Ever since the release of the original small-block Chevy in 1955, Chevrolet engines have been the king of all engine swaps. Some of this is due to the sheer production volume of these engines, but in modern times, aftermarket support and ease of installation has allowed Chevrolet to continue dominating the realm of engine swaps. While the LS platform remains the current king of swaps, the LT series of direct-injected V-8s and lone V-6s are primed to take over.
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In 2013, General Motors released the Gen V platform, which will eventually replace the LS-series engine in all platforms. The Gen V shares the look of the III/IV series, but in reality, it is all new. The biggest advancement in the LT-series is the use of direct injection, where the fuel is sprayed directly into the combustion chamber at high pressure (2,175 psi for the LT1), which aids in fuel economy and overall performance through better fuel atomization. Direct injection also makes cylinder deactivation more efficient, further increasing fuel economy. The 2014 LT1 Corvette can get as good as 29 miles per gallon (mpg). Other advancements include piston oiling jets, active fuel management, and continuously variable valve timing.
Because of the direct-injection method, the intake valves must be cleaned regularly—some suggest every 5,000 to 10,000 miles. This is performed with a spray-in additive while the engine is running. If this is not done, the intake valves get gunked up, causing serious drivability issues. This is the nature of direct injection.
The LT5 engine has a second set of injectors in the intake above the intake valves. This eliminates the need for the cleaning agent, but all other LT-series engines need this process. A rule of thumb is to clean them at every oil change to make sure that you don’t forget. It is a required service at least every 25,000 miles, which is three oil changes because Gen V engines have a recommended oil-change interval of 7,500 miles. This is preventative maintenance to eliminate the larger expense of a top-end rebuild.
LT Car Engines
Chevrolet Performance currently has three crate versions of the Gen V: a naturally aspirated 6.2L 460-hp LT1 (the engine installed in the base-model C7 Corvette), the supercharged 6.2L 650-hp LT4 (the engine in the Z06 version of the C7 Corvette), and the LT376, the newest LT-series crate engine that is essentially a hopped-up naturally aspirated LT1 with GM’s high-lift LT1 Hot Cam and CNC-ported heads, generating 535 hp on a base tune. The LT1 for Camaros is rated at 455 hp.
Most swappers procure factory-installed engines. These powerplants have been installed in GM trucks and SUVs beginning in 2014 (1500 series only) as well as Corvettes and Camaros. The 4.3L LV3 Ecotec V-6 is the 6-cylinder variant of the LT-series, which is available in 1500-series GM trucks as well.
6.2L LT1
Making 460 hp without a supercharger is not easy, and to do so while hitting 29 mpg is even harder, but the LT1 does exactly that. The 4.06-inch bore combined with the 3.62-inch stroke creates an 11.5:1 compression ratio, which makes efficient use of the fuel pumped through the direct-injection nozzles. A forged crank, hypereutectic pistons, and forged powdered metal rods yield light weight and durability. The heads are conventional aluminum castings and feature lightweight sodium-filled valves. There two oiling systems available: a wet sump and a dry sump.
6.2L LT4
To pump up the output of the LT1, General Motors dropped a supercharger onto the 6.2L block to make 650 hp. To make that work long-term, some changes were made to the rotating assembly. The crank is the same, but the rods were slightly redesigned to increase strength in key areas. The pistons in the LT4 are forged, and the combustion chamber was opened up, decreasing the compression ratio to a boost-friendly 10.0:1. The heads are rotocast, making them stronger and better at handling higher heat ranges. The valves are solid titanium, and the oiling system is a dry-sump design, same as the LT5, and is an option on the LT1.
6.2L LT5
In late 2017, General Motors announced the release of the newest version of the Gen V LT-series engine: the LT5. This is a supercharged V-8 that is similar to the LT4, except this monster motor uses a higher-output supercharger and a redesigned crankshaft and new fuel injection system to generate 750 hp and 715 ft-lbs of torque. The most powerful GM production engine is slated for installation in the 2019 Corvette ZR1. The oiling system is dry sump only.
Gen V Truck Engines
Beginning in 2014, all GMC/ Chevrolet trucks, vans, and full-size SUVs with V-8 gasoline engines came with Gen V engines. There are currently three truck versions: the LV3 4.3L (LT-based V-6), the L83 5.3L V-8, and the L86 6.2L V-8. The V-6 is an LT-series engine, essentially a V-8 with two cylinders cut off. The V-8s are the most common for trucks and SUVs.
