Stock accessory drives were designed to fit in late-model vehicles with modern frames and spacing. Depending on which accessory drives are retained, clearance may or may not be an issue. However, the A/C compressor constantly presents an issue. It’s typically mounted low on the passenger’s side of the engine, and it tends to hit the frame rail or the upper A-arm on the suspension at this location.
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On the other side of the engine, power steering pump and alternator placement becomes an issue. The stock recirculating-ball steering gearbox gets in the way. Each chassis is different and each accessory drive is different.
Stock Accessory Drives
Specific stock accessory drives work on specific chassis. If the drive system doesn’t fit your car, there are several options. The first is to find a stock drive that fits your chassis, but these can be difficult to find, especially the older 1998–2002 F-Body drives. There are also quite a few aftermarket drive kits that not only relocate the offending components, but also add some flash to the install. The last solution, relocating the problem component with a home-fabricated bracket, requires a little more ingenuity and fabrication. When swapping an LS into a less traditional vehicle, the possibilities are endless. In many cases, the chassis and suspension is modified to accept the LS engine. In addition, each vehicle’s purpose helps determine the accessory drive choice. Vehicles that do not run A/C or power steering are certainly easier to fit and modify than a project that requires all of the accessories: keep that in mind when choosing your accessory drive. An alternator alone is much easier to relocate than three components.
Engine-to-radiator clearance is a primary consideration when installing an LS engine into a non-GM vehicle. The LS engine may be physically larger than the engine it is replacing, or you may move the engine farther forward. In each of these cases, clearance may be reduced, so selecting compatible accessory pulleys is imperative. With many swap projects in which clearance is minimal, an electric fan must be used. (Photo Courtesy Blane Burnett)
The accessory drives on Gen III/IV engines are interchangeable throughout the product line. However, each accessory drive is based on two components: the water pump and the harmonic dampener (or harmonic balancer; LS engines are internally balanced, so it is technically a harmonic dampener, but commonly referred to as a balancer).
Water Pumps
You have three water pump offset options: the 1998–2002 F-Body, the Corvette, and the C/K trucks. Within these types are subgroups. The F-Body water pump remained the same throughout its production run, from 1998 to 2002.
The Corvette (also GTO in 2004) used one water pump design with some internal differences. The 2005-up Corvette/GTO water pump for the LS2, LS7, and LS3 used the same offset, but contained a different internal design.
The main difference between these two water pumps is the length of the pulley bell. The Corvette-style pump (top) has a longer bell because the Corvette accessories run on two belts. The F-Body pump (bottom) uses a single belt. (Photo Courtesy Street & Performance)
The same is true for the C/K truck pumps. The 1999–2005 trucks use a specific water pump, but in 2007 the design changed to DoD. Not all 2007 C/K engines use this pump. The offset remains the same as with early pumps, but you do not want to swap a DoD pump onto a non-DoD engine. The LS1/LS3 pumps are interchangeable; the LS3 pump uses a lighter pulley, with about 4 pounds of weight savings.
Harmonic Dampeners
The crank pulley is part of the dampener; it is one piece as opposed to a separate pulley that bolts to the balancer. There are three balancer designs for the LS engines.
The Corvette (Y-Body) dampener is the shortest of the three, placing the drive belt close to the engine.
The F-Body (also GTO) dampener is 3/4 inch longer than the Corvette engine.
The C/K (GM truck engine’s 4.8-. 5.3-, and 6.0-liter) unit is 11/2 inches longer than the Corvette unit.
This correlates to the water pump as well.
GM Vehicles
Each GM vehicle accepts a certain stock drive. Matching the drive to the car saves money in the long run and probably some headaches as well. The following breakdown refers to fully accessorized engines running A/C and power steering. If you are not running A/C or power steering, other drives may work; it depends on the vehicle and the drive system.
This is the 1998–2002 LS1 F-Body drive system. The accessories fit somewhat tight to the engine, but the A/C compressor and alternator can still be difficult to fit to the chassis. (Photo Courtesy Street & Performance)
The 1997–2004 Corvette has a dual-belt drive. The alternator is raised so it clears narrower frames. (Photo Courtesy Street & Performance)
The 2005–2006 GTO accessory drive system features an A/C compressor that hangs fairly wide, so it’s more difficult to fit between the frame rails. (Photo Courtesy Blane Burnett)
1958–1972 GM Muscle Cars and Early Corvettes
The C5 Corvette (Y-Body) accessory drive fits most GM muscle cars; C2, C3, and C4 Corvettes; and clears the stock chassis and stock chassis components with most motor mount adapters. The C5 uses a variable clutch-speed compressor that rides low on the smaller secondary four-rib belt. Depending on the motor mounts used, there can be clearance issues.
