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Discussion Starter · #1 ·
I was just wondering what the differences between the JZA70 and the JZX90's were.

I will be doing the swap soon.

also things i just need to check is do all 1JZ-GTE manuals come with R154's or are there some manuals that come with the W5X's?

I have my car (JXZ90) arriving in a week so cant wait to put the not-so-naffed- engine in...

were other things... but cant rememebr at the moment :eek:

cheers...
 

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Impractical
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I have a JZX90 1JZ sitting in my garage, and a JZA70 unit in my mk3.

The primary difference lies in the sump, bolted onto the bottom of the block, onto which is attached the oil pan. The JZA70 engine has a "rear sump" to clear that car's front crossmember, and the JZX90 has a "front sump" for the same purpose in the Chaser. For a visual reference, go here:

http://www.1jz-gte.us/Images/1J sump differences.jpg

Most JZX90 engines also have an additional throttle butterfly just upstream of the main throttle plate, for the traction control system.

Also, the cast aluminum turbo outlet pipe on the passenger side of the engine, just before the ducting takes a downturn towards the IC, is more or less 90° to the centerline of the engine, whereas the JZA70's piping is routed at a shallower angle. This has to do with the piping differences through the front bodywork of the respective cars.

There are subtle wiring differences, like the electrical terminals for the injectors accept a slightly different plastic clip, but the JZA70 clips will work with a little effort. Most of the sensors are interchangeable, I believe, but the connectors to the ECU and in the ECU area are completely different.

To the best of my knowledge the motor mounts AND aluminum brackets are different.

The oil return piping is slightly changed as it goes under the passenger side bracket.

The dipstick and its pipe are located differently on account of the sump.

That's all I can remember off the top of my head. Corrections/additions welcome.

Matt
 

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Discussion Starter · #3 ·
Cheers for that.. was quite sure about all them pointers apart from the sump... some one mentioned... and thats not biggie...

heres a pic of the engine bay of the actual on im getting:




Do you know if the manual JZX90's comes with the R154 or not? im sure it would..

thanks again...
 

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Impractical
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Yes, they came with the R154, but with a different speedometer drive gear depending on the ratio of the rear end. But that's not a crucial difference.

Nice engine bay. Looks very clean... Good luck with the swap!
 

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OH SHIT!!! I'm in trouble! I just took a look at that diagram. I've NEVER seen the two compared side to side before. I've got a 1JZ from a JZX90! Am i screwed? Has anyone actually installed a 1JZ from a JZX90 into their MKIII??

I have a cut engine harness so i would assume that the wiring would be different between the two models. Correct me if i'm wrong.

I need help from anyone and everyone on this. A lot of you know about what's going on with my project and how long it has teken me to get everything together.

If anyone has info on ANYTHING pertaining to a JZX90 could you please send me that info by email, pics, web sites, Anything...

Thanks
 

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BigTSetter said:
OH SHIT!!! I'm in trouble! I just took a look at that diagram. I've NEVER seen the two compared side to side before. I've got a 1JZ from a JZX90! Am i screwed? Has anyone actually installed a 1JZ from a JZX90 into their MKIII??

I have a cut engine harness so i would assume that the wiring would be different between the two models. Correct me if i'm wrong.

I need help from anyone and everyone on this. A lot of you know about what's going on with my project and how long it has teken me to get everything together.

If anyone has info on ANYTHING pertaining to a JZX90 could you please send me that info by email, pics, web sites, Anything...

Thanks
No one that I know of has installed a straight JZX90 1JZ in a mk3 because it simply doesn't fit with the front sump. That's right where the front crossmember is located in the Supra. The good news is that the bits that you need to convert it to rear sump can be sourced from a 2JZ as well. You'll need an oil pan, sump, oil pickup, and baffle, along with a few other bits I believe.

The wiring is essentially similar except for a few minor details like injector clips and ECU connectors, so you could likely reuse the bulk of it if you're handy with a soldering iron. The JZX90 MAP sensor is different, though--at least they're two different part numbers. I'm not sure whether the voltage readings are different between the JZA70 and JZX90 units.

Other than that... The two powerplants are identical save the stuff I mentioned further up in this thread.

Matt
 

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Okay, so here it was i have for my parts list.
1JZ Access Rom tunned with 550's.
1JZ wiring harness that plugs directly into the Rom.
A Cut harness on the engine as of right now.

The Access Rom SHOULD work with the JZX90 right? They are still the same engine and since i'm making pretty much my own wiring harness from the 1JZ harness that i already have i SHOULD be okay.

I will check into changing over the oil system. I might just be able to change the front pan, lines, pickup and sump. I'm sure that i can get those parts pretty easy.

What else? THoughts, comments Anything from Anyone would be helpful.
 

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BigTSetter said:
Okay, so here it was i have for my parts list.
1JZ Access Rom tunned with 550's.
1JZ wiring harness that plugs directly into the Rom.
A Cut harness on the engine as of right now.

The Access Rom SHOULD work with the JZX90 right? They are still the same engine and since i'm making pretty much my own wiring harness from the 1JZ harness that i already have i SHOULD be okay.

I will check into changing over the oil system. I might just be able to change the front pan, lines, pickup and sump. I'm sure that i can get those parts pretty easy.

What else? THoughts, comments Anything from Anyone would be helpful.
If you ever do this swap, tell us how it goes. :p

JZX90 MKIII Supra....hehe, it would be pretty cool.:D
 

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Well, it might just HAVE to happen!
 

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Discussion Starter · #12 ·
oooooooooooo-kay!

what a mission...

I have managed to drive my JZA70 tonight with the better SMOKE-FREE engine :D with the help of some mates of course...

Well i noticed tooooo many differences from the JZX90 and the JZA70 1JZ's..

Heres the list:

a) Mounts - on the 1JZ bloch you will notice 6 bolt holes,top 3 run parallel with bottom 3 kinda like this : : : -the JZX90 mounts are the 4 more forward holes and the JZA70 are the 4 more rear holes.

b) Alternator - this had a more modern plug, may have been the 2 years difference... not too sure...

c) Starter - This again had more modern plugs so couldnt use the starter.

d) Airconditioning Compressor - Alot different from the compressor.. but might have fitted usung piping that bolts to chassis mounts

e) Sump - Obviously this being a front sumped engine, it had to be changed over... i think the most time consuming part of it all :eek:

f) Front Pipe - (down pipe) curved differently, i guess to avoid different parts in the engine bay due to a different mounting position...

g) Gearbox (R154) - the shifter from the JZX90 has a cradle similar to the V160 (MKIV 6 Speed)

h) Front Shaft - NJo biggie but mounting holes are closer to gether... wanted to use it as it has the newer hanger bearing.


Ok - thats all i can think of for now... if i rememebr something io might just add it to the list ;)

hope this helps...
 

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So...? Were you able to get the motor in and running? Or did you give up b/c it was Too different?

What does it take to put this motor in Besides the new oil pan and all other related oil stuff? Do i need to get different engine brackets?

B) Did you use a different alternator?
C) Did you use a different Starter?

I was already planning on building custom AC lines so that's not really a big deal.

Thanks for all your help
 

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Discussion Starter · #14 ·
yip in and runnign sweet...

should have added i used the Loom and intake manifold from the older one along with the TB as the JZX90 has traction control (a 2nd butterfly which is normally open but closes when ABS computer tells it to)

I used the JZA70 loom and all acessories with it... so at home all i have left is a 92 JZ long block with all the bits to put back into the JZX90... if you know what i mean...
 

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So in order to get this to work i pretty much need a different engine! Either that or go stand alone. SHIT!
 
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