Well now I'm just too curious for my own good haha.
I pulled the crank sensor and its a later version with a single o-ring at the top. Cam sensor part number is 12568983, I believe that is the 04 and up CPS.
The only other reason I think its an 05 is the 2006 model year summary lists Returnless fuel system as new for Kodiak/Topkick.
2006 model year summary
• Increase to 325 horsepower for Chevrolet Suburban, Avalanche and GMC Yukon XL
• New dual mid-coupled converter system
• Returnless fuel injection for Chevrolet Kodiak and GMC TopKick
• Improved electronic throttle control pedal and throttle actuator control (TAC) module
• Recalibrated P59 engine controller
Its an odd one for sure, lucky for me it has the best of all variants for my swap situation.
Ill definitely swap a new crank sensor before I put it together I was thinking what a nightmare that would be in the truck while looking at the motor the other day haha.
Ill also definitely think on the manifolds, I'm with you.. flat flanges suck. I would rather have a doughnut gasket any day. I swapped the guy straight across so im only out shipping for my set. Just trying to keep costs low for now, I know there are still a couple unknowns that will ultimately have to be solved with $$.
Thanks for the Centerforce number, the price is a little harsh but I don't mind paying a little if it will save me from pulling the trans sooner rather than later to swap a burnt clutch.
You’re right, somehow I missed that one in my GM Powertrain model year summary stash. Looks like 2004 was the main year for returnless in trucks, SUVs and Workhorse then Marine got it in 2005 and Medium Duty got it in 2006. The weird thing is Workhorse used the medium duty engine assembly part number so I had it in my head they all went returnless in 2004. Odd, as the big Fed EVAP change was for 2004 Model Year. Good reminder of what happened when. Good catch!
Vortec 8100 8.1L V-8 (L18)
2004 Model Year Summary
• Returnless fuel injection for Chevrolet Avalanche, Silverado and Suburban, GMC Sierra and Yukon XL and Workhorse Custom Chassis
• Low permeability intake manifold body gaskets
• Improved onboard refueling vapor recovery (ORVR) system for Avalanche, Silverado, Suburban, Sierra and Yukon XL
• Exhaust gas recirculation (EGR) eliminated
• Improved crank and cam timing sensors
• Improved crankshaft seal
• Adjustable throttle pedal for Workhorse Custom Chassis
• Revised cylinder heads for industrial applications
FULL DESCRIPTIONS OF NEW OR CHANGED FEATURES
RETURNLESS FUEL INJECTION FOR CHEVROLET AVALANCHE, SILVERADO AND SUBURBAN, GMC SIERRA AND YUKON XL AND WORKHORSE CUSTOM CHASSIS
All Vortec 8100s built for these applications are equipped with a new "returnless" fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system.
Before model year 2004, the Vortec 8100’s sequential fuel injection (SFI) used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the tank. The new system eliminates the return lines and moves the fuel-pressure regulator from the fuel rail on the engine to the fuel tank. The fuel line from the tank now includes pulse dampeners, or a series of baffles, that manage fuel pulsing and limit noise.
Because it delivers only the amount of fuel need by the injectors, and returns no fuel to the gas tank, the returnless system essentially eliminates heat transfer from the engine to tank. This reduces the amount of vapor generated in the tank, and captured by the evaporative emissions control system.
Vortec 8100s built for the medium-duty Chevrolet Kodiak and GMC Topkick, as well as those built for marine and industrial applications, continue with fuel injection managed with return lines.
LOW PERMEABILITY INTAKE MANIFOLD AND THROTTLE BODY GASKETS
The Vortec 8100 has new intake manifold sealing gaskets manufactured from a fluorocarbon material. These fluorocarbon gaskets represent the best sealing technology available. The gaskets are resistant to most chemicals, for maximum durability, and particularly impermeable to small hydrocarbon molecules. Gasoline vapor cannot penetrate the fluorocarbon. Moreover, the gaskets are designed to improve sealing for the life of the engine. They are molded with slight protrusions, or ``snouts,’’ that fit into counter-bores milled in the cylinder heads. The snouts more positively locate the gaskets and virtually eliminate the possibility of movement during assembly or after repeated thermal cycling over the life of the engine.