4.3L LV3
A V-6 in a swap book? Some might balk at the idea of swapping a V-6 when they could swap in a V-8, but consider the merits of the 6-banger before writing it off. For starters, it is an LT engine with two cylinders lopped off, just like the previous 4.3L V-6, which was based on the second-gen model (also named LT1, coincidentally). The LV3 features 11.0:1 compression with 99.6-mm bore on a 92-mm stroke, maxing the RPM at 5,800. It uses a forged steel crank with powdered metal connecting rods and caps, just like the rest of the Gen V LT family.
With 285 hp and 305 ft-lbs of torque, this diminutive powerplant has the potential to make 400 hp with minor upgrades. It could easily reach 350 hp with just a simple tune. The V-6 platform has a smaller block, which provides more options for swap projects. Fitting this 6-cylinder into say an MGB is much easier than the V-8 version, and it can make almost as much power. The fuel economy on the LV3 is 18 city, 24 highway in trucks that weigh upward of 6,000 pounds. Drop that into a 2,500-pound Euro sports car, and the economy will be substantially better.
5.3L L83
This engine features a 3.78- inch bore, 3.62-inch stroke, and 11.0:1 compression ratio. These engines make 355 hp and 383 ft-lbs of torque with gas, while E85 produces 376 hp and 416 ft-lbs. Readily available from most salvage yards, these engines are not yet in demand because they are so new. Prices are currently under $2,000 for a complete L83, and the ECM and fuel-pump modules are inexpensive too. Once these models begin wearing out engines and the swap market picks up, the prices will go up. An LT-based engine will be cheaper than an LS Vortec, and the LTs have fewer miles.
In 2014, the LT1 stormed onto the scene in the Corvette. This 460-hp beast features direct injection, where the fuel is sprayed directly into the combustion chamber, ensuring adequate combustion. The science behind how this works is fascinating. There was a lot of interest in swapping these engines, but the fueling system kept the swaps from taking hold at first. (Photo Courtesy General Motors)
General Motors quickly released the LT4, a supercharged version of the LT1. Basic changes were lower-compression heads (down from 11.5 to 10:1) and a big supercharger. The LT4 is good for 650 hp in stock tune. (Photo Courtesy General Motors)
Because everyone needs more horsepower, General Motors created the LT5. This beast adds 100 more ponies over the LT4, for a total 750 hp and 715 ft-lbs of torque. The last C7 Corvette, the ZR1, received this engine in 2019, and it is now available as a stand-alone crate engine. (Photo Courtesy General Motors)
While most would dismiss a V-6, the LT series has a V-6 in the lineup, and it is pretty impressive in its own right. It is 285 hp stock; a tune would easily take it to 350; add a turbo, and it could probably get into the 500s. Plus, it is small and lightweight, so it can fit in cars where a V-8 won’t. This engine is found in GM trucks and vans. (Photo Courtesy General Motors)
General Motors rolled out the LT series right away in all trucks and SUVs with the L83 5.3L V-8. Having 355 hp and extremely good fuel economy make this a great engine for a swap. There are tons of them out there in low-mileage wrecked trucks. (Photo Courtesy General Motors)
You can’t leave all the fun to the cars, so General Motors dropped the L86 6.2L V-8 into the high-end Denali and High Country truck models, and in 2018, the company began offering them in the high-end SUVs as well. At 420 hp with pull well into triple digits, these 6.2L L86s can do impressive things in a 6,500-pound truck. Capable of low-14-second quarter-mile times and a blistering 5.4-second 0–60 time, the L86 6.2L engines are more than capable. They are harder to find, and cost more, but they are worth every penny. (Photo Courtesy General Motors)
6.2L L86
The L86 is a modified LT1 that makes 420 hp and 460 ft-lbs of torque. The LT1 and L86 are very similar down to the compression ratio of 11.5:1. If you want any of the larger 6.2L Gen V engines, you are going to pay for it, but not as much as a 6L LS will cost. Current prices are in the $2,500 to $5,000 range for an L86 from a low-mileage wreck.
Fuel economy from the L86 is quite impressive as well. GM trucks with this engine often see 22–25 mpg on the highway, which is incredible for trucks weighing in at 6,000-plus pounds. In my personal 2015 GMC Denali 1500, a 25-mile best of 34.7 mpg was recorded. This was under perfect conditions and in a slight downhill stretch, but it happened, and it was spectacular. The physical differences between the LT1 and the L86 are: the intake (the L86 intake is larger and makes more torque), the exhaust system, and there is the optional dry-sump oiling system for LT1s. The extra 40 hp comes from tuning and the intake. They even share the same camshaft.
