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Old 04-01-2010, 09:29 AM
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twistedsymphony twistedsymphony is offline
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Default Everything you wanted to know about an LS1 Swap

LS1 Swap... My PM box fills up all the time with questions, the other FAQs I've written are good for their specific topics but so far there hasn't been a single comprehensive guide to get people started and familiar with what's involved.
This is essentially my brain dump on the subject.

I'm going to try to cover everything you NEED to know to make an informed decision on whether or not this swap is for you, and if you want to go ahead with it give you the knowledge you need to get started. Read this and and if you still have any questions... ask away.

General Questions
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How Much does it cost?
This is often the first question people ask me, and it's a very reasonable question to want answered; however, there are many many different variations of this power plant and half a dozen viable options for each aspect of the installation. Though to give you the best tangible answer I can... with the cheaper engine types, if you hunt around for the right deals and are able to fabricate your own parts you can get a running swap in a 240 for about $3000 from the engine through materials and everything in between, I've seen it done and read the price sheet myself. This is not typical though and will require some planning, waiting, and a lot of elbow grease on your part. The most common swaps setups, using a kit, and fully functional (that means working AC too) will likely end up costing about $7000-$8000 at the end of the day, and that will still require a little hunting (mostly for the engine) and a little fabrication (mostly for the exhaust) but primarily off-the-shelf/bolt on parts. Of course on the upper end, the sky is the limit and you could easily spend 10s of thousands on an extreme setup.

How Long does it take?
Despite my car being out of commission for over a year if you've collected all the parts you need, with a few people who know what they're doing the swap could get done in 2 or 3 days time easily, and there are a few people out there who have done them that quickly too. Mine is taking much longer for a number of reasons that are really unimportant to this topic. Obviously if you're going the cheaper route that requires more fabrication it will take quite a bit longer than if you use a swap kit.

How much does it effect the Weight Balance/Handling?
The All Aluminum versions of this power plant attached to a 6-speed manual will only weigh about 140lbs more than a DOHC KA with an automatic. About 1/3rd of that weight increase comes from the transmission, also being a push-rod style motor most of the motor's weight sits significantly lower, and the shape of the motor allows it to be mounted a bit further back. Most people who have performed this swap have found that an LS1 equipped 240 actually has closer to 50/50 weight balance than one that was originally equipped with a KA, enough such that many who track their cars run equal spring rates front and rear. All in all the LS1 weighs significantly less than an RB25, or a 2JZ, though it is slightly heavier than a VQ swap or KA-T build.

What kind of power does it put down?
There are literally dozens of configurations of the GM LS series engine in stock form, add in the many common and readily available modifications and it's a pretty open ended question, but In general the most common configuration of the power plant will make about 300hp and 300ft-lbs of torque in stock form (read: no tuning, no power adders, that is the base bottom level power with an absolute minimal swap), there are factory configurations that make upward of 500hp, and the low end is about 280hp on the slightly smaller truck motors. More important than the peak output numbers however is the actual power curve. While the peak output might be similar to that of 2JZ, VQ, or a tuned SR, or KA-T unlike those motors it makes near peak torque several thousand RPMs lower than those engines.

That is a stock LS1 equipped Camaro, putting 300ft-lbs of torque to the wheels at 2500RPM, feel free to compare the area under the curve to your favorite engine configuration.

How far beyond stock can you push these motors?
VERY FAR. For a normally aspirated motor the GM LS series responds extremely well to modifications. For instance it's well documented that simply swapping out the factory cam on an LS1 or even a smaller 4.8 or 5.3L truck motor for an LS6 cam will at a strait 40hp to the wheels across nearly the entire power curve. It also returns respectable power gains from engine tuning, exhaust and intake mods, and there are numerous kits available for adding super chargers and or turbos, many of which will fit in a 240sx setup. There are built turbo setups putting down reliable power deep into the 1200+hp range.

How Difficult is it to tune?
General Motors was extremely kind, the ECU is essentially designed like a stand-alone unit and has nearly as much flexibility as one too. For a few hundred $$ you can pickup a copy of "HP Tuners" and completely re-map the factory ECU however you like, no modification to the computer are necessary, nether is any additional piggy-back hardware, just plug it in and tune. There are even cheaper options out there too such as "LS1 Edit", and there are services out there that you can mail your ECU to and they will mail it back tuned to your specs for a fee ranging anywhere from $50 to $500 depending on the company and the setup. Finding a local dyno-tuner familiar with tuning these power plants is quite easy as well. The factory computer is flexible and programmable enough that the only people I've ever seen running a 3rd party computer are those with dedicated track cars that have well over 5 figures worth of engine modifications.