IMPROVED ONBOARD REFUELING VAPOR RECOVERY (ORVR) SYSTEM FOR CHEVROLET AVALANCHE AND SILVERADO, GMC SIERRA AND YUKON XL
The ORVR system on these Vortec 8100-equipped vehicles uses a new evaporative emissions canister and purge-control solenoid. ORVR reduces evaporative emissions by preventing gasoline vapor from escaping into the atmosphere during refueling. These new ORVR components take full advantage of advanced technology built into the Vortec 8100's P59 Powertrain Control Module (PCM). The PCM and new components more efficiently manage ORVR, and improve the accuracy and robustness of the OBDII (On-Board Diagnostics) system.
Vortec 8100 8.1L V-8 (L18)
2005 Model Year Summary
• New for Chevrolet Kodiak and GMC TopKick with four-wheel drive
• Floating pin pistons
• Returnless fuel injection for marine applications
• Improved oil pan (for medium duty applications)
• Improved throttle actuator control module
• Rate-based diagnostics
• GF-4 engine oil
FULL DESCRIPTIONS OF NEW OR CHANGED FEATURES
NEW FOR CHEVROLET KODIAK AND GMC TOPKICK WITH FOUR-WHEEL DRIVE
For 2005, the Vortec 8100 will be available in Chevrolet Kodiak and GMC Topkick medium-duty trucks with four-wheel drive. Vortec 8100s built for this application require packaging adjustments to accommodate a front transaxle, including exhaust manifolds, heat shields and starter motor.
FLOATING PIN PISTONS
The Vortec 8100 is fitted with new floating-pin pistons. Introduced previously on GM Powertrain’s Vortec 6000 V-8, these pistons feature wrist pins that “float” inside the rod bushing and the pin bores in the piston barrel. Previously, the Vortec 8100 used a fixed-pin assembly, in which the connecting rod is fixed to the piston’s wrist pin, and the pin rotates in the pin bore. In the Vortec 8100, snap rings now retain the wrist pin in the piston, while the rod moves laterally on a bushing around the pin.
The Vortec 8100’s pistons, piston rings and connecting rods are identical to those used in 2004. The new floating-pin assembly allows tighter pin to pin-bore tolerances and reduces noise generated during engine operation.
RETURNLESS FUEL INJECTION FOR MARINE APPLICATIONS
All Vortec 8100s built for marine application are equipped with a new ``returnless’’ fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system, and was introduced on Vortec 8100s built for the Chevrolet Silverado and GMC Sierra for model year 2004.
Before model year 2004, the sequential fuel injection (SFI) on all Vortec 8100s used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the tank. The new system eliminates the return lines and moves the fuel pressure regulator from the fuel rail on the engine to the fuel tank. The fuel line from the tank now includes pulse dampeners, or a series of baffles, that manage fuel pulsing and limit noise.
Because it delivers only the amount of fuel need by the injectors, and returns no fuel to the gas tank, the returnless system essentially eliminates heat transfer from the engine to tank. This reduces the amount of vapor generated in the tank and released as evaporation. The returnless system has been introduced on marine engines to give marine customers the same emissions standards and efficient operation as truck customers.
IMPROVED OIL PAN FOR MEDIUM DUTY AND MARINE APPLICATIONS
The oil pan on Vortec 8100s built for medium-duty (C4-C8 trucks) and marine use has been redesigned. This cast aluminum oil pan is essentially identical for both applications, with differences limited to final machining.
With the new pan, the interior baffle has been reconfigured to maximize oil flow, improve durability and stiffen the cast-aluminum pan’s structure, further reducing engine vibration. Moreover, sump capacity for medium-duty trucks increases 3.1 liters. The change was driven by the demands of the commercial fleet and rental markets. Rental truck customers may not be the most diligent operators when it comes to monitoring oil levels. The larger sump adds an extra measure of security for rental companies and fleet operators, even if customers use trucks for weeks without checking oil levels.