A Sanden 508 A/C compressor on a Street & Performance bracket positions the compressor forward to clear the chassis and puts the A/C compressor on the larger six-rib belt. You can run other accessory drives in these cars, but the engine crossmember must be notched to clear the A/C compressor, and the alternator hits the frame and steering gearbox.
A rack-and-pinion conversion simplifies the installation. This drive places the A/C compressor low and pushed back on the passenger’s side. The power steering pump mounts in front of the driver-side cylinder head, and the alternator rides up and over the power steering pump.
1967–1969 Camaro, Firebird, 1978–1988 G-Body
The classic Camaro and G-Body cars require the 1998–2002 F-Body accessory drive to clear the chassis. This drive system places the A/C compressor very low and tight to the block, with the compressor centerline just below that of the crank. The alternator is tucked to the driver’s side of the crank pulley and the power steering pump is mounted directly above the alternator.
A Corvette/CTS-V crank balancer is on the left; a mid-length F-Body/GTO is on the right. The rest of the accessory system must match the water pump and balancer.
Tri-Five Chevy, Buick and Oldsmobile
For the classic Tri-Fives, things get a little difficult. The C5 Corvette (1997–2004) accessory drive fits, depending on the chassis and the motor mounts. For a stock chassis using draglink steering, the C5 drive clears if the engine frame mounts set the engine forward.
Street & Performance suggests the Chassis Engineering V-8 engine stand, which sets the engine 3/4 inch forward. If the engine stand positions the engine rearward, you need a custom drive.
C1, C2, C3, C4 Corvette
The C5 Corvette drive system works well in the C2, C3, and C4 chassis without much modification. The C1 Corvette, however, typically requires an aftermarket accessory drive. An LS swap into a C1 also requires converting to a rack-and-pinion steering system, as the factory steering box doesn’t clear the engine itself.
1960–1966 Chevy and GMC Trucks, SUVs
The F-Body and C/K accessory drives work well for this increasingly popular truck line. The C/K accessory drive positions the A/C compressor just below the crank centerline, tucked in really tight to the passenger’s side of the block. The power steering pump mounts tight to the block, midway between the crank and water pump. The alternator is out of the way at the top of the engine, above the power steering pump, next to the throttle body. This keeps everything nice and clean for these trucks.
Vortec engines have the longest pulley setup because trucks have more room to run the belts. Many Vortec engines also use a mechanical cooling fan. (Photo Courtesy Holley Performance Products)
1967–Up Chevy and GMC Trucks, SUVs
In stock form, with all the accessories, the F-Body and C5 drive accessories fit the rest of the GM truck line, but the C/K accessory drive does not fit in completely stock trim. The A/C compressor is the problem and can fail in the C/K drive of these trucks. If you do not use A/C, it fits.
If you do use A/C, the solutions are pretty simple. Either fabricate a custom bracket or purchase an after-market A/C relocation bracket for the C/K drive. Place the compressor on top, where it clears everything. Using a Sanden compressor makes the install nice and clean.
The 1999–up Vortec drive fits all classic truck applications with the exception of the A/C compressor in the 1967–up trucks because the compressor hits the crossmember. You can relocate the A/C compressor or notch the crossmember. (Photo Courtesy Street & Performance)
The CTS-V drive system pulls the A/C compressor in tighter to the block than the GTO, and it uses the shortest crank pulley design for the most room. (Photo Courtesy Blane Burnett)
The Holley LSX accessory drive system comes in all three pulley lengths, and several options are available for positioning the accessories for maximum clearance. It is also available for the factory R4 A/C compressor or Sanden-style units. (Photo Courtesy Holley Performance Products)
Ford Mustangs
Although it might seem like Blue Oval blasphemy, the LS engine is often swapped into the Ford Mustang. The LS is a compact power plant, which makes the swapping process much easier than with many other engines, including the Ford Modular 4.6L and Coyote 5.0 engines. Every model is capable of taking an LS between the fenders; the Fox body is the most popular as well as the simplest.