Is it Street Legal?
This really depends on your state, but it's my understanding that as long as you keep all the emissions equipment in-tact then it should be legal on the federal level. I know there are CARB approved exhaust manifolds that worked and there are a few people in California who have passed emissions testing there without any slight-of-hand or bribery. On a whole as long as you hook up the OBDII port and are running Cats, and a muffler you should be ok. Many states require that the PCV, AIR, EGR, and EVAP systems remain in tact too, PCV, AIR and EGR are easily maintained (some versions of this motor weren't even equipped with EGR or AIR from the factory). EVAP is likely the hardest to maintain, though there are some people who have done a full EVAP swap too, I am not one of them.

Will I have to buy new Tools to work on this thing?
No, actually the Gen III and newer Small Blocks use all Metric bolts, you'd even be surprised by some of the Nissan parts simply bolt up the LS1 without any kind of adapter. There are specialty tools needed for certain tasks, like removing the power steering pump pulley, or aligning the timing chain cover. So far the few specialty tools I ended up needing, I was able to rent from my local Autozone without any problem.

Can I run a Carburetor instead of fuel injection?
The oldest of this engine series was made in 1997 so there was never any that came factory equipped with a carb, however Edelbrock makes a conversion kit that allow you to run these motors with a carb. They basically replace the intake plenum/throttle body and add a self-contained unit for managing spark. You'd probably dash your chances of passing your local emissions test but if carbs are your thing then yes it is possible.


CHOOSING AN ENGINE
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Which Engines Work?
"LS1" while the code for a specific Engine produced by General motors is often used as a generic term to describe any GM "LS Series" motor, or even more Generically any Generation III or Generation IV GM Small Block. Sometimes the term "LSx" is used but that's a misnomer as well since there is an actual "LSX" block sold by GM. In any case it doesn't matter because any Gen III or Gen IV GM Small Block will have the exact same external dimensions on the block, heads, valve cover, and all the exact same mounting points for the engine and transmission mounts. The only real external variation will come from the intake plenum, throttle body, oil pan and accessories but those can all easily be swapped out for more compatible parts. 1997 was the first year for the Gen III small Block and only available in the Corvette as the all aluminum "LS1", starting in 1998 the LS1 was also offered optionally in the F-Body cars (Camaro and Firebird) a few years later they started making iron block configurations available in pickups, Vans and even some FWD sedans. But the process of swapping one of these engines into your S-Chassis is the same regardless since they all have the same external dimensions.

Generation I small blocks (AKA the "Chevy 350" or the "SBC") and Generation II Small blocks (AKA the "LT1" or "LT Series" motor) while similar the Gen III and Gen IV motors DO NOT share external dimensions and are not compatible in the same way... they do make kits to swap these into an S-Chassis but that's a completely different topic and I will not be discussing it. Just to be clear: That wrecked 1997 Camaro V8 you found... it has an LT1 not an LS1... it's a completely different motor, I've had at least a dozen people contact me excited abut the mid-90s Camaro they found cheap... sorry but your princess is in another castle. The LT1 is a capable motor, but it's a completely different swap.

Which Engines Work Best?
Personally I feel that the LS1s out of an F-Body are the best candidates for a number of reasons:
  1. They have a cable based throttle (as opposed to drive by wire) which will hook up to the 240's throttle cable easily
  2. The Accessory configuration is known to fit in the 240's engine bay
  3. The Intake Plenum and Throttle Body are known to clear the 240's hood (somewhat dependent on mount kit you use, though it's typically not a problem)
  4. The Transmission options (both the 6 Speed Manual and 4 Speed Automatic) all fit and line up properly
  5. The Air Conditioning wiring is easily adaptable to the 240
  6. Information on the wiring is the most readily available compared to other variations of the motor.
The only things you will have to swap out on an F-body motor are the oil pan and the exhaust manifolds

2nd Best Choice would be an LS1 or LS2 out of either a Corvette or a GTO, these use Drive-By-Wire throttle bodies which can be used, though a lot of people prefer to convert back to a cable based throttle (it's personal preference really). The intake plenum and accessories on these motors have been proven to fit in the 240's engine bay. The Corvette's transmission is mounted in the rear of the vehicle so you will not be able to use a corvette transmission and instead should swap to one from an F-Body, Similarly the GTO's transmission has a different shifter assembly and the shifter sits several inches further back, the transmission can be used but you will either need to modify your tunnel to accommodate or swap the shift assembly out for one from an F-body. General wiring information is harder to come by but is available.

Which Setup is the Cheapest?
GM released 4.8L and 5.3L iron block variations of the Gen III/IV small block in a number of their pickups, These can be found regularly for well under $1000, I've seen 4.8L setups for $400 and 5.3L setups for $600 (compared to the $2000-$4000 price tag associated with most LS1/LS2 pull outs), however most of the time the accessory configuration will not be compact enough to fit in the engine bay, and the intake plenum/throttle-body will often sit too high up to clear the hood. wiring information is also more difficult to come by with these motors. They weigh quite a bit more than their all aluminum counter parts (80-160lbs more depending on what you're comparing) and the stock power output is in the 280hp range as opposed to the 300-350hp range you'd get with an all-aluminum variation, however many of the internals can be swapped and the iron block motors are often more desirable for forced-induction applications, and they're just as easily tunable/upgradable as any other GM LS-Series motor.

