can you fit 2UZ pistons in a 3UZ?

[SuperRunner]

I searched, I couldn't find an answer, but just want to know if this could be done. I would love to make a 4.7 aluminum short block.

 

[Lextreme II]

UZFE Compatibility The answer is NO....

 

[SuperRunner]

Ok, I did look at that, but I wasn't sure if there still was a way.

What is the maximum bore size you can go in a 3UZ?

I would still like the 3UZ because I want a bigger motor than the 1UZ, but I need it to be lighter than the 2UZ.

 

[SuperRunner]

actually, why couldn't you fit 2UZ pistons in a 3UZ block. Sure, it is a little out of spec, but remember, toyota is over engineered.

Does anybody know the thickness of 2UZ cylindar wall?

In order to fit a 2UZ piston in a 3UZ block, you would have to bore it out about .06 over. Most anyone goes is .04 over, but I know of some people running more.

With a .06 over bore, the sleeve thickness would still be around .127. Is that not thick enough?

 

[SuperRunner]

Found this on an LS1 forum. Thier walls are thinner than ours to begin with.

I have an LS2 block and I had the sleeves sonic tested. The sleeves average .105" thick and it is a siamese block. I plan to bore it .060" which leaves the sleeves .075 thick which is plenty in my experience.

 

[Lextreme II]

LS2 is not 3uzfe.... Most people in here wont not recommend bore more then .02"

 

[SuperRunner]

but has anyone tried going .060 over before?

For example, 1JZ vs 2JZ head. For years people had said that the 1JZ head flows way better than the 2JZ head. Well, up until earlier this year, that is what people BELIEVED! It wasn't until someone actually flow tested the 2 and posted thier results so public eyes could see.

That is someowhat of a problem with any internet forum, it is mostly her-say until someone proves otherwise. And the people who actually do the stuff are usually not on the forums to share thier information. It is nice when someone actually offers proof.

So, until someone can either prove or disprove this, I am going to believe you can fit 2UZ pistons in a 3UZ without any problems.

Now I just need to get my hands on a 3UZ block, and a boring plate.

Anybody got a UZ boring plate they can lend me?

 

[SuperRunner]

JGTC 3UZ's are a 5.2L (bored out to max) hmmm.

 

[Lextreme II]

You can try 3uzfe with 2uzfe crank. Its not much gain.... However 3uzfe with 5.2 liter means the bore is 3.95" Without stroking its impossible to get. 3.95" means no sleeve.

3UZFE with 3.950" bore with standard stroke
Input Parameters Are the Following:
Number of Cylinders are = 8 to 1
Piston Diameter = 3.950 Inches
Piston Oversize = 0.000 Inches
Engine Stroke = 3.250 Inches

Computation Results:
Computed Engine Displacement (CID) is 319
Computed Engine Displacement (Litres) is 5.2
Computed Engine Displacement (CC) is 5221.1

3UZFE with .06" Over Bore:
Input Parameters Are the Following:
Number of Cylinders are = 8 to 1
Piston Diameter = 3.640 Inches
Piston Oversize = 0.000 Inches
Engine Stroke = 3.250 Inches

Computation Results:
Computed Engine Displacement (CID) is 271
Computed Engine Displacement (Litres) is 4.4
Computed Engine Displacement (CC) is 4433.8

 

[SuperRunner]

Yes, but I will also be using the 2UZ crank

 

[SuperRunner]

ahh, I messed up a little on my conversions. I was thinking of removing .060 of material all the way around which would actually be .120 total, but even with boring a 3UZ .120 over, there is still more material on the cylinder wall of the 3UZ than there is on a LS1. I will have to do a little more thought and research on this.

 

[rarson]

The problem is not the wall thickness, it's the sleeve thickness. The stock sleeves are a certain diameter, not much thicker than the bore itself. There is still aluminum meat between the cylinder sleeves. The maximum outer diameter sleeve size will have the steel sleeves touching each other. Supposing that you DID fit the biggest sleeve you could, you could probably go up to at least 98mm bore.

The point is, yes you could fit a 2UZ piston into a 1UZ or 3UZ. The question is whether or not that would require new sleeves, and the answer is probably. Because the sleeves are thinner toward the bottom of the cylinder and cannot likely withstand more than .040" overbore.

 

[rarson]

IMO, since sleeves aren't the most expensive thing in the world, you should just get a set and sleeve a 1UZ block. 3UZ's are much harder and more expensive to come buy. You'd probably actually save money sleeving the 1UZ than buying a 3UZ (then again, maybe not, but it'd still probably be close).

 

[SuperRunner]

Seems that sleeving can actually be pretty expensive.

For the LS1/LS7 motors, it looks like it is about $2300. I wonder if they would extend that price for the UZ motors.

If they would re-sleeve the 1UZ for the same price, that would be worth it. Still would need 2UZ or 3UZ heads.

 

[Lextreme II]

Super,

If you don't mind the weight, why not putting in a 2uzfe motor with 1, 2 or 3 uzfe heads?

 

[SuperRunner]

the car only weights 2400 lbs as it is, and I would like to get it down to 2200. Weight is a big factor.

 

[SuperRunner]

I might do the 2UZ for now, and later replace it with a modified 1UZ or 3UZ, Oh, and I wouldn't mind stroking it too.

 

[Lextreme II]

We can make you a 4.7 aluminum block but no guarantee on the toughness of it. We can resleeve the 1uzfe block with 2uzfe bore spec but you will have very thin wall support and extremely weak supporting structures.

 

[SuperRunner]

Ok, what about the 3UZ, is the support structure any thicker?

What is your cost?

 

[Lextreme II]

Super,

All 1uzfe and 3uzfe have the same block just different sleeve size. So, 1uzfe resleeve is the same as another other uzfe engines.