IMPROVED THROTTLE ACTUATOR CONTROL MODULE
All Vortec 8100’s are equipped with an improved throttle actuator control (TAC) module. Located on the throttle body, the TAC module is an integral component of the Vortec 8100’s electronic throttle control (ETC) system. The TAC takes command from the powertrain control module (PCM) and then operates the motor that opens and closes the throttle plate.
The TAC module has new read-only memory and control software. Like its predecessor, it allows multiple throttle progressions or algorithms, which operate the throttle at varying rates according to operating conditions and driver demands. It also has built-in default settings that protect the engine and ensure safe operation in the event of malfunction with the ETC or other engine subsystems.
RATE-BASED DIAGNOSTICS
The Vortec 8100’s powertrain control module (PCM) uses a new monitoring protocol known as rate-based diagnostics. Rate-based diagnostics improve the robustness of the Onboard Diagnostics System (OBD II) and ensure optimal performance of emissions control systems.
With rate-based diagnostics, the PCM applies a new formula to manage OBD II. Essentially, new software increases the frequency at which the PCM checks various engine systems, and particularly emissions-control systems such as the catalytic converter, oxygen sensors and exhaust gas recirculation (EGR). Rate-based diagnostics more reliably monitor real-word operation of these systems, and allow regulatory agencies to more easily measure and certify emissions compliance. The new protocol allows the Vortec 8100 to meet more stringent OBD II requirements two years ahead of a mandate by the California Air Resources Board.
GF-4 ENGINE OIL
All Vortec 8100s will be shipped to customers with a new engine oil that reduces engine deposits, extends oil change intervals, improves fuel economy and extends the life of emissions control systems. GM Powertrain has taken a leading role in developing and introducing the new oil, designated GF-4 (for “Gasoline Fueled, Standard 4’’) by the American Petroleum Institute.
GF-4 contains a new ash-free antioxidant ingredient and less phosphorous than the previous formulation (GF-3). The typical automotive engine now operates at a much higher temperature than an engine built 10 years ago. GF-4 is twice as resistant to oxidizing, which can present itself as foaming, at high operating temperatures. At the same time, GF-4 provides better low-temperature protection, reducing engine wear during the critical cold-start period. Lower phosphorus and sulfur content – chemicals that are harmful to catalytic converters – will extend anticipated catalyst life beyond 120,000 miles. Finally, GF-4 lowers friction overall and retains its optimal friction-reducing characteristics longer. The result is an anticipated improvement of 0.2 percent to 0.3 percent in an engine’s fuel economy, and longer oil change intervals.
Production of Vortec 8100s with GF-4 begin in fall 2004, ahead of an industry recommendation of April 30, 2005. This will allow vehicles with the Vortec 8100 to be tested for 2005 Corporate Average Fuel Economy (CAFE) standards with GF-4. GM’s industry-leading Oil Life System may be adjusted to account for the new oil. The owner’s manual in vehicles equipped with the Vortec 8100 will continue to recommend oil with the Starburst logo, which must be certified to GF-4 by May 2005.
OVERVIEW
Few words generate excitement for car and truck enthusiasts like ‘’Big Block.’’ The Vortec 8100 V-8 is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the large displacement gasoline engines offered in competitors’ heavy-duty pickups. This heavy-duty engine also sets benchmarks for marine and industrial application worldwide.
Introduced in the 2001 Chevrolet Silverado and Suburban and GMC Sierra and Yukon XL, the Vortec 8100 was essentially a new engine. Nearly 90 percent of its parts have been completely redesigned. While it shares its valve centers, bore centers and bore diameter with the previous 7.4L Big Block, stroke was increased 9.4 mm (.37 inch) to increase displacement 700 cc. The latest math-based engineering tools were used to improve the flow and distribution of oil and coolant, to refine castings and to improve production quality and efficiency.
