280zx 2+2 RB conversion

[niroshann]

I thought of starting a thread to document a bit about my RB conversion journey to-date. Ill go through what I have done in the past and make updates. Hopefully the info may be of interest or may help someone. Note that I am not a perfectionist so my work so far has been to get the car driving. I would love to get a full body restoration etc done sometime after driving the car for a few years (hopefully).

I have owned ZXs since 2004 and was on my third one when I moved to the UK through work in 2008. I sold the car prior to leaving and missed it too much so ended up buying another one in New Zealand in 2010 while I was still working in the UK - I used to travel back twice a year so loved driving the car when I was there. Plan was to move back to NZ.

The car was a nice 280zx 2+2 targa and thought that I would do an RB conversion on it when I was back in NZ. I had seen too many projects end up stalled and decent cars off the road for years so decided to trial fit everything on a donor shell and when ready, transplant the lot into my good car. As the story goes, I moved to the UK and brought the lot over and the donor car was worth keeping so now I have two 280zx cars. I love the old L28 as well so this is a great way to keep one car original and mess about with the other one!

I did do some of the work during my holidays in NZ so this is an international project! Photos show the donor car when I picked it up (I also got another ZX (1978) with it and a tonne of parts but had to sell it all off before bringing just the two cars over - wish I had kept the lot). A ZX pulling another ZX on a trailer would not work in the UK, but in NZ I didn't have trouble hiring the braked trailer and moving the car! The auto box had to work hard and I recall seeing the temp gauge rise above normal. I employed a usual trick to cool the car down (as I have done in the past with earlier ZXs) - just pop the bonnet plus turn the heater on!

 

[SeanDezart]

True - not enough swap-jobs on ZXs. At one point I fancied a LS1 in one. Keep us posted.

 

[Rob Gaskin]

Yes an interesting change to the S30 conversions.

Seen this:

https://www.ebay.co.uk/itm/Datsun-2...301168?hash=item239c30d470:g:6PQAAOSwhktaqLdu

 

[niroshann]

While in the UK, I had remotely purchased an RB25DET NEO engine for the car and also sent a manual r34 gearbox from the UK to NZ! The box was considerably cheaper in the UK at the time than sourcing in NZ! This drivetrain is very sought after there and so prices were very high - gearbox as much as engine in some cases.

Then during my holiday in NZ, on the same day as picking up the template/donor car I picked up the engine from storage using a smaller trailer and had everything in the garage. Parents were not too impressed!

Reversing the trailer with car on it up the drive was a challenge but having an auto box did help! The gold ZX did well that day! At the time I was looking to replace its drivetrain completely so felt a bit sad that it worked so hard without question - if it only knew what was coming!

 

[niroshann]

Yes an interesting change to the S30 conversions.

Seen this:

https://www.ebay.co.uk/itm/Datsun-2...301168?hash=item239c30d470:g:6PQAAOSwhktaqLdu

That V8 looks nice and it’s also a 2 seater. Must be a fast car!

 

[niroshann]

True - not enough swap-jobs on ZXs. At one point I fancied a LS1 in one. Keep us posted.

LS1 would be a nice setup! They do swap in Chev small blocks or V8 ford Cleveland and Windsors in to these in NZ. Have seen a few turn up for sale. Yet to see one in the flesh!

 

[SeanDezart]

Ford is a four letter word.

Yes Rob - seen it although it needs new paint and I'd want to thoroughly check out the bodywork : "no dangerous rust, body good no dangerous rust,
but paintwork has some spots that need attention ,mainly bonnet/rear hatch".

I winder what the history was - it being a RHD 2x seater targa - I don't think it's a European version.

So overall, an expensive car but quicker than DIY.

 

[niroshann]

Ford is a four letter word.

Yes Rob - seen it although it needs new paint and I'd want to thoroughly check out the bodywork : "no dangerous rust, body good no dangerous rust,
but paintwork has some spots that need attention ,mainly bonnet/rear hatch".

I winder what the history was - it being a RHD 2x seater targa - I don't think it's a European version.

So overall, an expensive car but quicker than DIY.

Never seen a 2 str targa in NZ. Could be Australian or from a RHD African market? Wonder what bodywork is under the body kit.

