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My 1UZ 280zx swap


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Here are a couple of pics of where I am up to with the exhaust (please ingnore all the wire and everything that I used to position things). Trying to squeeze two cat converters into the tunnel while keeping ground clearance has been fun..... I know ideally they should be as close to the engine as possible (for good emissions performance anyway), but the only place they were going to fit is just after the transmission. I've tried to make sure than the exhaust doesn't come down below the chassis rails, so that I don't have to worry about ground clearance so much.





Now the next issue that I have run into is the diff. I'm going to use an R200, although as the car was originally automatic, it only has the R180. I got a R200 diff from someone in a local club and was told that it was in good condition. Although after opening it up that doesn't really seem to be quite so accurate. The pics were only taken on a phone so sorry about the quality.










As you can see the centre is pretty stuffed, although that doesn't worry me as I'm installing a helical (OBX type) LSD. Something has let go in the centre and it has rubbed on the end of the pinion and one spot on the ring gear. At the moment the diff shop that was going to install the centre thinks that it should be fine to use the pinion and ring gear, but they can't guarantee that it won't be noisy due to the wear on the gears... I'd love to just get another one, but the longnose diffs can be a little tricky to find round here. I found one at a wreckers although he wanted $400 for it with no idea what condition it was in.... So I'm going to have a little bit more of look around to see if I can pick up a replacement pinion and ring gear, otherwise I'll just use the ones I've got and see how they go.


Also I've uploaded a bunch of other photos to a photobucket album, here is the link if anyone is interested.


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  • 4 months later...

It's been a long time since the last update, mainly because I've been away for work again... However I have been working on the Zed whenever I get a chance and there has been a bit happening lately. I've finished the exhaust which is now setup with the headers ceramic coated going into into a 3inch pipe, then stepping down to twin 2-1/2" to go into the cats. It merges into a single 2-1/2 after the cats, then through a resonator and a muffler. Here are a couple of pics.


If I had realised that the coating would show up the grinding marks I would have put some more work into getting them smooth... oh well, I guess you learn for next time.







I've got the clutch sorted, by using the AP racing master clyinder that I mentioned earlier. It bolts through the firewall (bulkhead style) with a nut on the inside to secure it. I had a clutch line made up that uses a short piece of tube bent as tightly as possible to ensure it misses the cylinder head and even though it is tight, it had enough clearance.




I've also had a custom drive shaft made which uses a 3" tube with heavy duty Spicer joints and I'm assured I won't be able to break it. For any guys in Sydney, I'd highly recommend Sydney Driveline who made it. They know their stuff and have good prices too.


I've had the OBX centre installed in the diff, along with new a new pinion and ring gear (3.7:1) and all new seals and bearings.


I've somehow managed to loose the pics of the rest of the exhaust, diff, driveshaft etc... although when I find what I did with them I'll post some up.


The best bit is now that I have done all of the above, the car actually moved backwards and forwards in the garage under its own power! I've just gotta get the brakes sorted and then it should finally be time to take it for the first drive... So hopefully another couple of weeks and I'll be able to post a video up.

Edited by Marc280
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  • 1 month later...
  • 4 weeks later...

Ed, it's good to know that there are people out there still following this considering how long it is all taking :) But I can confirm that the zed is now moving under it's own power and I have taken it for a quick lap around the block. I've also completed a front brake upgrade and made a aluminium fan shroud for two thermo fans amoung a bunch of other bits and pieces I've been tidying up.


Unfortunatley the car isn't registered and I've got to go through the whole lengthy engineering process that we have in NSW, so it may be a while before I can get any good videos. Although I will take a break from working on the car sometime soon, to post some more pics/vids up.

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  • 3 months later...

Ok I haven't been able to work on the car as much as I'd have liked since the last update as I've been away for work again, but I have managed to get the car a little closer to the rego/engineering stage.


Here is a list of all the things I've been up to, including: installing new (upgraded) front brakes, relocated the battery to the boot with a circuit breaker and cut off switch, built a fan shroud for the thermofans, built an airbox, relocated the radiator overflow bottle, sealed up the gearstick surround, bought and fitted Rota wheels, rolled the guards, made up a fuse/relay box for all the new relays and fuses under the bonnet and finally I'm not working on the instrument cluster to put a new Autometer speedo and tacho in.


For those that want to change their r180 diff to an r200, the following picutres may help a little. Here is the where you get access to the diff mount in the boot




This is the diff mount in the r180 position




With the mount removed you can see how the bolt can be in two positions with the slotted hole




Now with the bolt moved into the r200 position




And the mount put back on your done!




There are two different rubber mounts with one for the r180 and a different one for the r200. There are only slight differences between them and from memory they have a slightly different centreline and the two bolts that actually bolt to the diff are different sizes (the differences can be seen clearly in the factory manual). I bought this new mount directly from Nissan.




