UPDATE: A limited supply of the original best-selling Lextreme 1UZFE EGR Delete Kit remains. If you own a 1UZ from 1990-1997, you really need to get this kit! Email me at [email protected] for help with ordering or questions. This will probably be the last kits I have made.

All other parts are SOLD OUT and won't return, including the LS400 and SC400 turbo kit, rebuild kits, supercharger and performace torque converter. We're not an auto parts supplier and I can't respond to inquries for random Lexus and Toyota auto parts.

LEXTREME LEXUS FORUMS HERE! - Post Questions For Quick Answers!

1UZ vs 3UZ

This is Part 3 of this 1UZ-FE Vs. 3UZ-FE write up.

The examination of the two engines was very interesting and extremely enriching.  I learn a lot from this experiment.

I think this engine comparison articles break down many mysteries we had about the legendary 1UZFE and the improved version of the original.  I did not weight the two blocks, but I would say they must be very close.  I do not think weight is a factor between the two blocks.  The picture below is late model GS430 block.  From the look of it, its very clean and minimum wear if any.

Here is closer look at the 3UZ all aluminum block.  You will noticed this block is very clean.

Something is very interesting I found out when I take out my measurement caliper.  The blocks are identically the same.

However, you will noticed the sleeves size are different.

The Inter-Sleeve Space (ISS) is what I call it.  This is the space between to sleeves.  In the 3UZ the Inter-Sleeve
Space is .574″ and the sleeve thickness is .187″

Here is my dead 1UZ block I have at home.  Even its dead block I still keep it around for mock fit parts and something like this.
Comparing engine blocks.  This block lived in my carport and get rain on and my lawn sprinkler system.
Therefore, you will see lots of rust and cosmetically unattractiveness.

Even its beat up and its ugly, but it still serve the purpose. Here is a closer look at the 1UZ sleeve.  Noticed any thing different from the 3UZ?

Now you can start to noticed the ISS in the 1UZ is much larger.
The ISS is much larger in the 1UZ.

Here is a picture for referrence on the 3UZFE.  Once again
the ISS for the 3UZ is .574″

The ISS for the 1UZ is .719″.  The ruler above and below is
just a reference.  However, I used a caliper for all the measurements.

Below picture is very interesting.  I put 1UZ heads into the
3UZ block.  Its a direct bolt on.

The above and below pictures are the first of it kind.  This combo is possible with minor modification on the 3UZ pistons. The sleeve inner diameter for the 3UZ is 3.579″ and the inner diameter for the 1UZ is 3.433″.  The sleeve thickness between the two engine is the same .187″.

Here is a side view of this combo.  So, what do we learn from
this experiment?

1UZ Vs. 3UZ Block 1UZFE 3UZFE
Sleeve Thickness .187″ .187″
Inter-Sleeve Space (ISS) .719″ .574″
Sleeve Bore Size 3.433″ 3.579″
Sleeve Thickness/Bore Size Ratio .0544 .0522

We I learned is that the 1UZ and 3UZ have the same aluminum block except the sleeves.  The 3UZ has a larger sleeve than the 1UZ.  However, the thickness of the sleeves for both engines are the same.  Due larger sleeves, the 3UZ have small ISS.  Now the question is having small ISS weaken the block?  ISS means less support for the sleeves and this is very essential during high hp application.

On the other hand, I wonder how would the 1UZ perform with 3UZ heads?  I think that is the optimal combination.  Even though its only .3 liter smaller but it has stronger block, stronger rods and beefier pistons.  If we can get 3UZ heads, then the flow would be much better.  Since the engine parts and interchangeable, therefore the mix and match combination would be endless.

What do you think?  Wanna input your opinion?  You can post it here.

Now the question would be which motor is stronger even they have the same sleeve thickness.  The Sleeve Thickness/Bore size ratio is .0544  for the 1UZFE and .0522 for the 3UZFE. Therefore the 1UZ has greater ratio for the given bore size. Another word the 1UZ has more sleeve ratio then the 3UZFE.

Note: ISS is the distant between two sleeves. Edge to edge.  1UZ have large ISS and therefore more

Other articles of interest:
Lexus 3UZFE rod vs. Lexus 1UZFE rod
GS430 Piston Vs. LS400 Piston (3UZ vs.

1UZ Vs. 3UZ Main Fasteners

Do you have any questions? If so, please head over to the forums to get a quick answer or share your experience!

Cash App (user: $lextremeparts).
This is a freelance site with no support by huge companies.  I have been doing most of the R&D and technical write-ups by myself with my personal money and literally thousands of hours of my time.  I have taken extra steps to demonstrate in details how things are done.  Currently I am one of the few people doing Lexus V8 research and performance enhancement.  This effort comes from my personal love for this wonderful engine.  Most of the modifications are from trial and error. There's no cookbook for 1UZFE mods and its unknown territory for much of supercharger performance.  The parts, labor, web development and site hosting are 100% paid from my personal hobby money.  If you feel my efforts help you in any form, please do not hesitate to donate any amount of money to support this site. You have no idea how much I and the entire Lexus and Toyota community appreciate it!

4 thoughts on “1UZ vs 3UZ”

  1. I learned a lot from your site, I installed the 1uzfe in a 91 toyota pu and now have 33 k now. I need info on the 3uzfe, computer hook up(key) mainly not sure what else is needed electrically . Is there a computer made to eliminate key theft deterrent?

  2. Can 3uzfe pistons be used in a 1uzfe.
    I’ve been contemplating a build. I currently drive a 430ls it’s fun and reliable but I want mo powa and I believe these engines have potential.
    I want to get a non vvti 1uz and build it with as much 3uz parts as possible and a run boost. The non vvti appeals to me more because it’s not an interference engine and it’s one less thing I have to worry about realistically I want 500 HP so I’d also be hunting a different transmission as well. Also is the 2uzfe block the same as the other 2 cast is heavier but also more durable.

  3. Many thanks for such great website!
    I’m currently considering a swap for my 1979 fj43, the option is 3uz engine mated to landcruiser manual.
    Should I reconsider the 1uz instead?
    Thanks again


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