Final Some truth to the matter rb in s14's
02-20-2007, 07:49 PM
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Join Date: Oct 2006
Location: Renton WA
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Final Some truth to the matter rb in s14's
I have been on this forum for awhile now and keep asking for help on a more in depth look at the swap with no response but, get a shaft, blah blah blah and look on the forum the answers are here. Also considering its hard to ask a question without getting flammed, i guess everyone is supposed to be an expert. Well for all those out there like me here u go this is wat i was looking for hopefully this will help u out too. I set out upon the world wide web to look for some more information to bring to this wonderful site. I found at http://www.sportcompactcarweb.com/te...0sx/index.html
!!the complete article is there i took out some stuff becuase of message length.
Picking the Engine
An R33 Nissan Skyline GT-S 2.5t. A complete front clip is usually recommended, because the many wiring and plumbing details are easier to work out when the original engine compartment is there for reference. Also, depending on which engine mounts you choose to use, the Skyline front crossmember may be needed.
As a bonus, most front clips come with big, four-piston front brakes which will bolt onto a 240 SX if you have the five-lug hubs (or you can have the rotors redrilled to four-lug). The clip for this swap came from Night Szevyn Racing in Seattle.
Engine Removal and Prep Work
If your car has air conditioning, have the system evacuated before removing the engine. Venting freon to the atmosphere is illegal and will give people in Australia sunburns. If you plan on keeping the A/C, it will be easiest to keep the Skyline pump and have the new hoses made to connect the pump to the 240SX air conditioning system. Any A/C shop should be able to handle this by simply crimping new hoses onto the fittings from the Skyline pump.
Next, Remove it all
The easiest way to remove the drivetrain is from below, crossmembers and all. To do this, remove the bolt holding the steering shaft U-joint in place, unbolt the lower control arms and swing them out of the way, remove the front anti-roll bar and support the car on something other than the crossmember (the frame rails under the footwells will work). Support the engine with an engine hoist and the transmission with a floor jack.
Now, unbolt the engine and transmission crossmembers from the car, and lower the driveline to the floor. If you have a low-profile furniture dolly, you may want to set the engine on that.
Hook the engine hoist to the lower radiator core support and lift the nose of the car high enough that you can slide the engine out from below.
The stock fuel pump, if it's in good shape, may support the stock RB25 for a while, but a tired pump or an increase in boost could be trouble. A Q45 or 300ZX pump will do the job unless you have enormous power goals, in which case, you better be able to figure out fuel pumps on your own.
If you bought an entire front clip, you'll have to pull the RB25 from the clip as well. The belt-driven cooling fan from the Skyline won't fit the smaller 240SX engine compartment, so go ahead and remove it, along with the fan shroud. While you have the engine on the ground, this is a good time to consider replacing the clutch. The R33 Skyline GT-S 2.5t uses a 240-mm clutch with the same critical dimensions as the non-turbo Z32. A stock Z32 clutch will work, though it may be a little weak if you crank the boost. Jim Wolf Technology also has upgraded units that should handle more than 500 lb-ft of torque. The R34 versions of this engine used a pull-type clutch. You're on your own finding replacements for that one.
Mounting the Engine
Now you have to start making decisions.
If you're eating rice and beans just to pay for the engine, you'll be glad to hear it will bolt in using the R33 crossmember and fit well enough to get you on the road, but the engine will sit a little higher and a little farther forward than is ideal. Some of the hood bracing will have to be removed to clear the throttle body and blow-off valve flange and the shifter will sit about an inch and a half forward of the center of the shifter hole in the floor. The cast-iron downpipe will also interfere with the steering shaft, and the transmission crossmember won't quite bolt in properly. The severity of the steering shaft interference varies from car to car, depending on how all the manufacturing tolerances stack up, how worn out the mounts are and how bent the car is. In some cases, you may simply need to notch the downpipe a bit, in others, you may need to fabricate a new one. Just remember, the engine will move around when it's making torque and from cornering loads, so give the steering shaft some room. You don't want the steering locking up in a moment of hard acceleration and cornering.