Here is a picture of the rebuilt diff in the car




And for those who don't really know how the OBX centres work, the following video may help a litle.




Ok that is probably enough about the diff. I had a 16inch thermofan on the raditor back when I was running the L28, however with no fan shroud and it just stuck to the radiator, I found it didn't really cut it on hot summer days. So to try to prevent any troubles this time I have gone with two 12 inch fans and actually built a 'proper' fan shroud.


I started out with an aluminium sheet, marked it up to suit the fans and then cut away.




with a lot of cutting, filing and welding later I had this (I think my next investment will be a plasma cutter as I'm sick of cutting everything with a hacksaw :) )




Then with the fans mounted




And a pic of some of the welds




Unfortunately they didn't all come out like this as I was a bit out of practice... oh well


and I just realised I haven't taken a shot specifically of the completed setup in the car, but you should be able to see this in some of the other pics.


Now for the airbox I've made up an aluminium enclosure, that seals in against the corner of the engine bay. I started out mocking it up out of carboard as shown below to make things easier.




Completed in cardboard




Made into aluminium




And complete!






I had already moved the battery to the boot, but I decided I really wanted to have a circuit breaker on the cable to the front as if this shorts for any reason it wouldn't be pretty. So I installed a circuit breaker on the positive side and a cut-off switch on the negative. I know this is probably overkill, but it also means I don't have to open the lid of the battery box to disconnect the battery now, which is handy when doing work on the car. The straps to hold down the battery box are two tie downs each with a breaking strain of 200kg, so I think they should be able to do the job.





Now for the brakes... I ended up going for a kit from 'hoppers stoppers' that is here in Australia. It uses 300mm discs and big twin piston calipers that is a similar setup used on local Falcons and Commodores. I'm hoping that if it can pull up these big cars (1700kg and up) then it should work well on the Zed. It was pretty much a bolt in job although the mounting point of the adaptor braket needed a little filing to be able to fit the caliper cage.


Here are the calipers after I painted them with high temp paint




A comparison of the discs




New hubs that mean you can use the newer hat on rotor style of rotors




Caliper cage on






Complete looking through the wheel




and a couple of views under the car






I didn't end up changin the master cylinder, however I'm planning to eventually mount a 'HQ' 1" master cylinder with a new double diaphragm brake booster. However, this will require a little stuffing around, so the stock master should do for now.


Ok, after installing the brakes I didn't plan on getting new wheels as I was told that the 16 inch wheels that I had (B45 Simmons) should have plenty of room to clear the brakes. But... after trying to fit the wheels after installing the new brakes the wheels didn't even come close to being able to clearing the calipers... Most 'newer' style 16's wouldn't have a problem, but seeing as these didn't fit and I wasn't going to go for smaller brakes, it was time for new wheels!! I'd been looking at a few other peoples 280zx's with the Rota RB's and I decided that this was the way I want to go.


Here are the wheels






For the wheels to fit required the guards to be rolled, like so..






And here is the Zed with the new wheels!









Ok so that is a pretty massive post, but hopefully for those that have been following that gives a bit of an idea where I am at. I'm currently modifiying the instrument cluster to be a able to fit an Autometer tacho and speedo, which is proving to be a bit of a challenge as I have to cut parts of the circuit board behind the cluster... I'll post up how I go soon. After this I have to fit a charcol canister for the emissions and then I can finally start the registration and engieering process!

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  • 6 months later...
  • 1 year later...

So I know it has been a while since the last update, but this is still moving along, but at the moment it feels like one step forward and two back....


It went it for the first 'engineering inspection' that is required for registration here and it came out with a list of things that they didn't like... these were


- Wheels not allowed as they consider them too wide and the offset change it too much (max allowed increase is 25mm in wheel track)

- Seats needed more padding around the head rest area (I've installed Cobra fixed back seats since the last update)

- Rear seats and belts need to be removed to register it as a two seater as the front seats don't recline

- Heat shields required on the engine pipes up to the catalytic converter

- Because the cats had to be moved back to the end of the gearbox to get them to fit, this is considered a big change to the emissions and therefore requires and emissions test (more on this later)

- Brake master cylinder must have 230ml capacity (this is to allow for any idiot to drive the car and fill it up with full pads and then never check it before the pads are worn out.....)

- Noise test required

- Overtaking test performed

- Speedo calibration report completed


So with this wonderful system that we have here I started working through the list.....


I decided to get another set of rota wheels becuase I love the look and I would eventually get a set for the track (but only planned to do this down the track). I got a set of Toyo semi slicks to go on them so these should be able to pass engineering as they are 8.5 inch and more importantly have a +4 offset.


