Here we go again, now a L700

Hello everyone, so long absent … the truth was a difficult year that little and nothing was carried out of my projects that i had in mind. Normally, as happens in difficult years, people take shelter in family or work and leave other things aside. I’m not the exception.

Although this damn pandemic has not happened completely, I think for mental health that it was time to do something … and well I present to me “something”.

I had already shown my intentions to change the little Sirion for an L7, in fact I bought one at the end of 2019 but I found this one and decided to make the change.

Here in Chile there are very few 3-door Miras and although the car is not in such good condition, it is not so bad for a 20-year-old car. (except the engine that looked like a fireplace)

The intention of this car is to replace the little Sirion but taking advantage of everything he learned from him and everything we fix or worsen depending on the point of view.

Basically it will be the typical change from ej to k3 but, a point, I need the car to be able to circulate moderately through the city, that means that it cannot be a full track car, so in many ways it will be an everyday car, even if isn’ t “my car” for daily use.

I just started with this project, the car was acquired on 12/29 and I started with it on 01/01, I don’t have much progress but at least I have some photos.

I hope to have progress between now and the next weekend, I want to have the engine mounted at the end of January.

A big bear hug to all


I loved your first build! I cant wait to see more of this one. :slight_smile:

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Fantastic. On seeing left-hand drive it gives me a little head spin and rechecks of what I am looking at.

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Hi everyone!

I don’t have much progress, actually, rather, many questions.

Well the first, I cleaned the whole interior, wash the carpet, changed the steering column, wash the Sirion seats (they fit perfectly) and put the sirion steering wheel

Another thing that I started to do was the dissarm of the sirion (it’s a mix between sadnes and anxiety) but it seems that the pandemic made it bad, the engine sounds strange so I think I am going to disarm it to review…

Now I only have questions
1.- Can the steering of mira be placed with sirion terminals? (Mira is mechanical and I prefer it over the hydraulic)
2.- If I place the sirion suspension arm, the car gain negative camber, everything works fine or should I correct something else?
3.- regarding the rear brakes, the axle is not compatible, right? I saw that it is better to change the brakes for the Sirion, I think I will go here initially (I bought the applause discs but I don’t think I will make the change for now)
4.- I will put the spoiler of the sirion … it seems to fit, has someone done it?
5.- This is more of a request … someone will have for sale a pair of cheap headlight for sale? I had to ask. :upside_down_face:

A big bear hug to all


Loving the start of this project thread…

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  1. Change the whole rack, they are both nearly 4 turns lock to lock here. I used Toyota’s ae86 (short pinion) or aw11 (long pinion) for 2.5 turns lock to lock. Steering will be faster. Watch pivot of rack ends up the same to reduce bump steer. You will need to swap method of attaching to the K frame and the splines to the steering column need a hybrid universal.

  2. You will gain too much neg camber. Adjustable tops should be enough.

  3. Put the Sirion rear wheel cylinders in they are bigger bore and will give more rear brake.

  4. Sure

  5. anyone got some?


the second point is the one that interests me the most of all. What does mean too much neg camber? -5° o more? I have Adjustable tops, but I don’t know if it can correct enough… To be honest I want to take advantage of the suspension, bushings and others suspension parts of the little sirion


-5 deg is prob as much as you’ll ever need. With the longer arms you’ll need to longer drive shafts. If the cradle is not the same length then you’ll need custom shafts. I’d prefer to gain more neg camber with slotting the top strut to knuckle holes on the strut lower bracket.

the sirion rack is too long.
same with the lower arms
better to use mira versions for proper suspension alignment
if you want stronger then get dsport spherical bearings and uprated bushings makes a massive difference
sirion shocks are too long - frankly the mira ones are too. if you can get copen ones cheap enough then good. otherwise better to get after market ones or stick with mira and short springs
steering rack is best mira. better to use a quickener than stuff around with other racks. is a lot of work and often suggested by people who havent tried to do it themselves and count the hours taken to get out there
most important is that you get it finished and start burning some fuel!

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Steering rack swap is indeed a big task. I have done this and by the time I figured out Toyota AE86 or AW11 (allows steering wheel moved rearward 25-30mm as it is the same as AE86 but has a longer pinion) was the best fit the cost had got out of hand. The cradle (K frame) rack mounts have to be removed and either new ones made or Toyota ones fitted (passenger side is easily fabricated). To use the Mira steering column a splined hybrid steering universals needs to be made from the union of a Toyota end, Dai end and the universal from either. Adding a Quiafe quick rack and pinion to the interals bought the turns lock to lock to 1.5 with a bit more steering angle to boot. The rack ends need to be spaced out a bit also to reduce bump steer (female rack end socket, female tie rod socket [both the same thread dia and pitch] and bridge the two with a high quality thread that enagages at least two and half times diameter, and a spacer goes bewteen the two). Essentially, the rod end centre should be be the same distance appart as the distance between the control arms pivots. The steering quickner is a much easier solution if legal or not worried about what is legal. Definitely go the less stuffing around route and be out burning fuel rather than working on the car.

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She lives again! (yes, is She)

The truth is we finished the assembly but she is already disarmed again, although she only walked one day I can say that it works and I love how she moves on the highway


P.d: Beautiful Monster by Ne-Yo is her song.


Awesome work mate! Looking forward to seeing how this progresses.

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Hi guys!

In the previous post I just wanted to tell that the change was in progress, although the engine was not as healthy as I wanted, at least I know that everything works. :slightly_smiling_face:

Finally after all that I have been thinking about I got a 3sz that needs repair. While I wait for the grinding shop, I have some comparative photos. It’s something that I would have liked to find somewhere before doing it on my own. If it helps someone, I’m happy.