If you chose to go with a truck motor, plan on not being able to use the intake plenum or throttle body (they will likely be too tall) also plan on not being able to use the accessories or accessory brackets. Also since the AC is mostly controlled by the HVAC unit in these vehicles making it work in a 240 is often difficult with these engine variations. Knowing these things up front is key. I should note that the LS6 intake plenum is a popular swap for LS1 owners, so LS1 setups are usually fairly cheap and easy to come by, as for accessories, since most truck pull outs sold in scrap yards are used to replaced problem engines in similar vehicles as opposed to sports-car swap projects, they're often sold WITHOUT the accessories anyway to reduce the cost so if you can save some money buying it without the Alt and PS pump use that to your advantage so you can buy the F-body accessories and brackets... just make sure you get all the other important parts such as the harness, computer and sensors.

What are my Transmission options?
If you want a Stick shift the only transmission you should be considering is a T-56 6-Speed from an F-Body. GTO transmission work too (albeit with the caveat I mentioned earlier), 6-speed truck transmissions are extremely rare and I honestly don't know how well they'd work but I see no reason why they wouldn't bolt up. T-56s from other vehicles are incompatible due to input shaft and bell-housing parameters, Also older T-5 5-speeds and T-10 4-speeds are incompatible for the same reasons, they can all be modified to fit however the cost involved in making such modifications makes it not worth bothering. on it's own a complete T-56 setup will go for about $800-$1500 depending on the condition ($1500 being freshly rebuilt from a certified re-manufacturer), obviously it's a lot less expensive if you get a motor with the transmission already included.

If you want an Automatic the 4L60E from an F-body or GTO is the most common, and lines up in all the same places as the T-56, there are several others that will work though there are so many variables here if you're serious about going with an automatic you would be best served doing more in-depth research on the topic.

What Should my Motor Include?
When buying a motor you should be diligent in ensuring it has everything you need otherwise you'll be spending hundreds buying all the parts you're missing. Consider this a check list of what constitutes a "complete" setup
Bolted to the motor:
  • Intake Plenum/throttle Body
  • Fuel Rails/injectors
  • Coil pack/plug wires
  • Power Steering Pump
  • Power Steering Reservoir (unlike the 240 this is bolted right to the motor)
  • Alternator
  • AC compressor
  • PCV valve and lines
  • EVAP valve (only really important if you want EVAP)
  • EGR Valve (not all motors came with one equipped, vette motors don't have them, most others do)
  • Exhaust Manifolds/AIR vale and lines (not all came equipped with AIR, it should be obvious looking at the manifold)
  • Front O2 sensors
  • Starter motor
  • other engine sensors (too many to list, just look out for open holes, or harness plugs that don't go anywhere)

Not Bolted to the motor but should be included:
  • Complete uncut engine harness
  • Engine Computer Unit
  • TAC Module (needed for some drive by wire cars, some drive by wire cars don't have one. make sure it's the SPECIFIC TAC for needed for your engine)
  • Gas Pedal (needed for drive by wire cars, make sure it's the SPECIFIC pedal needed for your engine)
  • TAC/Pedal Sub Harness (needed for drive by wire cars, needed to hook the pedal and TAC module up to the rest of the harness)
  • MAF Sensor (usually attached to the intake, make sure you get the one meant for your motor)
  • IAT Sensor (usually attached to the intake, make sure you get the one meant for your motor

Not usually included but grab these if you can:
  • Decorative valve covers (the decorative plastic shields that go over the coil packs, not needed obviously but they look nice and they're worth some $$ even if you decide you don't want them)
  • Battery Wires (go from the battery to the starter, not vital, but grab them if you can)
  • AC lines that attach to the compressor, you'll need these to build your conversion lines
  • AC pressure sensor, one of the lines will have a 3 pin pressure sensor in it get the line and the sensor
  • AC sub-harness, a lot of motors put the AC compressor and sensor on it's own sub-harness, grab it if you can
  • Rear O2 sensors/Sub harness, not always needed and usually not included but valuable if you can grab them, and needed if you want a fully legal swap
  • EVAP equipment - located near the gas-tank I don't know much about it but it's expensive and you'll want to grab it if you plan on having a fully functional EVAP setup.
  • flywheel/clutch/pressure plate (chances are if you're buying your motor separate from the transmission this wont be included but if for some reason it's available, then good for you)

What Should my Transmission Include?
For a T-56 6-speed you'll want to ensure it has the following items
  • Bell-housing
  • vent tube
  • shifter
  • reverse sensor (on side)
  • vehicle speed sensor (VSS) (near rear)
  • reverse lock out solenoid
  • CAGS (aka: skip-shift) solenoid
  • Slave Cylinder (this is IN the bell-housing and wraps around the input shaft)

not needed but get it if you can:
  • output yoke (this will help keep the trans sealed and save you over $100 on the drive shaft)
  • shift knob (your Nissan one wont fit )

For an automatic, it varies depending on the model but you'll want to get the shifter and some models have a separate shift module and sub-harness beyond that you're on your own, there are some good writeups on LS1Tech.com that cover what you need depending on the transmission you're going with.