Sometimes a power steering pump with a built-in reservoir is too large to accommodate a particular swap. A Summit Racing GM Type-II mini-pump is a viable option because it is considerably smaller than the reservoir pumps, although it does require a remote reservoir.
1964–1973
Early Mustangs have very tight engine compartments; the stock shock towers are just in the way. The good news, however, is that the front area of the chassis is relatively clear of obstacles that the accessory drives can hit. The Corvette, CTS-V, and F-Body drives all work well here.
1979–1993 Fox-Body
Swapping an LS into a Ford may seem like sacrilege to some, but it is nonetheless a popular swap. The F-Body drive works well without any modifications, but they are getting hard to find. The ever-present Vortec drive, however, is available on the cheap and it works with a cowl hood. It can work with a stock hood with some modifications.
1994–2004 Mustang (SN95 Body)
For later-model Mustangs, the Corvette and CTS-V drives work well.
Nissan 240SX
The main issue with the 240SX is the limited space between the engine and the radiator and the lower sub-frame rails. The CTS-V drive works well in this regard, pulling the A/C pump tighter to the block and using the short pump design, maximizing the radiator-to-engine clearance.
This Holley power steering pump reservoir is small and compact for discreet installations. LS engines use a GM Type-II pump, some of which have a built-in reservoir, but most do not. (Photo Courtesy Holley Performance Products)
Jeep CJ, YJ, TJ, XJ
All Jeeps can be fitted with F-Body brackets. The Vortec drive can be made to work; however, the alternator is really high and on some bodies it sticks out beyond the hood. There are modifications to reposition the alternator, which means custom fabrication.
This Tech Tip is From the Full Book, LS SWAPS: HOW TO SWAP GM LS ENGINES INTO ALMOST ANYTHING. For a comprehensive guide on this entire subject you can visit this link:
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Mazda
There are two popular LS swap platforms in the Mazda lineup: the RX-7 and the road race legend, the Miata. The lightweight aluminum-block engines work best.
For a little bit of show, this Street & Performance dual-reservoir tank can be used for power steering and any number of other fluids, such as radiator overflow, windshield washers, etc. (Photo Courtesy Street & Performance)
Mazda Miata
As an increasingly popular swap platform, the Mazda Miata has a fair number of LS swap followers. The CTS-V accessory drive has proven to be the best drive for the Miata chassis. The CTS-V drive uses the shorter dampener, so it pulls the belts closer to the block. This saves a lot of room between the radiator and the engine, plus it retains the factory GM power steering pump.
Mazda RX-7
Late-model RX-7s take the CTS-V accessories with only a slight adjustment. The stock power steering pump sits a little high, causing interference with the hood. One solution is an LS2 GTO pump. Another option is to convert to a remote reservoir pump.
The CTS-V pump also requires a pressure reduction kit as the pump creates too much pressure for the Mazda rack, leading to over-assisted steering. As a result the steering is way too fast for safe driving.
Running the stock accessory drive is a cheap solution. That does not mean it is the best solution. Stock drives are not aesthetic. Sure, the brackets are aluminum and can be polished, which looks nice, but that requires a tremendous amount of work and upkeep. Polished aluminum fades and oxidizes pretty quickly, and requires constant attention to retain a mirror finish if it is not anodized to protect it.
In addition, there is no guarantee that the stock drive will fit. The particular install depends on what mounts are used and how the engine is set up; there are always tolerances that may not work in some circumstances. An aftermarket accessory drive simplifies the install, removes the guesswork, and makes sure everything clears.
Cooling System
Swapping LS engines into non-GM vehicles can raise some challenges. For cars that were available with small-block V-8s, the radiator is not that big an issue, but more radical swaps sometimes require custom radiators. In addition, the Gen III/IV car engines were designed for electric cooling fans; only the Vortec engines have mechanical fans.
With a radiator and a fan, there can still be a few more issues. In many cases, the more radical swaps end up with a radiator that sits below the engine, creating air pockets in the cooling system and leading to overheating issues. These issues are easily remedied, but you need the right parts.
Radiators
Gen III/IV engines are typical V-8s with respect to the cooling system, so they do not require huge radiators or special metals. What they do require is a radiator that is rated for the job. With the smallest LS engines easily making 300 hp, you don’t want to use a stock 4-cylinder or V-6 radiator. Making horsepower means making heat as a byproduct, although the LS engines are pretty efficient when it comes to that.