Next I had the brand new seats pulled apart to have extra foam added to the head rest area ( I love it that these will pass FIA standards but aren't good enough for our local rego)


Now the big fun has come with emissions.... I went in for the IM240 test that they use to determine the emissions (I think this is pretty similar to what the guys in California have to go through) and it failed on the NOx levels being too high... I also had the problem that the car wouldn't start just before the test (perfect timing) and I traced it back to a dodgey relay, although in the process of finding out that the relay was the problem I blew the fuse from the alt to the battery (battery is in the boot) so it wasn't charging. So now I'm not sure if the low battery voltage was effecting the emissions or if it was always going to fail.


The site has changed since I last posted and I can't see how to attache the pdf files, but once I figure that out I'll post up scans of the results. Basically you can see from the first test that the cats being further back isn't helping as the emission are much better on the second run after they are hot.


I decided to install two new aftermarket (Magnaflow) cats so that I could get them up close to the engine. I've seen some people that have had good results with them in passing emissions, so hopefully they will work well for me too. After getting the cats installed I seem to have unleashed a whole lot of other problems....


When I first started the car after installing the cats the engine was hunting at idle from about 1000rpm to 2000rpm. I know that the Idle Speed Control Valves can be a bit of a problem with the idle, so I pulled it of to check it and there was a little bit of carbon buildup, but nothing that should stop it from working. While it was out I tested in on the bench by applying 12V to the pins B1 and B2 and then you can cycle around the four pins tapping it to earth to simulate what the computer does. It was all working ok and stepped in and out. I deliberately closed up the gap a little before putting it back in beacuse it was pretty much wide open when I took it out and I'm pretty sure that is what was causing the hunting idle. After reinstalling it the idle is now really low and it still isn't adjusting the idle up or down.


I checked that it is getting battery volts back at the ECU on the four ISC pins and that the computer has a good ground at E1, but the computer doesn't seem to be moving the stepper motor... In the factory manual it says that you should be able to hear it clicking when you turn the engine off and it isn't doing this either.... So at the moment I'm thinking the computer may be stuffed...


After manually adjusting the idle enough to get it to idle I took the car for a drive and now that I have a wideband I could check the mixtures. I found it was running really lean everywhere. At light throttle it was up around 1.7 lambda which obviously isn't good and probably a pretty good explanation for why it didn't do so well in the emissions... When trying to accelerate it was very hesitant until about 3500rpm and then accelerate ok , but still quite lean at about 1.3 lambda.


I tied pulling of the AFM and with it off the car didn't really want to start so I think it is working ok.


So sorry for the long ramble, but anyone who knows these engines can provide some insight that would be good. I do have a Haltech E11V2 sitting in the garage just waiting to go on but I wasn't planning on using it yet becuase the engine is pretty stock and I thought the stock computer would easily pass emissions... I'm starting to think I should just get a patch lead and have it tuned...


So if anyone is still following after reading all of that I'll try post back some more progress soon to let you know how it goes!

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If the ECU is going into diagnostic mode, then it *should* be good. However the early Toyota ECU's are known for dying from leaking caps. I would remove the ECU to inspect.


I know on the ISC, the one from the Soarer is prone to failure, as is the one from the Celisor/LS400. However the LS400 is rebuild-able, and the bearings are easily sourced.


On my SC400, I've had a bunch of bad luck with the ECU's.

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  • 2 weeks later...

Ok I think I've worked out what the issue is... Pulling codes from the ecu was a little tricky as the wires to the diagnostic plug are cut at the ecu, but I shorted Te1 to E1 at the ecu and then connected a test light to pin 6 of the 40 pin plug (the 'W' signal). When doing this to get the codes the light just stayed on. According to the lexls site this.indicates ecu problems which is what I was thinking maybe be the problem.


So I pulled the ecu apart and found that 7 of 9 of the larger 'can' type capacitors were leaking pretty badly. I've seen that this can be a common problem, so I really should have checked it earlier.



What do you know success! I replaced all of the caps (ended up ordering them from Mouser in the US) and now the idle speed control works perfectly and the AFR's seem much better! You can now actually watch the wideband display and see the feedback from the O2 sensors (I've got a Tech Edge wideband feeding back a simulated narrowband signal to the ECU) helping with the computer trimming the AFR's back to lambda 1 (14.7:1 AFR) at idle and on steady throttle. Under heavy and WOT acceleration it goes to about 0.8 (about 11.8:1 AFR) which is nice and rich like all factory Toyotas tend to do.