First a photo of the little engine (or what was left of it)

First comment that it is different from what I had thought. It is basically a k3 with the longest block. In my celica 77 I had done something similar (1.6 to 1.8) by changing the crankshaft where the stroke of the crank changed from 70 to 77 mm using the same block, but the 3sz is a longer block with longer rods.

Well, let’s go with the photos. The block apart from being longer, has oil sprinklers towards the pistons (my k3 does not have them), the mounting points are the same as in the old block.

Crankshaft: I thought they could be the same and that only the length of the rods would change, but they look different. They use the same main bearing. The connecting rod bearing are different.

Cylinder Heads: Look structurally the same. The intake ducts are obviously larger on the 3SZ. (My cylinder head is ported and it’s also 2mm smaller). The exhaust ducts look the same. Intake valves are bigger, the exhaust valves could be a little bit bigger or not, my eye is not that expert … The last difference I found is that the spark plugs are 16mm on the k3 and 14mm on the 3sz.

Cams: Very very different intake cams (my k3 is a k3-ve2), exhaust cams could have a little difference. To my eye they looked the same, but in the photos they look different.

Oil pump: they are different …

Rods: They are longer, look a bit thin (I was surprised by that). They use different bearing. The 3sz ones are a little bigger.

The piston of the 3sz could be used in a turbo application, I was surprised how concave it is.

trigger wheel: they are different, you would have to exchange them if you want to use k3 electronics.

Well, as you can guess, I’m going to use the 3sz block with its cilinder head, but I will use k3 cams and k3ve2 pistons (I had the old ones from sirion stored). I don’t dare use the high compression pistons.

Finally, for the intake I’m preparing a four throttle since the engine I bought came without the intake manifold. (is of Yahama R1).

I hope it helps someone and sorry for the post so handmade, without using professional measuring tools.

Bear hug!


Amazing post mate! Really good to see all the differences laid out. Thank you for doing this.


those pistons almost look like my K3VE pistons :open_mouth:

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Awesome info dude my 3sz arrived from Japan today it only has 37,000 klms so I’m not going to crack it open , just some extractors and some cold air.


Dude this is awesome! So cool to finally see the differences between the engines. I’ve thought about it a lot, but in the end it’s best to just take everything apart. I’m going to throw in a 3SZ in my L7 this summer, so I’ll be keeping an eye on your topic to see how you’re doing! :smiley:
Good luck!


It’s been a long time and I think it’s time to stop being irresponsible and update this thread.

Well, first of all, let me tell you that the car is already operational and is running very very well. This is it current look.

I still need the paint fixes, I hope to be able to do them in the next few months, however, I have already done several of the things I wanted to do, for example:

Sirion spoiler

Sun-visor with mirrors (indispensable for my wife), sunglasses holder

Front sirion seats, rear upholstered with sirion fabric.

Chrome exterior handles

CX version clock

I really love how it looks inside (in the photo can see my Toyota Zelas, nice car :wink:)

Now regarding the mechanical items it’s basically a transplant from the Sirion, however, the most notable is the following:

Copen D-Sport SwayBar

Copen brakes with Nibk pads, Sirion brakes were placed at the back.

Front Cusco Coilovers adapted from Honda FIT

Intake and exhaust manifold

Now the fun part, the engine is a 3SZ as you already know, it has pistons and cams from k3ve2, injectors from k3VET, intake and exhaust. The rest is stock.
On the gearbox side, only the final ratio has been changed to 4.9.

With all these changes the result is as follows:

The truth is that the car run, turns and brakes very very well, especially up to fourth gear, fifth gear already feels short or the car is very square.

I’m really in love with the car and I hope to continue improving it, I would like a front bumper from TR but it looks difficult, for example.

Well guys, that’s the update of the car, now I have to take it to a trackday to be able to compare it with the sirion and see how it behaves on the track.



Oh man I’ve been dying to hear about your project for so long! So cool to see it all came together so well, and those power figures are truly astonishing. Naturally, I have a few questions :slight_smile:

  • How much torque (Nm on the crank) does it make?
  • Do the K3 pistons increase the compression ratio (and if so, by a lot?)
  • Are you running a standalone ECU?
  • How is the gearbox holding up?

Also, what do you mean by ‘difficult’, about the TR bumper? If you’re worried about fitment issues: the TR bumper fits better than a prefacelift bumper on my 3SZ L7, so nothing to worry about :slight_smile:

I’m looking forward to see more of your progress on the car!

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Hi bro!

I don’t know very well how a dyno calculates the torque but it makes 135 NM at 4750 RPM (It’s less than what Dai specifies (141 NM at 4400RPM). I think a good point of comparison is my previous k3ve2, in the same dyno it marked 105 NM at 5500 RPM, that’s a 30 NM increase on the same dyno (at least it’s more than a stock k3ve2 to a Stock 3SZ (21NM))

Regarding the pistons, the first attempt was with 12.5 CR Malaysian pistons, but the engine broke the gasket more than one time . Finally i buyed k3ve2 pistons, at least it doesn’t break and doesn’t detonate with the horrifying fuel from Chile, of course I can only use 97 octane (the best around here :pensive: )
If I can tell you that the advance of the engine is notoriously less, in the k3 it could reach advances of 39° (with highcom pistons), today the best I achieve is 30° (it also affects the length of the rods)

About the ECU, I’m using a speeduino, I love it, it’s like building an ECU with match sticks :slightly_smiling_face:
I don’t know if I understood your question about the gearbox correctly, how is it mount with the engine? use the sirion box, which is plug and play, or was the question another?

I see that my comment about the TR bumper was not understood either, TR did not arrive on this side of the world, I was referring to how difficult it can be to get one on these sides.

Thanks for taking the time to read!!