Considering that the most popular GM muscle car and truck swaps had V-8s available from the factory, V-8 radiators are easy to find. And of course with a massive aftermarket catering to these vehicles, there are more than enough choices.
Aluminum radiators come in a million shapes and sizes. Choosing which one is right for your swap can be frustrating. The key is not necessarily to spend the most money. Budget-priced aluminum radiators such as those from Griffin, Summit Racing, and Howe are often just as good as more expensive units. (Photo Courtesy Summit Racing)
This Flex-a-lite aluminum radiator features a built-in overflow canister. Having a custom crossover radiator built with the inlet and outlet on both sides gives you a lot of hose-routing options during an LS swap. However, in some cases the expense is prohibitive. Since most LS engines do not use mechanical fans, routing a hose across the front of the engine is not an issue. (Photo Courtesy Flex-a-lite)
You can also buy a radiator with built-in electric fans. This ensures the fans are properly shrouded, which is an important element for achieving optimal cooling efficiency. (Photo Courtesy Flex-a-lite)
This sacrificial anode from Flex-a-lite gives up its material in the event of electrolysis, saving your valuable components. Electrolysis is known to destroy aluminum heads.(Photo Courtesy Flex-a-lite)
Aluminum versus Brass/Copper: In most 1970s vehicles, OEM radiators are constructed of a mixture of brass and copper. The brass components in radiators (typically the tubes) are expensive and the least effective at cooling an engine. The copper components (the header, and sometimes the tubes), however, quickly absorb and dissipate heat more quickly than aluminum components. Aluminum radiators absorb and dissipate heat better than brass, but at a slower rate than copper.
Copper, therefore, absorbs and dissipates heat at the fastest rate, cooling the engine more effectively than aluminum, right? Not exactly. Aluminum is stronger, which allows for thin-walled cooling tubes, which allows for more cores and rows than a traditional copper/brass radiator for increased cooling surface area. All of this translates into increased cooling capacity. In addition, aluminum is cheaper than brass, which certainly plays a part.
A further issue with brass/copper radiators is that they are soldered together with lead solder. The chemical reaction between the metals leads to contamination and build-up inside the radiator. Solder also insulates the tank from the tubes, reducing the heat transfer between them, further reducing the effectiveness.
In reality, both radiators are useful, but the performance nod is typically given to the aluminum unit.
Electrolysis: Whenever there are two different metals in a coolant system, there is the potential for electrolysis. Electrolysis happens when one material is eaten away and deposited on the other. This can be disastrous for an aluminum engine because aluminum is generally the sacrificed material. When running a copper/brass radiator, there is potential to ruin aluminum components on the engine.
The simple solution is to install an anode kit in the radiator. Anodes are used in machinery and marine applications to protect the cooling systems and other components from damage due to electrolysis (or coolant additive failure and breakdown). Flex-a-lite offers a zinc anode kit (PN 32060) for installation as a replacement drain petcock in radiators that are equipped with a 1/4-inch NPT bushing welded into the tank.
The anode may also be installed in any 1/4-inch NPT hole that is available in the cooling system. The introduction of the zinc anode protects the cooling system from galvanic action as electrolysis eats away at the zinc rather than the aluminum.
Coolant: There has been much discussion about which coolant is best for LS engines, particularly in engine swaps. Dex-Cool is the factory engine coolant and is recommended by General Motors. That being said, those recommendations are for stock vehicles using all-stock components.
Dex-Cool is specifically designed for aluminum radiators, not for copper/brass radiators. Dex-Cool’s harsh and resilient organic acids can attack the solder in copper radiators, eventually causing the radiator to leak.
Dex-Cool also has a tendency to sludge up in the system over time due to contaminants that find their way into the system. When swapping an LS engine, most builders suggest flushing the engine with water three or four times until it comes out clear and there are no more hints of orange.
Once the coolant system is clean, it’s time to add new coolant. Most builders agree that the aftermarket (non-GM) orange long-life equivalent works well in systems with copper/brass radiators. Make sure that the coolant being used says it is compatible with both types of coolant (Prestone, for example).
Of course the good old green antifreeze provides more than adequate performance so long as the system has been properly flushed. Dex-Cool and the standard green antifreeze can be mixed; however, the green antifreeze counteracts the long-life properties of Dex-Cool.