Where can I buy an Engine?
This isn't an SR or RB where you have travel out of state to an engine importer and hope they tested it, or buy one off of someone else after they ran out of funds and couldn't finish the swap... these motors are fairly easy to come by. checkout http://car-part.com and find scrap yards within driving distance, call them up and see if they've got the motor set you're looking for. The Camaro and Corvette pull outs are a lot less plentiful than the pickup stuff. I got my motor from Bow Auto Salvage in Bow NH, it was the only Corvette motor they had in stock, but they had 20+ truck motors ready to go. I should note that I also got the VIN from the vehicle my motor came out of and a 6 month warranty. And dealing with a local company, they're a lot less likely to sell you junk since you're easily capable of returning their product in person or taking them to small claims court, unlike some importer in Cali who can just neglect to answer the phone or respond to your emails should they do you wrong.

If you're fine with shipping the motor you'll have a lot more options, Check http://ebay.com, and http://ls1tech.com are probably your two best bets, though checking out forums specific to corvettes, Camaros, or GTOs, or any of the swap forums like http://silviav8.com or http://v8rx7forum.com sometimes have engines up for sale too.

If you're made of money there is also http://turnkeyenginesupply.com or buying a brand new crate motor direct from GM.

What Rear Differential Should I use?
A lot of people ask "What are you doing about the rear diff?" to them I typically reply "Nothing"... the factory R200 and R200V are strong and work perfectly fine. They can easily handle the power output from one of these motors. I should note that I've seen a few WELDED R200s grenade when mated to an LS1, but the open diffs and factory vLSDs seem to do just fine (perhaps the welding weakens them such that they break apart, or maybe it's something else altogether, just something I've seen happen a number of times). The Axles seems to be much more a point of concern than the diff is. but even still most don't have a problem unless they're seeing a lot of abuse.

The one "problem" with the rear diff is the Gearing. The Factory 4.09:1 gearing used in the 240sx is tall enough that on the T-56 6-speed first gear is useless and 2nd gear is often not even needed. For reference the F-body uses a 3.42:1 gearing for the 6-speed. A good option is to get the gears from a 1997-2001 Q45 which came in either a 3.54:1 or 3.69:1 ratio, which are much more in line with the factory F-body setup. The output shafts on a Q45 diff from this era are 5-bolt which will allow for beefier 1992-1994 J30 axles to be used. Swapping to this diff essentially kills 2 birds with 1 stone. I've heard that it is possible to put these gears in your original case when using a custom shim. A frequently sought-after setup is to use the Q45 gears with the helical-limited-slip element from an S15 diff.
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Last edited by twistedsymphony; 04-01-2010 at 03:08 PM.
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Old 04-01-2010, 09:30 AM
twistedsymphony's Avatar
twistedsymphony twistedsymphony is offline
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Default Re: Everything you wanted to know about an LS1 Swap

Mounting it up
--------------------------------------------------------
Headers
"Wait why aren't you talking about mounts?" you say... I'm not talking about mounts because the real issue with fitting one of these motors into your 240sx comes down to the headers, with the motor itself there is a lot of leeway with the placement but once you add headers your placement options are narrowed down to millimeters. Pick your headers FIRST, then once that is settled go with mounts that will place your engine properly based on the headers. It shouldn't matter if you go with short style headers, but if you go with long-tube style then it's VITAL to pick the headers first.

Short Headers
  • OEM C5 Corvette Headers: plenty of clearance on the passenger's side, the driver's side will need the flange cut off and an extension welded on to clear the steering column, these will likely work with just about any mount setup. You should be able to mount these headers without removing the steering column, though it's dependent on how you modified it.
  • OEM C6 LS2 Corvette Headers: Again plenty of clearance on the passenger's side, the drivers side will likely clear the steering column also, though it may be problematic depending on the mounts used. You should be able to mount these headers without removing the steering column.
  • "Block Huggers": a few companies make "block hugger" headers that are universal headers that sit tight against the block for use in engine swaps where space is tight. I've heard varying results with these some say they work without problem, other say they needed to be modified to clear the steering column. AFAIK There isn't much info available on this option.