Both the Skyline and 240SX crossmembers are designed to accept left- or right-hand-drive steering racks, so putting your old rack on the Skyline crossmember is simple. The power steering return line from the 240SX is aluminum and is designed to act as a power steering cooler by running back and forth across the front of the crossmember before returning to the reservoir.
Crossmember
You have three choices here. Either skip the cooler and run a new piece of power-steering hose from the rack directly to the reservoir (not recommended), install a real cooler, or grab the old aluminum lines with both hands and bend them until they fit. You'll need to add some adell clamps, zip-ties, or bits of bailing wire to hold the lines in place if you take the third option.
The Skyline's transmission crossmember is nearly identical to the one on the 240SX, but the transmission is longer, so it won't line up with the holes in the car. Again, you have options.
If this is just a show car, file the bolt holes on the transmission mount so it can slide forward on the transmission a half inch or so. Then shove on the flimsy, flexy transmission mount until the center hole on each side of the crossmember (originally a drain hole, not a bolt hole, but it will work) lines up with the rearmost mounting hole on the car. Bolt it on with one bolt on each side (it's supposed to have two) and go polish something. Oh, sure, the top of the transmission will be jammed up into the top of the tunnel, but that won't really matter on a show car.
Now, if you actually intend to use that big turbo six to make power, two bolts aren't enough, and having the transmission hitting the tunnel won't do. We realized both the height and mounting hole shortage could be addressed with a simple pair of billet-aluminum spacers designed to lower the transmission and relocate the holes simultaneously. He's going to make the spacers.
Finally, if you want the engine to sit low enough to clear the hood bracing, the shifter to sit where it used to, the steering shaft not to hit the downpipe and everything to bolt in properly, there's a third option. McKinney Motorsports make engine mount kits that move the engine down and back about an inch and a half. In addition to making everything fit better, moving the drivetrain, which weighs about 650 pounds, shifts the center of gravity in exactly the right direction. This is also the ideal option if you have an engine, transmission, harness and ECU, but no front clip.
Driveshaft
The RB25's transmission is slightly longer, and the output shaft slightly larger than the 240SX, so a new driveshaft is needed. If the Skyline's driveshaft yoke was included in your clip, slide it into the transmission and shove it all the way forward. Then bolt the stock driveshaft to the differential and let it hang. Measure the distance from the center of the U-joint on the diff to the center of the U-joint on the back of the transmission and--this part is important--subtract 1 inch to allow for driveline movement. Take all the pieces to a driveline shop and tell them "I want this yoke (Skyline) and this rear U-joint (240SX) on a one-piece driveshaft this long (your measurement)." Then give them money (probably a few hundred bucks). If you don't have the Skyline yoke, you can use one from a twin-turbo Z.
If you try to shorten the stock two-piece driveshaft instead of making a new one-piece, it might work. Or the angle of the short front section of the driveshaft may get too steep, leading to a driveshaft failure. It's your choice. If you're using McKinney's mounts, the shop also offers a shortened one-piece driveshaft with larger U-joints that's ready to install.
An RB20DET uses the same size driveshaft yoke as the 240 SX, and is reported to accept the KA24 driveshaft without modification.
Cooling
The stock 240SX radiator has nearly the same hose locations as the Skyline radiator, though the KA24DE uses a smaller hose than the RB25DET. Making it fit can be as simple as trimming a little from the ends of the Skyline hoses and using an adaptor to fit the 1.75-inch Skyline hose to the 1.75-inch 240SX radiator. Keep an eye on the temperature gauge, as the 240SX radiator was never intended for the thermal load a Skyline engine will put on it. In the long run, an upgrade, such as the Koyo aluminum radiator in our Project Silvia, may be in order.