 

[SeanDezart]

Wonder what bodywork is under the body kit.

My thoughts !
Maybe a JDM car ?

 

[Ped]

Hi Niro, great that you are starting a thread on this. I have seen the work in progress on this car first hand and it looks very interesting, I can't wait to see it on the road. What I never really appreciated on a conversion like this is the amount of wiring involved, fully respect!

 

[Huw]

ZX pulling a ZX not something you see every day. Looking forward to seeing this progress Niro. Good to see a ZX conversion for a change. What made you decide to do it? Gold and black car looks very clean btw.

 

[niroshann]

Hi Niro, great that you are starting a thread on this. I have seen the work in progress on this car first hand and it looks very interesting, I can't wait to see it on the road. What I never really appreciated on a conversion like this is the amount of wiring involved, fully respect!

Thanks for the encouragement Peter. Was good seeing your lovely ZX and catching up with you. The wiring has been a challenge indeed. It continues to be a challenge with wiring up gauges etc. Fortunately the ZX is simple in its wiring so I have been able to piggyback on it easily!

 

[niroshann]

ZX pulling a ZX not something you see every day. Looking forward to seeing this progress Niro. Good to see a ZX conversion for a change. What made you decide to do it? Gold and black car looks very clean btw.

Cheers Huw. Gold one is a bit neglected now sitting covered in garage, but is a problem free car that I drive in summer. I converted it to manual sometime after the photos. I've always been into the 280zx (i suspect due to a childhood toy). I wanted to get a bit more power and in NZ the L28ET setup cannot be found. Given the efficiencies with the new engine and availability I opted for this. Other contenders were the VG30DET or the SR20DET engines. I preferred the same format (straight 6). Don't plan on increasing boost or upgrading engine as my goal was to have a stock skyline engine setup - more than enough for me.

 

[niroshann]

Still back in 2010/2011 and I've got the car and the engine home to work on. I had purchased the RB25DET NEO in NZ while I was in the UK so had not seen it in person. It was a low mileage engine (around 50k miles) and the previous owner had not been able to get it running with his R32 skyline. I was hoping that it was not messed up or damaged but it was a good deal so I took a chance.

The engine as I purchased it. Came with the full loom also. It was from an automatic car. The turbo seemed to be okay - very slight lateral movement in turbine shaft.


The passenger side engine mount bracket was missing and so I went about finding one that would suit the engine and the ZX front subframe. I had to visit the wreckers yard (like u-pull-it in the UK) to compare the engine mounting brackets. I found that none of the engine mounts between R31, R33 and R34 skylines were exactly the same (there were no R32 skylines to reference from). Of the ones I found, I thought that the R33 ones looked like a good match and so I purchased two of these brackets.

Passenger side engine mount comparison. R31 on left and R33 on right.


Driver's side engine mount comparison. R33 on left, R34 on right. Obvious differences to tackle later.


The reason why I had to go looking for brackets was because the R31 Skyline brackets and mounts I got (assuming they would be closest to the ZX's subframe would not match the bolt pattern on the much later RB engine.


Comparing the actual engine mounts (ZX on left, RB on right), the job looked a bit easier as they look close to the ZX ones. I recall these RB mounts being from the R31 skyline parts I got although I believe the R32/R33/R34 skylines have the same format.






The only change needed was to drill a locating hole on the ZX subframe.


A precision job!

 

[niroshann]

Been a while since my last post. Busy times with family etc. I did do some more work on the datsun, and ill put those details up later. In the meanwhile, thought that I should continue the story a bit more.

Using the R33 engine brackets and the RB engine mounts, I went about installing the engine into the project car.



Part-way through the install I found that the sump needed to come off. Should have spotted this before, but I was rushing as the engine lift was on rent and due back soon.

Engine was finally in



The way the engine sat on its mounts was far from ideal as the rubber idolaters were too far apart in relation to the mounting brackets on the engine and left a gap as the photo shows.

