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Gen III and IV GM Small Block V-8 Engines - Lego EnginesGet Massive Power From Gen III And IV GM V-8s From the August, 2008 issue of 4Wheel & Off-Road By Fred Williams Photography by Fred Williams
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There Was A Muscle Awakening under the hoods of General Motors' vehicles beginning with the '97 Corvettes, '98 Camaros, and '99-'03 pickup trucks. It was the start of the Generation III and IV V-8 engines (also known as the LS series), and the resulting powerplants have breathed horsepower numbers into the tried-and-true Chevy small-block that are so easily attainable it's silly. This new generation of fuel-injected V-8s is simple to build, easy to modify and swap into older 4x4s, and can be pushed to over 400 hp with simple computer upgrades. In fact, 500hp Gen IV engines are commonplace and 700-plus-horsepower crate engines based on this architecture aren't unheard of. We spent a day at Turnkey Engine Supply assembling a Gen IV 6.0L LS2 and can honestly say we've seen Legos more complicated. In fact we're not sure why you wouldn't choose a Gen III or IV engine. Whether you are dragging one home from a junkyard or considering an all-new crate engine, when you learn how simple and powerful these engines can be and how plentiful they are, it's a no-brainer. Late-model Chevy small-block V-8s are as good as they've ever been, if not better.  1. We were at Turnkey Engine...  1. We were at Turnkey Engine Supply to see the assembly of an LS2, which is an all-aluminum-block 6.0L (approximately 366 ci). These are available as either brand-new crate engines from Turnkey, or can be sourced from a junkyard Cadillac CTS-V, Chevrolet Corvette, SSR, TrailBlazer SS, and Pontiac GTO. The LS2 is similar in architecture to the complete line of Gen III and IV engines, including the common and inexpensive iron-block truck 4.8L, 5.3L, 5.7L, and 6.0L models.  2. The LS2 block is a four-bolt...  2. The LS2 block is a four-bolt main style which means there are four bolts holding the main bearing caps of the crank. However, these engines are sometimes referred to as six-bolt mains due to the additional two side bolts which come in from the outside of the block for added block stiffness and low-end strength. Though the block is aluminum, the main caps are steel, which helps in the longevity of the engine.  3. The Gen III and IV engines...  3. The Gen III and IV engines do not use a distributor, but instead use a coil pack at each spark plug. This means the computer determines ignition timing as well as injection timing for each fuel injector. To monitor the stroke of the engine, a camshaft sensor picks up a signal off the camshaft in front of the LS2, while on the LS1 it is on the rear of the camshaft. There is also a crank position sensor that picks up a signal from a crank-mounted tone ring (be cautious of the LS2 from the '05 GTO as they have a different crank sensor from later LS2s).  4. The rods in these late-model...  4. The rods in these late-model engines are made of powdered metal and use a cracked metal design for alignment with the bearing caps. Made in a manner similar to both casting and forging, the metal powder is put in a mold, compressed, and then heat-treated. This process results in a strong lightweight part that uses less waste and ends up with a very uniform grain structure. Plus when the cracked cap design is used, the grain of the metal acts as an alignment grid to help fix and strengthen the rods. Turnkey uses these stock parts for most of its crate engines, but it does upgrade to forged pistons and ARP rod bolts to overcome some of the weaknesses of the original cast pistons.  5. The Gen III and IV oil...  5. The Gen III and IV oil pan is cast-aluminum with a reusable gasket, has dual windage trays to help against sloshing, and keeps oil near the pick up. A few different oil pans are available, but it is generally believed that the Camaro pan is better for off-roading. The truck pan is best for holding oil, but can also be too deep depending on suspension and hoodline layout. Most factory transmissions use a thick-cast lower torque-converter cover that ties into this oil pan for added strength, but we haven't found any aftermarket torque-converter covers that can be added to the older transmissions like the TH400 and TH350. If you know of any, please let us know as this could be a great upgrade component.  6. One notoriously bad feature...  6. One notoriously bad feature of the LS engines is the lack of oiling when pointed nose-up on extreme angles. The guys from Twisted Customs have found an aftermarket steel oil pan that is similar in style to the Camaro pan, so that it doesn't hang down especially low, but it also has internal baffles and trap doors to keep feeding oil during steep climbs.
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