Nissan 240SX SR20DET Engine Swap Guide Part 1

October 22, 2011 | DIY Tech | Tune2Win | Comments (0)

By now there are probably almost as many SR-powered 240’s running around North America as there are KA-equipped ones. So why would we bother providing a step-by-step guide on such a popular swap? Simply put, because there are still just as many people (if not more) performing this swap as there were 2 or 3 years ago.  We’ve gone through the painstaking trouble of taking photos of every step to ensure that this guide is as comprehensive as possible. But just like with anything mechanical, there will be some slight differences between cars, engines and installations methods. We aren’t saying this guide is the be-all and end-all of SR swap instructions, but we’re confident it’s one of the more detailed versions on the internet. 

Just like you may be planning, this swap was performed in a normal house garage on jack stands with a decent set of hand tools. As the pictures will prove, we spent from morning to night wrenching on our S14 and were able to get this swap done in a weekend. The key is to take your time, especially if this is your first swap. Rushing matters will only result in mistakes being made that will come back to haunt you once you’re ready to turn the ignition key.

So why the SR20 and not an RB, 2J, or even a GM V8 swap? Cost. We all know that most of us who own 240’s are on a budget, trying to make our car as fast as possible without putting too severe a beating on the pocketbook. Simply put, the SR20 swap is the best bang for the buck swap available for the S-chassis. 

The second reason is simplicity. The SR20 plus a simple wiring job is essentially all you need to bolt this engine into your 240. Unlike the other swaps, no custom mounts or drive shafts are needed. This sucker just fits perfectly, as you’d expect from a drivetrain that was the factory choice for the JDM version of this vehicle.

As for sourcing a motor, do your homework and find a reputable place to buy your engine set from. The lure of cheap motors usually comes at a cost of performance when you finally get it fired up (if it even fires at all). If the deal is too good to be true then it usually is. Be sure to inspect your motor set by checking the plugs, pulling the valve cover, and spinning the turbo among other things.

Without further ado, here’s our step-by-step guide on how to install a bone stock S14 SR20DET into a 1995 S14 chassis 240SX. If you are installing it into a 97-98 chassis or even an S13 it will be almost the same, other than a few wiring details.

PART 1

In our case, we were actually able to buy a whole JDM S14 that was wrecked in an accident (in Canada you can import JDM cars that are 15-year-old or more), so I parted the car out and kept the motor for our swap. The real advantage to this was that I had a chance to drive the car and do a compression test on the motor.

The engine was completely stock, which is exactly what we were looking for. This way we knew it hadn’t been tampered with.

This was our workspace for the swap. As you can see it’s nothing too fancy. We did have an air compressor, which helps speed up the removal of some of the bigger bolts, but it isn’t a requirement. By the way, you’ll have to excuse the mismatched paint on our S14. We were just in the process of installing a Kouki style front end.

CLUTCH

The first order of business is to separate the engine from the transmission to check and see if the clutch is good. Chances are the clutch is old and beat up from years of abuse in Japan. Even if it isn’t, this is still a good time to install a better clutch since the OE unit can’t handle much more power than stock.

We opted for a Fidanza Stage 2 clutch which we thought would be adequate for this application. As it turns out the pressure plate was too soft and the clutch would slip under stock boost. It was replaced with an Exedy stage 1 clutch shortly after.

Having the flywheel resurfaced is a necessity when changing the clutch. A local shop can do it for around $40-$50 dollars.

Changing the pilot bushing bearing? is also a good idea. It’s cheap insurance against the stress that’s placed on the input shaft when the pilot bushing is worn out.

Here’s a close up of the new bushing installed.

Always use some type of thread sealer on the flywheel bolts. If they back out then you’re going to have a serious engine failure on your hands, not to mention the chance of a flywheel coming through the firewall. Ouch!

We screwed all the bolts in finger tight before beginning the torque sequence.

In a star pattern, torque the bolts to 94 - 101ft-lbs with a torque wrench.

If you have problems with the flywheel turning as you are torquing the bolts, you can use a large pry bar and wedge it between the engine and flywheel as shown.

Before installing the clutch, ensure the flywheel surface is clean by spraying some brake cleaner on it and giving it a good wipe with a clean shop towel.

Slide the clutch into place with the supplied clutch alignment tool.

Install the pressure plate bolts.

Snug them down in a star pattern following this torque procedure: First tighten all bolts to 7.2 - 14 ft-lb then tighten again to 16 - 22 ft-lb.

THROW OUT BEARING

Next up is removing the throw-out bearing and replacing it with a new unit. If you pull on it the rear clip will pop off the arm and the bearing will slide off.

This is what it will look like.

The bearing is press fit onto the housing. We used a large socket to hammer it off.

This is what it looks like separated. You can toss the old throw-out bearing in the garbage.

Using an even bigger socket we lightly tapped the new throw-out bearing into place.

To slide the bearing back into place you’ll have to fiddle with the rear clip and fork a bit but eventually it will snap into place.

Before you reinstall the transmission onto the engine, make sure to lube up the input shaft with grease. This will allow it to slide into the center splines on the clutch disc much easier.

Slide and wiggle the transmission into place, it may take a couple tries to get the splines to line up with the clutch. Tighten the transmission bolts up to 22-29ft-lbs.

NISMO ENGINE & TRANS MOUNTS

This upgrade really isn’t necessary but we highly recommend it. The old SR motor mounts are 10+ years old and are likely to have a lot of play in them. If you are building a car for any type of performance then stiffer motor mounts will benefit you. Less engine movement means more of the available power is going to be delivered to the rear tires instead of being wasted by excessive engine and drivetrain motion.

You can see that the Nismo mount isn’t that different from the OE unit. This is good because it’s still very civil for daily driving yet gets rid of a lot of the shake that old stock mounts allow.

Here is the rear Nismo transmission mount being installed. No sense in doing just the engine mounts. Do all three.

The mounts come off with one nut and are easy to change while the engine is out. Once the engine is in the car it’s a nightmare trying to change these mounts!

GT SPEC TURBO OULET

The last upgrade we decided to do was the 02 housing turbo outlet. This is another piece that is easy to get at with the engine out but when it’s installed it’s a huge pain to change. The bigger outlet enhances exhaust flow, which as we all know is key to making power on any turbo engine.

Remove the heat shielding around the outlet.

Now you can remove the five bolts that hold the outlet on. You’ll have to use a wrench to get at the one nut that is tucked close to the housing.

It should just slip right off.

Have a quick look at the turbine wheel on the turbine for any damage. If you see some it may be a good idea to replace the turbo.

We also had a brand new Denso 02 sensor laying around, so we decided to replace the old factory unit with this one.

It’s smart to transfer the old studs from the OE housing to the new one. If you use two nuts and tighten them together then use a wrench on the inside nut the stud should come out.

However, sometimes it just too rusted so it may not budge. We tried some heat to help it on its way and it still didn’t want to come loose. Bolts can work almost as well so we gave up on the stud idea and used bolts to hold the downpipe up.

Just like you took the stock one off, reverse that to install the new turbo outlet.

Voila, the heat shields are back on and we’re done working on the motor.

Go to Part 2: KA Removal and Prep

October 22, 2011 | DIY Tech | Tune2Win | Comments (0)