Engine-Swap Projects
The goal of this book is to assist in an LT-series engine swap. Whether swapping a 1969 Chevy truck, a 1970 Chevelle, or a 1999 Miata, the information in this book will help you achieve your goals. Performance is typically the number one goal of any engine swap, and the LT-series offers that in spades. As these engines become more popular, the aftermarket is rapidly producing more performance components. Spicing up an LT engine is almost as easy as ordering the parts themselves.
The main concerns for LT swaps are fitting the oil pan, accessory drive, power steering, and fuel system. Another issue is the exhaust (mainly headers or manifolds) because the head design for LT engines is different from the LS series, and there are simply not very many options for swaps, so you need to get a little creative. Luckily, there are more options now than there were six months ago, so by the time you read this book, there will be even more options available for your LT swap.
This Tech Tip is From the Full Book, HOW TO SWAP GM LT-SERIES ENGINES INTO ALMOST ANYTHING. For a comprehensive guide on this entire subject you can visit this link:
LEARN MORE ABOUT THIS BOOK HERE
SHARE THIS ARTICLE: Please feel free to share this post on Facebook Groups or Forums/Blogs you read. You can use the social sharing buttons to the left, or copy and paste the website link: https:// lsenginediy.com/what-is-an-lt-engine-the-complete-guide-to-understanding-gms-marvel/
Locating an LT engine is as simple as ordering a crate engine from a dealer, parts house, or local salvage yard. There are distinct differences between the car and truck engines. All truck engines have a longer crank pulley, which is because the truck engines use an engine-mounted belt-driven vacuum pump for the brake assist. Additionally, the truck engines use a driver-side biased water pump (all LT pumps are offset), while the car engines use a passenger-side offset pulley. This is not a big deal for most applications, but the accessory drives can’t be interchanged without swapping all of it.
Swapping Problems
The LT-platform has tons of potential for increased performance, but there are some caveats that must be addressed for swaps. The main issues are the fuel system and the lack of a power steering pump. Both of these are addressed at length in the pages of this book, but it is something that you need to know going into planning an LT swap.
Nearly every new vehicle uses electric power steering. This reduces drag on the engine and gives the manufacturer the ability to tune the steering assist based on vehicle speed. There are options for aftermarket electric power steering, such as with American Powertrain, otherwise an aftermarket accessory drive can be used on an LT engine to have traditional power steering. This is the main reason that General Motors is not using the LT engine in the larger 2500- and 3500-series trucks. These vehicles use a hydroboost for the braking system, and they simply need to have a power steering pump to provide the hydraulic pressure for the hydroboost.
The fuel system is the other major departure from the traditional swap. LT engines are direct-injected, which uses a PWM fuel pump without a return line to feed the engine with up to 76 psi of fuel pressure. From there, the engine further increases the fuel pressure with a mechanical fuel pump. The chassis or tank pump is therefore a lift pump, essentially moving the fuel from the tank to the engine. The complexities of the fuel system are addressed in chapter 8.
Outside of these two areas, an LT swap is fairly simple. There are some notable differences from other engine platforms, but that is to be expected. The rest of this book deals with how to perform a swap and covers most of the details. While every car and swap are different, there are quite a few common aspects.
Swapping an LT engine into just about anything is not the most complicated automotive endeavor. An average swapping project is fairly easy if it is carefully conceived, researched, and planned. The Gen V LT engine shares a similar footprint with the original small-block Chevy. The general rule of thumb is that if a small-block fits, an LT will fit as well, with some minor adjustments of course. Engine position, oil pan, and accessory drives are the most common physical fitment issues.
Unlike previous fuel-injected engines, there is no carbureted option for LT-series engines. The nature of direct injection prevents the possibility of using a carburetor. This means that every LT swap requires using an electronic control module (ECM) and sensors. In most cases, you must carefully modify the wiring harness, plugs, and wiring, or purchase the correct aftermarket components for plugging in the particular engine to a specific car. Chevrolet Performance, Howell EFI, HP Tuners, and many others offer products and tuning that make swapping the electronics much easier. In the end, you get a more efficient powerplant with the ability to tune it better and faster.
one of the most affordable ways of procuring a GM LT-series engine is through a salvage yard. Because these engines are so new, the demand is quite low, but people wreck trucks every single day. When a new truck is totaled, it goes to a salvage yard. While body panels and interior pieces are in demand for repairs, the drivetrains are so new that there just are not very many on the road with enough miles on them to break down. In fact, many of these vehicles are still under warranty. This means the market is in the prime position to buy low-mileage LT-series engines at a substantial savings. Within the next five years, the price of these engines will go up considerably.