After extensive analysis of competitors' engines, the Vortec 8100 development team set a goal of 200,000 miles of useful life without major repairs – and then achieved it. Before it was ready for production, this big block had to pass the “Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours without a failure, and a minimum of 1,000 hours at full-throttle operation for truck applications.
In the four years since its launch, virtually every aspect of the engine – from sealing to electronic management to noise, vibration and harshness control – has been re-examined and improved. For 2004, Vortec 8100s built for truck installation were equipped with a new returnless fuel injection system that eliminated fuel return lines between the engine and the gasoline tank and reduced evaporative emissions. Combined with new intake manifold and throttle body gaskets, manufactured of an advanced fluorocarbon material that is virtually impermeable to hydrocarbon molecules, the returnless fuel system allows the Vortec 8100 to meet near-zero evaporative emissions standards. Also in 2004, Vortec 8100s built for industrial applications were equipped with new valves, valve seat material and springs designed expressly for industrial operation at low, steady rpm.
GM's leadership in big-block V-8 technology dates to at least 1958, when the Vortec 8100's progenitor was launched with 348 cubic inches of displacement in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400 – a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8100 bears little resemblance to those engines, but it maintains a tradition of outstanding durability and class-leading power.
VORTEC 8100 8.1L V-8 (L18)
2006 model year summary
• Increase to 325 horsepower for Chevrolet Suburban, Avalanche and GMC Yukon XL
• New dual mid-coupled converter system
• Returnless fuel injection for Chevrolet Kodiak and GMC TopKick
• Improved electronic throttle control pedal and throttle actuator control (TAC) module
• Recalibrated P59 engine controller
Full descriptions of new or changes features
Increase to 325 horsepower
For the 2006 Chevrolet Suburban, Avalanche and GMC Yukon XL 2500 Series, the Vortec 8100 delivers an additional 5 horsepower. Increased power results from reduced backpressure in the exhaust system, enabled by a new catalytic converter system. The new converter system is primarily designed to lower emissions. The Vortec 8100’s new rating is 325 horsepower and 447 lb.-ft. of torque.
New dual mid-coupled catalytic converter system
Chevrolet Suburban, Avalanche and GMC Yukon XL three-quarter-ton models equipped with the Vortec 8100 receive a new M120 mid-coupled catalytic converter system. Two new mid-coupled converters replace four previous ones (two mid-coupled and two under-floor converters). The new dual converters, with about two liters of volume, are also located closer to the exhaust manifold to enhance their effectiveness. Their construction, consisting of multiple materials, is unchanged. While providing lower LEV emissions levels, the new converter system also allows a more moderate 47.1 kPa of exhaust back pressure for more power. Induction restriction is unchanged.
Improved electronic throttle control and throttle actuator control module
With the Vortec 8100, the Chevrolet Suburban, Avalanche and GMC Yukon XL 2500 Series also receive an improved electronic throttle control pedal and improved throttle actuator control (TAC) module. The throttle pedal provides more consistent truck-to-truck pedal force and effort feel for vehicle operators. The TAC is designed to accommodate the new pedal.
Located on the engine side of the front of dash, the TAC module is an integral component of the Vortec 8100’s electronic throttle control (ETC) system. The TAC takes command from the powertrain control module (PCM) and then operates the motor that opens and closes the throttle plate.
Like its predecessor, the TAC module has read-only memory and control software. It allows multiple throttle progressions or algorithms, which operate the throttle at varying rates according to operating conditions and driver demands. It also has built-in default settings that protect the engine and ensure safe operation in the event of malfunction with the ETC or other engine subsystems.
Returnless fuel injection for Chevrolet Kodiak and GMC TopKick
For 2006, the Vortec 8100 available in Chevrolet Kodiak and GMC Topkick medium duty trucks is equipped with a new "returnless" fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system. The system is already used with the Vortec 8100 on Chevrolet Silverado and GMC Sierra models and with all Vortec 8100s built for marine applications.