Depending on your mounting choice, the belt-driven fan may not fit, so you'll have to switch to electric fans. The Flex-a-lite Twin Line 320 dual 10-inch fans we used on our Project Silvia (June 2003) have been working well and would be a good choice for this application as well.
The S14 heater hoses are also a nearly perfect fit, sliding onto the RB25DET with only minor trimming.
Fire it up and go look for Supras.
!!the complete article is there i took out some stuff becuase of message length.
Picking the Engine
An R33 Nissan Skyline GT-S 2.5t. A complete front clip is usually recommended, because the many wiring and plumbing details are easier to work out when the original engine compartment is there for reference. Also, depending on which engine mounts you choose to use, the Skyline front crossmember may be needed.
As a bonus, most front clips come with big, four-piston front brakes which will bolt onto a 240 SX if you have the five-lug hubs (or you can have the rotors redrilled to four-lug). The clip for this swap came from Night Szevyn Racing in Seattle.
Engine Removal and Prep Work
If your car has air conditioning, have the system evacuated before removing the engine. Venting freon to the atmosphere is illegal and will give people in Australia sunburns. If you plan on keeping the A/C, it will be easiest to keep the Skyline pump and have the new hoses made to connect the pump to the 240SX air conditioning system. Any A/C shop should be able to handle this by simply crimping new hoses onto the fittings from the Skyline pump.
Next, Remove it all
The easiest way to remove the drivetrain is from below, crossmembers and all. To do this, remove the bolt holding the steering shaft U-joint in place, unbolt the lower control arms and swing them out of the way, remove the front anti-roll bar and support the car on something other than the crossmember (the frame rails under the footwells will work). Support the engine with an engine hoist and the transmission with a floor jack.
Now, unbolt the engine and transmission crossmembers from the car, and lower the driveline to the floor. If you have a low-profile furniture dolly, you may want to set the engine on that.
Hook the engine hoist to the lower radiator core support and lift the nose of the car high enough that you can slide the engine out from below.
The stock fuel pump, if it's in good shape, may support the stock RB25 for a while, but a tired pump or an increase in boost could be trouble. A Q45 or 300ZX pump will do the job unless you have enormous power goals, in which case, you better be able to figure out fuel pumps on your own.
If you bought an entire front clip, you'll have to pull the RB25 from the clip as well. The belt-driven cooling fan from the Skyline won't fit the smaller 240SX engine compartment, so go ahead and remove it, along with the fan shroud. While you have the engine on the ground, this is a good time to consider replacing the clutch. The R33 Skyline GT-S 2.5t uses a 240-mm clutch with the same critical dimensions as the non-turbo Z32. A stock Z32 clutch will work, though it may be a little weak if you crank the boost. Jim Wolf Technology also has upgraded units that should handle more than 500 lb-ft of torque. The R34 versions of this engine used a pull-type clutch. You're on your own finding replacements for that one.
Mounting the Engine
Now you have to start making decisions.
If you're eating rice and beans just to pay for the engine, you'll be glad to hear it will bolt in using the R33 crossmember and fit well enough to get you on the road, but the engine will sit a little higher and a little farther forward than is ideal. Some of the hood bracing will have to be removed to clear the throttle body and blow-off valve flange and the shifter will sit about an inch and a half forward of the center of the shifter hole in the floor. The cast-iron downpipe will also interfere with the steering shaft, and the transmission crossmember won't quite bolt in properly. The severity of the steering shaft interference varies from car to car, depending on how all the manufacturing tolerances stack up, how worn out the mounts are and how bent the car is. In some cases, you may simply need to notch the downpipe a bit, in others, you may need to fabricate a new one. Just remember, the engine will move around when it's making torque and from cornering loads, so give the steering shaft some room. You don't want the steering locking up in a moment of hard acceleration and cornering.
Both the Skyline and 240SX crossmembers are designed to accept left- or right-hand-drive steering racks, so putting your old rack on the Skyline crossmember is simple. The power steering return line from the 240SX is aluminum and is designed to act as a power steering cooler by running back and forth across the front of the crossmember before returning to the reservoir.