Long tube Headers
  • Sikky: specifically designed for a 240sx swap, make sure you get the S13 or S14 version depending on your chassis. obviously designed to work with the Sikky mounts or of course a custom mount setup. You will need to remove the steering column to install these as the headers wrap around the column on both sides.
  • Hinson Supercars: specifically designed for a 240sx swap, make sure you get the S13 or S14 version depending on your chassis. obviously designed to work with the Hinson mounts but they also work with the Otto Factory mounts, or of course a custom mount setup. You will need to remove the steering column to install these as the headers wrap around the column on both sides.
  • Daft Innovations: specifically designed for a 240sx swap, make sure you get the S13 or S14 version depending on your chassis. obviously designed to work with the Daft Innovation mounts or of course a custom mount setup. despite the fact that they route around the outside of the steering column You will need to remove the steering column to install these.
  • Custom: getting custom headers made up is a viable option, particularly if you'd like to place the engine in the bay where you want it FIRST and then figure out the headers after. There are pre-made LS1 exhaust manifold flanges, and lots of companies that make collectors for those with the welding skills to build everything in between.

Engine Mounts
There are several shops that make custom mounts for this setup, in general they are part of a larger kit but I feel it's worth while discussing them outside the context of the kit.
  • Sikky 240sx Mounts - Part of the larger kit, these are CNC machined "single piece" style mounts available as either a solid mount or with urethane spacer. these have gone though several revisions at this point. Designed to work with Sikky Headers, should also work with OEM headers or custom, unknow if they work with others.
  • PX Racing 240sx Mounts - these are designed as two piece that connect together like a hinge. the individual flanges have a welded construction. It's unclear if PX Racing still makes these mounts. these are part of a larger kit. Your Mount choice should depend on which headers you're using. Not designed to work with any specific headers, should work with OEM or custom headers, unknown if they work with others.
  • Otto Factory 240sx Mounts - originally a single piece solid mounts that are welded together. the 2nd revision are 2 piece hinge style with a urethane cushion. Designed to work with Hinson Headers, OEM or custom, unknown if they work with others.
  • Hinson Supercar 240sx Mounts - single piece style, essentially use Corvette mounts with a special bracket to attach to the motor. these have gone through several revisions. Designed to work with Hinson headers, should work with OEM or custom, unknown if they work with others.
  • Daft Innovations 240sx Mounts - originally a 2 piece hinge style with a urethane cushion, eventually changed to CNC Machined single piece style mounts with a nylon spacer. These have gone through several revisions. Designed to work with Daft Innovations headers, should work with OEM or custom, unknown if they work with others.
  • Car Shop Universal Mounts - Universal mounts, these are a 2 piece hinge style mount with a urethane cushion. one side of each mount will need to be cut to length and welded to your engine cross member, easily the cheapest and easiest "custom" option available. Since they require cutting and welding, you should be able to use them with whatever header you like so long as you weld them in place with the headers installed for proper placement.
  • Custom Mounts - there are mounting plates designed to bolt to the engine block that you can build a custom mount off of. Others have used the corvette engine mount brackets and molded custom urethane wedges to connect it to the engine cross member. Since it's custom you can use them with whatever header you like so long as you design the mounts to place the motor properly for the headers.

Transmission Mount/Transmission Cross Member
Similar to the engine mounts many of the transmission cross members are part of a larger kit, most of the "kits" use an OEM replacement mount and a custom cross-member to use that mount with the chassis. Your transmission cross member choice should depend on which mounts you're using.

Due to the tight spaces it highly recommended that you get your headers ceramic coated and or heat wrapped, keep this extra thickness in mind when installing them.

Also, aside from the OEM headers most of the other options do not include flanges, unless you want to use a simple "slip fit" connection off of the header, keep in mind if you'd like to use a bolt on flange, v-band or other type of flange before you send it out to be ceramic coated, otherwise you'll have to get it re-done. It's also a good idea to test fit the headers before sending them out to be coated also, even if they're part of a kit the might require some minor tweaking to get right (I learned this the hard way).
  • Sikky 240sx Transmission Crossmember & Mount Designed to work with the Sikky Engine mounts, unknown if it will work with any other mounts.
  • PX Racing Transmission crossmember with OEM Mount Designed to work with the PX Racing engine mounts, unknown if it will work with any others.
  • Hinson Supercars Transmission Crossmember with OEM mount Designed to work with the Hinson mounts, unknown if it will work with any others.
  • Daft Innovations Transmission Crossmember with OEM mount Designed to work with the Daft Innovations engine mounts, unknown if it will work with any others.
  • Custom Transmission Crossmember Using an OEM or equivalent transmission mount building a custom cross member is trivial for anyone with basic welding skills. Essentially there are 2 bolt holes on either side of the tunnel and then a single bolt hole is needed to attach to the bottom of the mount. Essentially you need a flange for each side of the tunnel and then a beam across to connect the two. I've seen dozens of different designs for this, it's simple, be creative.