Inlet/Outlet Positioning: All LS engines have the same inlet and outlet position: on the passenger’s side of the engine. In most cases, the easiest solution is to purchase a radiator with passenger-side inlets and outlets. Because there is no mechanical fan in the way, running the upper return hose to the driver’s side is a pretty simple solution if the stock radiator has a driver-side upper mount.
The lower feed hose is more difficult to cross over to the driver’s side, depending on the distance between the engine and radiator. It is possible to have the inlets and outlets moved, but the expense is likely just as much as purchasing a new radiator.
Aftermarket Options: Each of the many aftermarket radiators has its own benefits. The easiest option is to order an off-the-shelf unit with the inlets and outlets as the manufacturer placed them. New aftermarket radiators that mount in the stock location are available for most popular cars.
You can also save some cash by purchasing a universal or “custom fit” radiator, typically sold in terms of dimension. For example, a four-core 20 x 16-inch radiator indicates a 20-inch-wide by 16-inch-tall radiator. Often, these radiators fit in the stock location using the stock or slightly modified mounting hardware and can cost as much as 30 percent less.
Custom Options: Ordering a custom radiator usually involves filling out a form and sending it in, along with a phone call or e-mail to discuss your specific needs. Griffin and Ron Davis, for example, have custom-build capabilities.
The ideal radiator configuration for a Gen III/IV is to have both outlets on the passenger’s side and a divider placed in the middle of the tank. However, converting to a crossover-style simplifies the installation.
Crossover-style tanks also ensure the coolant takes a longer route through the tubes as all the coolant must pass through the top rows then through the bottom, doubling the surface area the coolant must pass through. Radiators built in this manner cost between $600 and $1,200, depending on the size, configuration, and manufacturer.
A transmission cooler can be run in the radiator also, which keeps the transmission the same temperature without being affected by ambient temperature. This maintains a much more consistent transmission temperature over an external transmission cooler, which allows the transmission to run cooler in the winter and warmer in the summer. Gen III/IV engines do not tend to run hot, so if your LS is running much hotter than the thermostat installed, there’s a problem.
Mounting: Mounting the radiator below the engine is a common LS engine swap procedure that produces ineffective cooling and excessive heat. This is not an issue in most muscle cars and trucks, but on many other vehicles the radiator simply doesn’t have clearance to be mounted in a position higher than the engine. In this scenario, the engines tend to hold air pockets that lead to overheating.
There are a couple of solutions for bleeding air out of a cooling system. The first is to use the upper radiator hose to fill the engine. This allows the coolant to fill the engine from the top down, helping to force the air out. Once the upper hose overflows, connect it to the radiator and fill the remainder of the radiator. Fill the overflow tank to half full. Then the engine should be run with the heater at full blast and brought up to temperature. The overflow tank drains into the radiator. Once the cap is removed and more coolant is added, the overflow tank should remain at about one-quarter full when the engine is cool. If there is air in the system, the tank drains and more should be added until the tank remains at one-quarter full.
This does not always work. Jaguars That Run offers a specialized part that installs in line with the upper radiator hose. This piece contains a valve that allows the system to be purged of any remaining air.
Water Necks
The stock cast-aluminum water neck (also called the thermostat housing) points at a 90-degree angle toward the passenger’s side. This position works fine for many installations, but you may need a non-stock unit to accommodate a different radiator or chassis. There are several aftermarket alternatives to the stock cast water neck. Two such options are a straight unit (which is the best one for the early Corvettes), and a 360-degree swivel with either a 45-or 15-degree outlet.
This straight water neck is best for Corvette applications. Corvettes typically have less radiator clearance; the straight outlet provides a quick shot to the radiator with fewer bends. (Photo Courtesy Street & Performance)
These water necks make swaps a little easier. The 45-degree and 15-degree necks swivel 360 degrees. (Photo Courtesy Street & Performance)
AN conversion mounts like these from Trick Flow allow you to run braided hose to the radiator or water pump for a clean look. (Photo Courtesy Summit Racing)
Each water neck must match the water pump design, 1998–2003 and 2004–up. Since there is no mechanical fan to get in the way, you can easily run a lower radiator hose to the driver-side outlet on the radiator to prevent having to buy a new radiator.
Steam Lines
A unique design feature on LS engines is a pair of steam lines that route from the cylinder heads through the throttle body and onto the radiator. These lines circulate warm coolant through the throttle body to warm the intake charge on cold days and ensure that no air is in the cooling system. They must also be routed to the return tank on the radiator. There are three ways to accomplish this.