Crossmember
You have three choices here. Either skip the cooler and run a new piece of power-steering hose from the rack directly to the reservoir (not recommended), install a real cooler, or grab the old aluminum lines with both hands and bend them until they fit. You'll need to add some adell clamps, zip-ties, or bits of bailing wire to hold the lines in place if you take the third option.
The Skyline's transmission crossmember is nearly identical to the one on the 240SX, but the transmission is longer, so it won't line up with the holes in the car. Again, you have options.
If this is just a show car, file the bolt holes on the transmission mount so it can slide forward on the transmission a half inch or so. Then shove on the flimsy, flexy transmission mount until the center hole on each side of the crossmember (originally a drain hole, not a bolt hole, but it will work) lines up with the rearmost mounting hole on the car. Bolt it on with one bolt on each side (it's supposed to have two) and go polish something. Oh, sure, the top of the transmission will be jammed up into the top of the tunnel, but that won't really matter on a show car.
Now, if you actually intend to use that big turbo six to make power, two bolts aren't enough, and having the transmission hitting the tunnel won't do. We realized both the height and mounting hole shortage could be addressed with a simple pair of billet-aluminum spacers designed to lower the transmission and relocate the holes simultaneously. He's going to make the spacers.
Finally, if you want the engine to sit low enough to clear the hood bracing, the shifter to sit where it used to, the steering shaft not to hit the downpipe and everything to bolt in properly, there's a third option. McKinney Motorsports make engine mount kits that move the engine down and back about an inch and a half. In addition to making everything fit better, moving the drivetrain, which weighs about 650 pounds, shifts the center of gravity in exactly the right direction. This is also the ideal option if you have an engine, transmission, harness and ECU, but no front clip.
Driveshaft
The RB25's transmission is slightly longer, and the output shaft slightly larger than the 240SX, so a new driveshaft is needed. If the Skyline's driveshaft yoke was included in your clip, slide it into the transmission and shove it all the way forward. Then bolt the stock driveshaft to the differential and let it hang. Measure the distance from the center of the U-joint on the diff to the center of the U-joint on the back of the transmission and--this part is important--subtract 1 inch to allow for driveline movement. Take all the pieces to a driveline shop and tell them "I want this yoke (Skyline) and this rear U-joint (240SX) on a one-piece driveshaft this long (your measurement)." Then give them money (probably a few hundred bucks). If you don't have the Skyline yoke, you can use one from a twin-turbo Z.
If you try to shorten the stock two-piece driveshaft instead of making a new one-piece, it might work. Or the angle of the short front section of the driveshaft may get too steep, leading to a driveshaft failure. It's your choice. If you're using McKinney's mounts, the shop also offers a shortened one-piece driveshaft with larger U-joints that's ready to install.
An RB20DET uses the same size driveshaft yoke as the 240 SX, and is reported to accept the KA24 driveshaft without modification.
Cooling
The stock 240SX radiator has nearly the same hose locations as the Skyline radiator, though the KA24DE uses a smaller hose than the RB25DET. Making it fit can be as simple as trimming a little from the ends of the Skyline hoses and using an adaptor to fit the 1.75-inch Skyline hose to the 1.75-inch 240SX radiator. Keep an eye on the temperature gauge, as the 240SX radiator was never intended for the thermal load a Skyline engine will put on it. In the long run, an upgrade, such as the Koyo aluminum radiator in our Project Silvia, may be in order.
Depending on your mounting choice, the belt-driven fan may not fit, so you'll have to switch to electric fans. The Flex-a-lite Twin Line 320 dual 10-inch fans we used on our Project Silvia (June 2003) have been working well and would be a good choice for this application as well.
The S14 heater hoses are also a nearly perfect fit, sliding onto the RB25DET with only minor trimming.
Fire it up and go look for Supras.
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