Oil Pan/Engine Cross Member
These two are grouped together because you really either need to modify one or the other or both.
  • OEM GTO Oil Pan with notched cross member - the Oilpan from the Pontiac GTO fits bets in a 240sx, however to make it fit the engine cross member needs to be notched, how much depends somewhat on the mounts you're using. Here is a comparison of a notched engine cross member to an unmodifed cross member:

    Every kit on the market with the exception of Sikky uses this setup and either provide you with a pre-modified x-member designed to work with their mounts, or require some kind of core exchange. It's unclear how well notched crossmembers mixed and matched between kits will work so it is not recommended. Anyone with basic welding and cutting skill should be able to perform this modification themselves easily. In general the a modified cross member ends up being stronger than an unmodified one due to the thicker metal used during reinforcement.
  • Modified OEM GTO Oil Pan - some people have opted to modify the GTO oilpan by cutting and welding a notch into the pan to clear the unmodified 240sx engine cross member, this is very much not recommended and is not only more difficult than notching the cross member but ends up being a less reliable solution... but a solution none the less.
  • Sikky Oil Pan - AFAIK the Sikky pan is currently the only custom pan designed specifically for use in a 240sx, most people consider it to be a more reliable and race ready option in comparison to the GTO pan. The Sikky pan is designed to be used with the Sikky mounts, and does not require any modification to the engine cross member. It has gone through several revisions those mostly minor changes to make it more friendly to daily driver applications.

DriveShaft
The drive shaft depends on 4 factors, the engine mounts/trans cross member used, your chassis (S13/S14), your transmission (6-speed or auto), and your differential (does it have an ABS sensor or not?). many kits include a proper shaft designed to work with their mounts, but ordering a custom shaft is often a cheaper option an one that ensures you get one designed to your needs. Its important to note that the F-body cars have a solid rear axle with a differential that moves up and down with the rear suspension, the yoke in the LS1 transmissions are designed to slide in and out to compensate for this. Since the 240sx has an independent rear suspension with a fixed position differential this mean that the slide yoke isn't really needed but will provide SOME forgiveness in terms of the shaft length.
  • Kit Shafts Sikky, Hinson Supercars, and Daft Innovations, all offer T-56 Drive Shafts designed to work with their kits, if you go with one of those make sure you notify them about whether you have an S13 or S14 and whether or not your Rear Differential has an ABS sensor or not, as these will change the required length. These are all 1 piece available in steel or aluminum. I would very much not recommend mixing and matching shafts from one kit to another as they are designed for the specific engine placement of the particular kit.
  • Custom Made Alternatively you can use a company like Shaft Masters or Drive Shaft Shop to make a custom drive shaft for you, simply inform them of the transmission, and differential you are using and measure the length and they will be able to produce you a shaft. If you're lucky enough to have a transmission that already includes a yoke you can save yourself quite a bit of money and are able to specify the size and quality of the materials and joints used as well. Generally prices are comparable or less than the shafts sold with the various kits. FWIW I paid $220 shipped for a 1 piece steel shaft from shaft masters balanced with heavy duty joints and flanges, which ended up being a higher quality and lower cost than if I had ordered one with my kit.
  • Modified OEM An even cheaper option is to obtain an OEM drive shaft from an F-body vehicle (or one equipped with a similar transmission) and have the shaft length modified and the differential flange swapped out to one that is compatible with your rear differential. typically you can obtain a used shaft for about $50 and it will cost roughly $50-$100 to have it modified.

Transmission Tunnel
No matter what kit your use your transmission tunnel will need to be hammered out to fit. In general it's really only the bell-housing that has a problem. When under your car you'll notice a pinch weld across the tunnel about 8 or so inches back from the firewall. do not not touch the weld itself from use a small hand-sledge to hammer out the tunnel from the weld all the way to the firewall. you'll want to hammer 1-1.5" deep, this will not damage any of the HVAC equipment in your car or anything else, there is plenty of room to grow. work slowly in rows from one side across to the other do the whole area before making a 2nd pass, or 3rd pass. Essentially you want to slowly stretch out the metal. Air hammers tend to be too aggressive and can crack the metal.

After hammering it out I cleaned and sanded the area down and sprayed it with a rust preventative paint.

Some people have opted to cut out this section of the firewall, and welded in plating further back. Personally I feel this is far more aggressive than is really necessary. I've also heard that banging out the tunnel is necessary for RB and other swap so if you've got additional concerns about this I'm sure you can look up some additional information.