If you have never purchased a salvage engine, you may be a little leery of the process. While you can certainly be taken advantage of, the more you research, the better off you will be. There are several keys to successfully buying a salvage engine: knowing where to buy, knowing what you are buying, and finding what parts are available.
Where to Buy
Knowing who you are buying from is just as important as knowing what you want. The internet is a glorious tool for helping weed out the undesirable salvage yards that take advantage of their customers. Salvage yards often have a reputation for being sleazy, and those certainly still exist, but the more-reputable yards get better reviews online, helping you make a more informed decision on where to buy. There are some salvage yard networks, such as LKQ, that link qual- ity yards together so that you can find the parts you need from all over the country.
Then there is the pull-a-part-style yard, where you remove the parts that you need. These yards are usually less expensive.
However, you need to research the parts, find the vehicle, and remove the parts using your own tools. Some yards pro- vide cherry pickers or forklifts to remove large parts, such as engines, while others do not. That is the caveat emptor of salvage yards: research the yard and ask questions.
Know What You Are Purchasing
Purchasing a used engine means dealing with a shop or salvage yard that has dismantled a vehicle. When it comes to engines, most yards want to get the job done as quickly as possible and break the vehicle down to as many sellable parts as possible. This means that for most engines, the wiring harness gets chopped along with the fluid lines. Most yards remove the peripheral components, including the throttle body, alternator, starter, and air-conditioner compressor. Some yards strip engines to the long-block, meaning no intake, exhaust manifolds, or water pump as well. It pays to ask what comes with the engine when you are researching your purchase. You might pay an extra hundred or two for a complete engine, but buying the peripheral components can cost thousands in the end.
If at all possible, get the ECM and throttle pedal from the same vehicle. It is not absolutely critical, but it is nice to know everything is already paired together.
Get the Vehicle Information
Because there are some key differences in the engines themselves, you need to know where your engine came from. While the original vehicle’s vehicle identification number (VIN) is not as important, get the year, make, and model of the vehicle, along with the original mileage. There are small differences between year, make, and model for each engine, and you need that information readily available for future service.
Parts That Are Available Buying a used engine, whether it is from a salvage yard or a private seller, typically means you are getting part of the package but not the complete package. With LT engines, you need the engine, throttle body, throttle pedal, ECM, wire harness, fuel control module, and accessories. If you can source this all from the same vehicle, that is perfect, but if not, you need to match the components from a similar vehicle and engine.
A V-6 throttle body is different from the 5.3L L83, and the 6.2L L86/LT1/4/5 engines use a different throttle body than the smaller Gen V engines. You can convert to the larger throttle body, but swapping a 5.3L throttle body to a 6.2L will decrease performance. The ECM, fuel modules, and wiring harnesses are the same for the truck engines.
As with any purchase, the more you can research on the seller and the parts you are buying, the better off you will be. Keep in mind that any used engine is just that—used. There are no warranties from General Motors, but many salvage yards offer short-term warranties and even extended warranties that can be a great benefit, which is just one more aspect to consider when shopping for a used LT engine.
When ordering a crate engine, this is what you get: a big box on a pallet. You will need a forklift or pallet jack. This LT1 crate engine was ordered with the complete ECM control package and was installed in the 1971 Buick GS seen in this book.
Inside the crate is a brand-new $8,500 to $10,000 engine, all shiny and clean. Don’t want to spend that much? There are other options. Want to spend more? The LT5 is now available as a crate engine, and you can also order a complete drivetrain with the ECM, transmission, and all the controllers, harnesses, and other components needed for the drivetrain itself. This does not include the fuel system, mounts, or accessories.
This is what $1,500 will get from just about any larger salvage yard: an engine without any accessories or wires. We scored this one from LKQ, a national chain of salvage yards, for $1,575 with free shipping because it was local. You don’t get the throttle body, and usually you don’t get the exhaust manifolds either. We were lucky. This take-out engine found its new home in a 1987 Camaro built for this book.
Salvage yards leave the harness plugs attached. Most of the time you can’t get a salvage harness, because it takes too long to strip it out, so they just chop the wires. We have tried requesting a used harness, but they always tell us they won’t do it. This varies yard to yard. All the sensors are there.
Written by Jefferson Bryant and republished with permission of CarTech Inc
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