the crankshaft’s position during rotation
  • allows engine control module to adjust ignition timing with greater accuracy – optimizes performance and economy

Additional New Features:

E92 ECU:

  • all new for Gen-V 

E85 Capable: 

  • able to run on E85 ethanol, gasoline, or any combination of the two fuels

Coil-on-Plug Ignition:

  • individual coil over plug; mounted on valve/rocker covers – delivers maximum voltage and consistent spark density, with no variation between cylinders

Spark Plugs:

  • iridium electrode tip and an iridium core in the conductor, offers higher internal resistance while maintaining optimal spark density

Electronic Power Steering:

  • does not incorporate a conventional, hydraulic power steering in accessory-drive system; enhances both performance and fuel efficiency

Vacuum Pump:

  • engine-driven mechanical; enhances braking performance

 

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