Front Sway Bar
The stock front sway bar will hit the front of the GTO oil pan, it doesn't matter what kit you use. I'm unsure if the sway bar will hit the Sikky pan, I don't think it does but you may want to contact them to be sure. Obviously the front sway bar is important in any performance vehicle so here are some options to deal with it.
  • Sikky front Sway bar - Sikky makes a front sway bar with an extended front section specifically for this and similar swaps, it's not part of their kit and I'm not sure if its needed for their kit, but the sway will not only alleviate your clearance issues but it's also a substantial upgrade from the stock bar, stiffer overall with 3 mounting points for adjustment, and spherical end links. The kit costs $275 + shipping
  • Daft Innovations Sway Bar Spacers - Daft innovations make a spacer kit that will reposition the front of the bar about an inch lower and an inch further forward. I ordered these and didn't really like how tightly packed ait made everything, and how difficult it made getting to the various bolts in the front end (compounded by the fact I'm using a power brace) so I sold them, but the solution does work.
  • R33/A31 Front Sway bar - I've heard that these sway bars are direct bolt on and offer added clearance in the front, however I've never see anyone try it on a LS1 swap so it's still up in the air.
  • Oil Pan Modification - Some people have opted to notch the front of the GTO oil pan to clear the factory sway bar, much like notching the oil pan to fit the cross member it's not recommended ... but an option available none-the less.
  • Other Options - I've heard varying reports on the clearance of various aftermarket sway bars, though for every person that claims one works, there's another person who claimed the same bar didn't work for them. If you have access to one or more aftermarket bars then by all means try them out. Also I've heard that there are other spacers on the market for use with RB and other swaps so those might work also, but again I haven't heard any clear cut info on the success of these solutions.

Keeping ABS
If your car was originally equipped with ABS and you'd like to keep it then there is nothing with this swap that should stop you. However there are a few things you will need to modify to make it work.
  • ABS Module Bracket - The ABS module sits on a fancy looking bracket this has 2 legs, one short leg with 2 studs that bolts to the wheel well, and one really long leg that bolts to the frame rail. You'll need to cut off the really long leg as it will interfere with the passenger's side header. I pulled it off the car completely (yes, it can be done without removing the ABS unit), drilled out the spot welds, holding the long leg and then sanded and painted. The other leg is more than strong enough to hold the ABS module in place just fine.
  • Brake Lines - There are 2 brake lines that go pretty much straight down off of the ABS module, once the bracket has been modified these will need to be pushed toward the outside of the car, again to make room for the passenger's side header. if you have the tools to bend and flare your own line then this is a good option too.
  • ABS Wiring - Despite the fact that the ABS wiring is built into the main factory engine harness it really doesn't need to be. once I started pulling off the wrapping I found that I could completely separate the ABS (this includes the under dash connections, module connections, passenger's side sensor, and fuse box power) into it's own separate harness save for 2 wires, 1 is a ground (that can be tied to any ground) and the other is a Tach signal (that must tap the tach signal from the ecu), I recommend buying a 2 pin weather-pack connector to connect this to your modified engine harness and keep it separate.

Things to Remove from the Engine Bay
Before you drop in your motor there are a number of thing you should remove from the engine bay to ensure smooth sailing
  • Remove the Battery, bag and label the battery tie-down hardware
  • Remove the original radiator, and shroud and whatever fans might be attached to it, bag and label the radiator hardware
  • If you're keeping AC you can leave your condenser in the car, but remove the dryer and all of the AC lines, set these aside as you'll need them for your conversion lines. Label the plug that goes to the AC dryer, also label the plug that goes to your AC E-fan
  • Remove 100% of the original power steering equipment, this includes the reservoir and bracket and all the hard lines that decorate the front of the engine cross member and all the brackets they attach to. set the high pressure line aside, you may be able to reuse it, also remove the 2 hardlines on the back of the rack, you'll put them back on later, but it will make it easier to drop the motor in if you don't have to worry about hitting them.
  • The Power Steering pressure sensor is no longer needed either, label the plug so you know what it goes to though. Label the plug that goes to the AC compressor too. Also if you're swapping from an automatic there's a resistor bolted to the driver's side wheel well, you can junk that and label the plug so you know what it went to.
  • remove the factory air box equipment that hides behind the front bumper, it's not needed and now is as good a time as any to get rid of it (if it's still even in your car)
  • Remove all the original clutch equipment, set the clutch master aside since you'll need parts from it on the new setup, remove the clutch lines too, you wont be needing those.
  • Remove the brake booster line that went between the valve and the engine, this includes the section of hardline mounted to the firewall. The only thing left to the booster line should be a semi-circle of rubber line going from the booster to the valve.
  • If you're swapping to a drive-by-wire style throttle then remove the 240sx gas pedal and cable (if you're going with a cable throttle, you can leave this be)
  • Remove the fire wall damper (that stupid weight bolted to the firewall)
  • Remove all the original heater hoses, this includes the valve assembly and bracket for those of you with a 1995. (you can leave the cable that comes out of the firewall)
  • Remove the original engine harness, and set it aside for safe keeping, you'll need parts from this. For me I had to pull a bunch of HVAC equipment from under the dash and unbolt the ABS module to free up enough space to get it out. Make sure you disconnect all of the under-dash connections before you start yanking on it.
  • Remove all the original Cruise control equipment, Most of this is tucked up in the corner behind the passenger's side wheel, you wont need any of it so pull it out.
  • Remove all the fuel line equipment from the firewall forward, this includes the rubber lines, the Fuel Pressure Regulator, and all the hardline that go to the EVAP as well as the EVAP canister. Your fuel lines might still have some pressure in them so it might be best to leave some of the rubber lines in place and get a bolt that you can thread in to plug the line should it be a problem.
  • Remove the lower engine harness and transmission sub-harness if it's still attached, set these aside for safe keeping as you'll need some parts from them later.
  • If you have an S14 SE there is a mini fuse box off the side of the main fuse box, there's a clip that holds this in place, unclip it as you'll need the extra room
  • If you're going with long-tube headers, take the opportunity to mark where the steering column bolts to the rack and remove the column (remove the bolt closest to the rack COMPLETELY before pulling the column out)