These fittings (in satin aluminum) are a perfect fit for the LS engine. (Photo Courtesy Blane Burnett)
The first is to use a traditional routing pattern and run a line from the driver-side cylinder head to the return tank on the radiator.
The second option is to drill and tap the top of the water pump with a 1/4-inch tap, install a 90-degree pipe fitting, and route the steam lines to the top of the water pump. This option certainly results in a cleaner look, but requires some additional work. As a bonus, if aluminum or stainless-steel hard line is used, the lines can be polished, adding some flash to a very utilitarian function.
The final option is to splice a “T” fitting into the heater hose, routing the steam line to it instead of to the radiator.
Steam Line Fittings
Steam lines are a necessary component of an LS engine swap. The problem is that they often look less than stellar with barbed fittings and rubber lines. A great alternative to the stock setup is to convert to AN-style lines. Aftermarket plumbing involves AN fittings, which were developed by the aerospace industry. Each AN size directly correlates to a specific outside diameter of metal tubing. Each size is listed as -X with the number after the “-” indicating a 1/16-inch increase in size. Therefore, a -3 fitting is 3/16 inch, -4 is 1/4 inch, and so on.
The passenger-side line connects with a T fitting, allowing the lines to be connected side to side and then to the radiator. (Photo Courtesy Blane Burnett)
Using a couple of 90-degree fittings, the driver-side steam line runs under the throttle body to the passenger’s side via braided Earl’s line. (Photo Courtesy Blane Burnett)
The AN conversion was performed on a Nissan 240SX LS3 swap. The Hinson conversion radiator in the Nissan 240 SX comes with steam line inlets welded to the tank and barbed hose fittings. The barbed fittings (left) were swapped out with the -6 AN replacement fitting (right). (Photo Courtesy Blane Burnett)
With the fitting threaded into the radiator, a straight Earl’s AN fitting was connected. All that is left is to cut a piece of braided hose and the steam lines are done. (Photo Courtesy Blane Burnett)
Choosing which components to use depends on your budget and the level of performance desired. Earl’s Performance Plumbing offers several different types of fittings and hoses to suit each system’s needs. The Ano-Tuff hard-anodized fittings resist corrosion and wear better than the more common red and blue anodizing. Swivel-Seal hose ends keep the hose from twisting and collapsing when assembling the lines in the car. The steam line adapters are from Trick Flow and have -6 male ends for the hose connections.
Electric Fans
An electric fan must be used because Gen III/IV (except for 5.3 1999–2005 Vortec) engines do not have provisions for a mechanical fan. There are many options for electric fans, both stock and aftermarket, and each requires custom fitting to the radiator.
For the budget-minded builder, reusing stock radiator fans is an inexpensive option. Most salvage yards include the stock fans (and maybe the radiator) when you buy a complete engine. Because the Gen III/IV platform is relatively new, there is plenty of life left in the fan motors. Of course, new fans have guarantees and can be configured exactly how they are needed.
Some 1999–2005 Vortec 5300 5.3-liter engines used mechanical fans like this. They can be used as is or converted to electric. If you convert them to electric fans, a traditional fan controller, such as the Flex-a-lite or rheostat device, must be used to turn them on as the ECM doesn’t have the wiring or the programming (which could also be added and an aftermarket harness used). (Photo Courtesy Street & Performance)
Electric fans are a must for most LS engines. Saving the original radiator and fans from the donor car is a suit-able option. This aftermarket fan from Flex-a-lite has the necessary shroud built in. (Photo Courtesy Flex-a-lite)
This staggered fan and shroud setup is an excellent choice for older cars, such as the Tri-Five GM cars. Older cars and trucks typically have square radiators, but adding two fans side-by-side can be tough. One fan might be sufficient, but the dual-speed fan control in the LS ECM allows for two fans to operate at different temperatures, yielding better cooling. (Photo Courtesy Flex-a-lite)
Electric fans require temperature sensors. This one simply snuggles between the tubes and fins. (Photo Courtesy Street & Performance)
The rheostat control can go anywhere, although close to the radiator is best. Once it is set, you don’t need to touch it again. (Photo Courtesy Street & Performance)
A more accurate thermostat installs directly in place of the petcock. This unit came from Street & Performance. (Photo Courtesy Street & Performance)
This is an example of a fan that does not use a shroud. Due to its design, air from the fan does not reach much of the radiator. The only time air passes through the radiator is when the car is moving. A shroud ensures more air passes the radiator when idling, an important feature for city drivers. (Photo Courtesy Street & Performance)
Flex-a-lite offers this electronic fan controller, which might be beneficial for engines running aftermarket controllers. This gives the driver control of the fan, rather than the ECM, so you can regulate operation and engine temperature. (Photo Courtesy Flex-a-lite)
Electric fans have many benefits over mechanical fans. Electric fans are set to run at a predetermined temperature, allowing the engine to reach operating temperature much faster. This improves fuel economy and reduces engine wear and oil contamination.
