Couple a Qs. (2UZ physical dimensions, rod/stroke ratio)

[jacob]

Hello people and Lex,

First, I must say you and your dedicated members have really created quite an awesome forum and site. The site and the tech articles have been sooo helpful. It has saved me a lot of searching and unnecessary posting. I am glad too see so many contributing members; these type of guys are what decideds the greatness of a forum.

I do have a couple of questions. I am sure Lex can help me out with this one, since he has been working with the 2UZ lately. If the piston of the 2uz exceeds the deck height, could I assume that the 2uz heads would be taller than a 1-3uz's heads making the physical width of the engine broader. If it is wider, by how much.

Second Q is about rod/stroke ratio. I used figures from the tech pages. The 1UZ's rod length (center-to-center) is 5.744 and stroke is 3.25 (3.3 for the 2UZ). From what I remember rod length divided by stroke gives the rod/stroke ratio. The the ratio for the 1UZ is 1.76 and the 2UZ is 1.73. Is this correct? I am not sure if I should be using the center-to-center rod length. A Honda B16's ratio is 1.74. This why I am questioning whether I am doing it correctly. It just does not make sense that a 1UZ should rev higher than a B16, yet the 1UZ has a 6500rpm redline from factory. I have never driven anything UZ powered so I do not know its characteristics.

I apologize for the long type. I have always written long-winded.

Sidenote: Lex, which gen heads are you using for your hybrid and why?

Hey, God bless you all.

Jacob

 

[Lextreme II]

Q # 1:The 2uzfe heads have larger chamber and thefore, the 1uz heads will not bolt into the 2uz bottom. To solve this, thicker gaskets or machine the 1uz heads slightly larger chamber

Q # 2: These two links would help http://www.lextreme.com/stroke.html http://www.lextreme.com/rods.html


Cubic Inch and bore/stroke ratio

 

[jacob]

Hey Lex,

Thanks you quick reply and info.

Lower compression pistons could be the best way. At least it would be better if you are going with boost.

Bore/stroke ratio is not the same as rod/stroke. Rod/stroke determines where the power will be in the rpms and how high or low an engine will rev. I understand there are other things, but generally this determines where the engine is happily spinning. Some people mistake the oversquare/undersquare factor for the engines rev-ability. Most high revving hondas are undersquare or square, but they usually have great rod/stroke ratio. It has been said the idea r/s ratio for race (save F1) is 1.75. The honda B16 is 1.74 that is almost perfect. The 1uz is an over achiever with 1.76. R/S ratio is obviously not the only way to get a rev happy engine. Take the 4age spinning out to 8k, it has a 1.58 r/s ratio. On the opposite end is a Ford 5.0, it has a 1.70, from factory there is no point in going past 5k.

In the end it all depends how the engine is setup. Toyota chose to restrict the ability of uzfe to rev high. Why it set this engine up so backwards, I just do not know. The good news out of all this is the next time some one says setting up your 1uzfe to rev to 9k and beyond will drastically shorten the life out of your engine, you can go ahead and correct them because being able to rev it to 9k is how it should've been from factory.

I think with the right head work and valvetrain components the 1uz revving to 9k will make alot more power and be alot more happy doing it.

God bless you all!

Jacob