Other Engine Bay Considerations
Other stuff you should take advantage of while your engine bay is free of an engine.
  • If you're swapping from an auto to a stick shift, now is a great time to drill out the holes in the firewall and mount the pedal. Also a good time to swap the brake pedal too if you're doing that since you're probably going to remove the column, or at very least it will be easy to)
  • If you're removing your ABS now is a great time to swap all the lines over and swap over the equipment
  • Install some Aftermarket Urethane Steering Rack Bushings... WAY easier when there is no engine in the bay
  • Any sort of rust repair or engine bay painting... great opportunity
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Last edited by twistedsymphony; 04-01-2010 at 03:07 PM.
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Old 04-01-2010, 09:31 AM
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Default Re: Everything you wanted to know about an LS1 Swap

Support Systems
--------------------------------------------------------
Fuel Pump
You will need to swap your pump, the Walbro 255lph is a popular choice, any other comparable pump that you might use for a high horsepower RB or SR setup would work fine as well (if you're running a carb setup, you'll need a completely different style pump)

Fuel Lines/Filter/Regulator

Radiator & Fan

Radiator Hoses and Steam Lines

Heater Hoses

Power Steering

Exhaust

Air Conditioning
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Old 04-01-2010, 09:32 AM
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Default Re: Everything you wanted to know about an LS1 Swap

Adapting the Wiring
coming Soon
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Old 04-01-2010, 10:58 AM
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Reserved for future use

this will take me a while to finish so feel free to start posting up any questions you think I should answer or topics I should be covering... or if I got anything wrong or other errors let me know so I can fix it.
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Last edited by twistedsymphony; 04-01-2010 at 11:04 AM.
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Old 04-01-2010, 11:14 AM
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Default Re: Everything you wanted to know about an LS1 Swap

This is awesome. Just yesterday I was toying with the idea of doing this swap and ditching the very finicky sr20. Its hard to win a race when you cant finish. This will help me a ton. I really didn't know the difference in the motors. I was leaning towards the iron block just to save money and dealing with the weight in other ways.
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Old 04-01-2010, 12:10 PM
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Default Re: Everything you wanted to know about an LS1 Swap

there are a few resources online that attempt to compare the differences of the different variants however the best advice I can give you is to pickup a book titled "How to Swap a GM-LS Series Engine into just about anything"

it's a decent resource (I definitely learned a few things that I've never seen covered online) but perhaps the best part is that it spends half a page on every single LS engine variation from 1997 through 2008 which vehicles you can find them in, what their differences are, etc...

if you're going for a track car the iron block is a good budget choice... particularly the 6.0L iron blocks
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Old 04-01-2010, 03:58 PM
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Default Re: Everything you wanted to know about an LS1 Swap

6.0L huh. Oh boy that would be fun. Toss in some cams and I bet it would make up for the extra weight lol.
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Old 04-01-2010, 06:11 PM
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Default Re: Everything you wanted to know about an LS1 Swap

they make an aluminum 6.0L too... that's what the LS2/LS3 are

the LS7 is a 7.0L and makes 505hp/475ft-lb torque no super charger or anything
http://www.corvettemuseum.com/specs/2006/LS7.shtml

you can get a brand new one fully dressed for $15K which honestly, is dirt cheap when you consider the damn things are hand built buy a single engine builder.
http://www.jegs.com/i/GM%20Performan...0002/-1?CT=999
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Last edited by twistedsymphony; 04-01-2010 at 06:16 PM.
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Old 04-07-2010, 07:58 AM
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Default Re: Everything you wanted to know about an LS1 Swap

new swap kit just announced a few days ago: http://www.silviav8forums.com/forum/...t=2341&start=0

it looks like a really solid option.
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