This Tech Tip is From the Full Book, LS SWAPS: HOW TO SWAP GM LS ENGINES INTO ALMOST ANYTHING. For a comprehensive guide on this entire subject you can visit this link:
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The electric fan can also operate when the engine is off, so the coolant in the radiator cools while the car is sitting. This helps keep the engine in its optimum temperature range during all driving conditions. How-ever, correct installation is essential. If electric fans are not installed correctly (with an electric fan shroud), they are not able to draw air through the entire radiator, and efficiency suffers.
When shopping for an electric fan, make sure to purchase one designed for high-performance engines and one that has a fan shroud for maximum efficiency. Some of the leading electric fans for LS engines are from Flex-a-lite, Griffin, AutoLocZirgo, and PermaCool.
Water Pumps
Factory water pumps are suitable for most performance applications with mechanical pumps, being the staple for high-performance street cars. However, electric water pumps have broken free of the stigma of being strictly for drag racing and can update the functionality of an LS swap.
One of the biggest benefits to an electric pump, beyond the horse-power savings, is the ability to wire a timer that circulates coolant through the engine after the engine is shut off, providing a consistent cooling rate. Meziere Enterprises’ LS engine pump is available with an idler puller, so the serpentine belt system can be retained, or without an idler pulley for race engines.
There are several flow ratings for electric pumps: from 20 to about 60 gallons per minute (gpm). For street applications, you want an extreme-duty motor that delivers as much GPM as possible, in the 45 to 55 range. The Meziere LS pump provides 55 gpm, as does the CVR electric LS pump.
1. The stock heater line fitting might not clear the suspension or frame in some installations. This can be rectified. (Photo Courtesy Street & Performance)
2. Using Vise-Grips and a hammer, tap the fittings out. 2 Using Vise-Grips and a hammer, tap the fittings out.
3. Remove the water pump and tap the fittings holes. The small fitting is the feed to the heater core; the larger one is the return. The small side is 3/8-inch and the larger is 1/2-inch thread. (Photo Courtesy Street & Performance)
4. You can then reinstall the pump. Don’t forget to clean it out; metal shavings are bad. (Photo Courtesy Street & Performance)
There are even options for a remote-mount electric pump, using a conversion kit from Moroso, which allows you to put an electric pump anywhere under the hood. The keys to an electric water pump installation are the heater hose fittings. Not all electric pumps come with all the ports required for hooking up heater hoses, so you have to work around that. Stainless-steel mounting hardware is included with this lightweight pump. Electric pumps clear camshaft belt drives, Jesel belt drives, and most blower drives, but spacers are necessary to clear distributor belt drives without the inlet fitting. The fitting must match the size of the lower radiator hose. The average amperage draw is 6 to 7 amps.
The biggest gain with an electric water pump is through elimination of drag. Just by dropping the drag of the pump’s operation from the engine, you can gain 15 hp, plus the cool factor goes way up.
Gauges
If you plan to run aftermarket gauges, you need to install an adapter into the block to convert the sending unit to SAE threads. The engine has a 12-mm plug on the rear passenger-side head that can be removed to provide the coolant temperature sender location.
Drill and tap for the pipe thread or fit a simple adapter to the head for converting from 12-mm to 1/8-, 1/4-, 3/8-, or 1/2-inch pipe thread. This needs to be done before installing the engine in the vehicle; otherwise it is extremely difficult to install the adapter.