Left engine mount (as you look into engine bay)

Right engine mount - note gap


This was putting a lot of stress on the rubber mounts and would lead to problems later on. As I saw it I had two options

1) Drill new holes on the engine cross member to move the rubber isolaters lower.
2) Try and add spacers to engine mounting brackets

I went for the latter as it was less intrusive and gave me the opportunity to adjust things if I got it wrong. These were the spacers that I chose. They came from an exhaust manifold of a Nissan Skyline. I had two sizes in case the corrections achieved was too much. I ended up using the larger 5mm washers on both engine mounts (between metal bracket and engine block). I had to get longer bolts as 5mm of thread was effectively lost.


Left and right engine mounts after spacers were added




Looking at how the engine sits vs the stock L28 in my other car. Using this setup, it appeared that the engine sits forward, but at the same time, there is not much space between the back of the engine and firewall so I think this was a decent position using minimal fabrication.





I have since seen seen a 280zx RB25DET Swap Mount Kit available from Fever Racing. The photo below is from a facebook group called "280zx Club" and the person who posted was
John McBride. He has put up a few photos showing how this goes together.




Out of interest these were some of the donor cars. The white Skyline was a very useful find!


Poor old Datsuns (NZ assembled)


Loved visiting this place!

 

[niroshann]

Next was sorting out the oil sump pan, pickup and dip stick location.

The sump bowl in the RB engine is at the rear whereas in the 280ZX it is in the front. There is a sump pan from a Z31 shape, 200zx that would have been ideal as it uses an RB20DET setup with the sump bowl at the rear but it is a very very rare car. I sourced a sump pan from a Nissan Patrol that had an RB30 petrol engine with the bowl at the rear. This can be seen on the right in the first photo and then on the left in the second. Bolt patterns are the same across the RB engines which was convenient.





While the sump bowl is on the rear, it is obviously very deep so needs modification. The photo below shows the sump pan installed on the engine



It also came in contact with the steering linkage in my car. Car had the non rack and pinion style.


After a short stay at a fabrication shop, the modified Nissan Patrol sump was ready for installation. Because the Nissan Patrol sump is not too common, I had also considered cutting the skyline sump's base off along the length, rotating it 180 degrees and getting it welded back up but the fabricator told me that this may end up warping the sump.

Photos of the modified Nissan Patrol sump are below. Note at this stage I had already installed the gearbox. If I were to do this again I would do all the engine work prior to installing the gearbox as I wasted a lot of time trying to take the box off to install this sump pan - the steering linkage just wouldn't come off to give me the clearance otherwise.







They also cut, rotated and welded up the oil pickup to suit. No photos of it unfortunately. The relocation of the dip stick to the rear was really easy because the block has two access points that can be easily plugged/unplugged. The dip stick is a slight press fit.



Hole in front was plugged up using a bolt and a seal.

 

[niroshann]

I started this thread thinking that I would make a whole lot of updates but this obviously wasn’t the case.

Rather than leave it incomplete and since I am working on it now AND since we are bit thin on 280zx content, I’ll fast forward to today with some updates in case it is of interest to some.

I have had enjoyed the RB25DET conversion for a couple of summers in the blue car and have moved it to my gold and black 280zx as of the end of Aug 2020. The blue one is now running the stock drivetrain from the gold and black car and while it runs superb, I really miss the RB25DET!!

 

[niroshann]

I bit the bullet and decided to unravel the entire skyline engine wiring harness and strip out the redundant wiring. It was worth it as I ended up with about half of the wiring as I started out with and more importantly the car starts - not yet road tested with the “low fat” wiring harness yet!!

basically that container in the pic filled up with redundant wires. I was keeping the ZX wiring in place except for the L28 engine ECU harness and was simply replacing with the skyline engine harness with some extras included like Aircon compressor wiring.

 

[niroshann]

Once the harness was cleaned up, I then proceeded to install it into the car. Stuff of nightmares! Trying to work on this stuff with the car in a narrow garage and with limited access was a mission but progress was made each evening.

the bin of spare wires was kept in the car in case I had taken something off which I shouldn’t have!

I also learned that I had missed a wire in the original setup in the other car - neutral position switch gets wired into the ECU and it covers some functions that may lead to more power and changes in the idle speed! It felt powerful enough In the blue car but let’s see if it makes a notable difference now that I am using it.

the 280zx has a very handy plug on the ECU side with an ignition and a start signal. That saved me a bit of hassle!

 

[Ped]

Looking good, epic wiring though!