The caps I ended up using are the 'PJ' series Nichicon caps as these are supposed to be the replacement series for the old PF series. After doing some researching on-line it seems that leaking caps are a very common problem on many cars that are about this old. Apparently there are many other types/brands of caps that will work but I wanted to stay as close to the design that was there becuase the ECU seems very sensitive to these caps. From what I've read it seems the important thing is that they have low ESR (Equivalent Series Resistance) as from my understanding this means that they can handle higher ripple currents without overheating (that could be completely wrong though...). There is a list of caps with low ESR that should work here




And for a good overview of the Nichicon caps take a look here




There is a really good thread over on Club Lexus that runs through all of the issues with leaky caps in these ecu's. One of the guys posting even seems to be an engineer from Nippon Denso and knows his stuff.




So now I just need to get to the emissions testing station and this time I'm a little more confident/hopeful that it should pass. I have a test booked in for the 19th of December but that probably won't be enough time to get the test and finalised the engineering cert before christmas, so I'll be calling the RTA everyday to try to get an earlier appointment as I really want to be able to drive it over the Christmas and New Year break!


To anyone else out there with a 1UZ and running a stock computer, if you haven't checked your ECU for leaky capacitors I'd be doing it now! The engine is also so much more responsive down low now where before I was a little disappointed at how slow to respond it was.

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  • 3 months later...

It's been a while since I updated this thread again, but since the last update I found that the repaired computer only worked a couple of times before going back to it's old annoying tricks.  I figured that seeing as some of the caps had leaked quite badly there was a chance that the computer was damaged in some other way. So I ended up getting another computer and since replacing the computer all the problems described above went away.


I've also managed to get the car through the 'engineering' process that is required here so it is officially 100% legal to drive on the road and registered!


I bought a second hand GoPro and planned to take some videos of it driving/running, but it needs a new battery.... So videos will have to wait a while.


I've been driving it around a little and sorting out little issues here and there and now basically have the goal of tidying the car up generally and enjoying it for a while before I make any other changes.


Since I changed the gear oil in the diff to Penrite Sin 80 gear oil, all of the noises/clunks/bangs in the diff or gone.  So far I'm very happy with the diff and I've taken the car out in the rain a few times and it is very controllable when it breaks loose (which is very easy in the rain  :icon10: ).  I have a clutch type LSD in my other car (Falcon XR6 turbo) and the OBX centre seems to make it much more controllable than the way the diff in the XR6 behaves.


One issue that I'm still trying sort out is a vibration in the rear end.  It only occurs above 90km/h and only on deceleration.  Putting the clutch in doesn't change anything and as soon as you apply even a little throttle it goes away and is nice and smooth.  At first I thought I may have stuffed the driveline angles and after measuring them again I found that the gearbox did need to go up a little.  I put some washers under the bolts in the gearbox mount to move it up, but this didn't seem to change the vibration at all.  I've changed the tyres/wheels to another set and no change there either.  So at the moment I'm thinking it is either a mount, the CV axles or the driveshaft.  


Anyway hopefully I get that issue sorted and I'll post some vids soon.

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  • 2 weeks later...

Battery for the GoPro is here so I've taken the first video of it driving onto an onramp.  The video is only short, but should give you some idea of what it sounds like at least (the video doesn't really do it justice as it sounds much better in person...)




I've mostly sorted the vibration in the rear end.  I saw a trick somewhere that suggested putting two hose clamps on the tailshft and then moving the bolts around at different points to see if it changes the vibrations.  By doing this I was able to make the vibration better and worse, so it seemed like the tailshaft was the problem.  I took it out and went back to the shop that made it and sure enough it was out of balance.  The guy there reckoned that they u-joints sometime take a while to wear in and they often need balancing after the first little while.  I'm not sure how true this is or if he was just trying to hide his mistake, but at least the vibration is almost gone.  I say almost, because there is still a small vibration there at about 90km/h, but it seems to go away above this, so I think it must just be a resonance point and it is such a small vibration I can live with it for now.


While I had the tailshaft out I put a laser on the diff and one on the transmission flange and the alignment looks good. So I don't think the drive-line angles should be a problem.


The other thing I fixed was the side seals on the diff were leaking.  There was a whole lot of crud and git in the seals.  I don't know how this got in there, but the seals that the diff shop used also looked a bit different to the genuine Nissan ones that I bought to replace them, so maybe the seals just weren't the right ones.  Anyhow there are no more leaks from the diff now so that is good!


Also I had a couple of small leaks from the ehaust after I played around with the gearbox mount, so while everything was apart I chose to fit two flexible bellows in the engine pipes.  If anyone else is making an exhaust like this, I would highly recommend putting these in!  It made the whole assembly and construction of the exhaust sooo much easier.  Before if you were even a millimeter or two out you would have to rely on the bolts to pull of the exhaust flanges together and this was probably contributing to the leaks.


Anyway that is enough rambling.  I'm going to be at a motorkhana and drag racing day over the Easter holidays, so there should be more videos to come!

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