Before 2006, the Sequential Fuel Injection (SFI) in medium duty trucks equipped with the Vortec 8100 used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the fuel tank. The new system eliminates the return lines and moves the fuel-pressure regulator from the fuel rail on the engine to the fuel tank. But because the returnless system delivers only the amount of fuel needed by the injectors, and returns no fuel to the fuel tank, it eliminates heat transfer from the engine to the fuel tank. This reduces the amount of vapor generated in the tank and captured by the evaporative emissions control system.
Recalibrated P59 engine controller
The Vortec 8100’s P59 engine controller in medium duty trucks is recalibrated to coordinate with the newly available version of the Allison five-speed automatic transmission and the returnless fuel injection system. The P59 also has new calibrations to optimize driveability and fuel economy with the new Allison six-speed automatic transmission being introduced for the first time in GM full-size pickups.
Overview
Few words generate excitement for car and truck enthusiasts like ‘’Big Block.’’ The Vortec 8100 V-8 is the legendary GM Big Block for a new millennium, with a longer expected useful life and horsepower and torque that surpass the large-displacement gasoline engines offered in competitors’ heavy-duty pickups. This heavy-duty engine also sets benchmarks for marine and industrial application worldwide.
Introduced in the 2001 Chevrolet Silverado and Suburban and GMC Sierra and Yukon XL, the Vortec 8100 was essentially a new engine. Nearly 90 percent of its parts have been completely redesigned. While it shares its valve centers, bore centers and bore diameter with the previous 7.4L big block, stroke was increased 9.4 mm (.37 inch) to increase displacement 700 cc. The latest math-based engineering tools were used to improve the flow and distribution of oil and coolant, to refine castings and to improve production quality and efficiency.
After extensive analysis of competitors' engines, the Vortec 8100 development team set a goal of 200,000 miles of useful life without major repairs – and achieved it. Before it was ready for production, this big block had to pass the “Marine Dock'' test, in which it is run at full throttle for 300 consecutive hours without a failure, and a minimum of 1,000 hours at full-throttle operation for truck applications.
In the five years since its launch, virtually every aspect of the engine – from sealing to electronic management to noise, vibration and harshness control – has been re-examined and improved.
For 2005, the Vortec 8100 was made available in Chevrolet Kodiak and GMC TopKick trucks with four-wheel drive. GM’s big block was fitted with floating-pin piston rings, which allow tighter pin to pin-bore tolerances for quieter operation and increased durability. Returnless fuel injection was incorporated in all marine applications. Medium duty trucks received an improved oil pan. All Vortec 8100s received an improved throttle actuator control. Their powertrain control module began using a monitoring protocol, known as rate-based diagnostics, to increase the robustness of the Onboard Diagnostics System and optimize performance of the emissions control systems. All Vortec 8100s
began being shipped with GF-4 engine oil that reduces engine deposits, extends oil change intervals, improves fuel economy and extends the life of emissions control systems.
For 2004, Vortec 8100s built for Chevrolet Silverado and GMC Sierra pickups were equipped with a new returnless fuel injection system that eliminates fuel return lines between the engine and the gasoline tank and reduces evaporative emissions. Combined with new intake manifold and throttle body gaskets, manufactured of an advanced fluorocarbon material that is virtually impermeable to hydrocarbon molecules, the returnless fuel system allows the Vortec 8100 to meet near-zero evaporative emissions standards. Also in 2004, Vortec 8100s built for industrial applications were equipped with new valves, valve seat material and springs designed expressly for industrial operation at low, steady rpm.
GM's leadership in big block V-8 technology dates to at least 1958, when the Vortec 8100's progenitor was launched with 348 cubic inches of displacement in the full-size 1958 Chevrolets. The 348 was followed by several variants, including a 409, 366 and 427. In 1970, the 454-cubic-inch big-block was introduced. It was retooled in 1991 as the Vortec 7400 – a truly powerful pickup engine that met stringent 1990s emission requirements. The Vortec 8100 bears little resemblance to those engines, but it maintains a tradition of outstanding durability and class-leading power.