1. These fittings accept AN -8 or -10 lines, depending on the size needed. AN fittings look nice on heater hoses. (Photo Courtesy Street & Performance)
2. In order to accurately measure the temperature of the coolant, you need to install a temperature-sending unit. This location at the back of the passenger-side head is the best place. This hole is threaded with a 12-mm plug. You need an adapter to match the sending unit. (Photo Courtesy Street & Performance)
3. This is what a 12-mm sending unit looks like. Most aftermarket gauges use NPT thread, thus the required adapter. (Photo Courtesy Street & Performance)
4. If you don’t install the sending unit before the engine, there may be a clearance problem. The only reason it could be done afterward on this 1969 Camaro was because the A/C box had been shaved. (Photo Courtesy Street & Performance)
5 . Another alternative is to use a heater hose coupler. This puts the sending unit in the upper radiator hose. This also serves as a good purge valve for getting any trapped air out the system. (Photo Courtesy Flex-a-lite)
Should it be too late to install the adapter, Flex-a-lite offers an inline adapter to be installed in the upper radiator hose. The adapter, designed to fit 11/2-inch and 13/4-inch hoses, has two 1/4-inch NPT threaded holes and a brass plug. This makes it easy to keep tabs on the coolant temperature.
Feature Vehicle: Gen III Jeep YJ
Photos courtesy Ken Wolkens
The Jeep Wrangler YJ is a venerable off-road vehicle, and most agree that through the years the Jeep Wrangler has delivered better off-road performance than any of its competitors. Whether it’s rock crawling, trail riding, or just going where most other 4x4s can’t, the Jeep has them all beat. Take it to the street, however, and the small, inline 4.0 6-cylinder engine does not deliver inspiring performance.
Engine swaps for the Jeep platforms have always been popular. The Buick V-6 is a classic Jeep swap, as is the traditional small-block Chevy 350. The most popular is the LS swap. Ken Wolkens is one of those Jeep owners who definitely needed a bit more power. Jeep enthusiasts tend to be of the “built not bought” mindset, using parts from other vehicles to make their Jeep better.
Built as a daily driver with the ability to go anywhere, Ken’s 1992 Jeep YJ uses many stock parts taken from salvage yards. The 5.3 4L60E transmission, power control module (PCM), wire harness, and drive-by-wire throttle pedal came from a 2005 Silverado with 24,000 miles on the odometer. To make the Gen II work with the Jeep, an NP231C transfer case with manual shifter and adapter from the transfer case to the transmission were sourced from a late-1980s to a mid-1990s Chevy S10 4×4. Rounding out the drivetrain is a D2 8.8 traction-lock rear axle with disc brakes from a 1995–2002 Ford Explorer.
The NP231 case was split, using the GM front half and the Jeep rear half and output shaft. This allowed Ken to use the Jeep speedometer output from the transfer case to drive the factory speedometer. The rest of the gauges were reused, keeping the Jeep oil and temperature sensors in the Vortec block.
The engine was mounted using a set of motor mounts from Advance Adapters, along with the factory transmission crossmember with a new hole for the 4L60E transmission. To make things easy, Ken cut a hole in the side of the transmission adapter for a vehicle speed sensor that tracks the vehicle speed through a reluctor wheel. This eliminates the need to program shift tables to the two-wheel-drive PCM.
Several exhaust manifolds fit the Jeep chassis. F-Body and C5–C6 Corvette LS manifolds work great, but truck manifolds do not. Ken used the C6 factory manifolds, which cleared the chassis perfectly.
The fuel system uses a Walbro GSS 310 255-liter-per-hour in-tank pump feeding a Corvette filter/regulator combo through a new 3/8-inch hard line to the engine. The Jeep fuel system line is a diminutive 5/16 inch, and is not capable of feeding an LS-series engine.
Even though the Jeep chassis is small, there were very few clearance issues. The main challenge with a Gen III/IV engine is clearance from the power steering pump to the lower steering shaft. There is only 3/4 inch, which is fairly tight. Ken used the stock Jeep hose, and adjusted the bends to fit. They worked, so nothing major needed to be done.
Another key issue was the radiator. Ken tried to adapt three radiators until he found one that worked. That one was a “custom-fit Jeep LS swap radiator” he found on eBay. It features a crossflow design with both inlet and outlet on the passenger’s side. The hoses were purchased at the local parts store using wire shapes as a guide.
With the details handled, the freshly assembled Jeep YJ has ample power. Passing on the highway requires a deft foot on the pedal to keep it from breaking the tires loose. With V-8 power and fuel economy that rivals the original 4-cylinder, Ken has a great-looking Jeep that can go anywhere and pass anything, including the gas pump.
Written by Jefferson Bryant and Posted with Permission of CarTechBooks
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