So about a month ago my oil pump failed and caused my block to seize up. I had the engine completely taken apart and had the block sent out to a machine shop. Unfortunately, the block has a crack on one of the surfaces where the bearing goes. Time for a short block replacement.

Now I know you're probably thinking "why doesn't he just get an entire used engine?" Here is the answer. Just a couple months back I had to rebuild the heads due to a timing belt break. I replaced the water pump and all tensioners and belts during the process so the heads have about 100 miles since rebuilt. So preferably I'd like to keep the heads.

As of lately I have realized how incredibly difficult it is to find a replacement short block everywhere online and any place I look nationwide. They only sell them in complete engine sets at the junK yards. Prices range from about $2900-$5000 for a used 3UZFE.

Lately I've been tossing around the idea of swapping in a 2UZ short block with the 3UZ heads for bigger displacement. A W58 will be mated with the 2UZ as well.

Has anyone had any experiences with a 4.7 liter 2UZ swap on 3UZ heads? Any pros or cons? Any thoughts or advice is very welcome. My car is a 2001 GS430.

 

Sounds like a great idea, I hope you find a way to make it work! The only thing I would recommend is to stick with a 2UZ block that has VVTI so you don't lose the extra oil passages you need for your heads.

These are the models with a 2UZ VVTI

• 2005–2009 Lexus GX 470
• 2006–2007 Lexus LX 470
• 2005–2009 Toyota 4Runner
• 2006–2011 Toyota Land Cruiser
• 2005–2006 Toyota Tundra
• 2005–2009 Toyota Sequoia

 

Sounds interesting. What are your plans for tuning?

 

go to lextreme they do stuff like this...

 

I didn't give much of a thought to what I will be doing for tuning. I was hoping install the block and see how it runs so I can further identify probles and then provide solutions.

I've been keeping in touch with David at Lextreme. He's done the conversion before but I wanted to see if there were more people with experience on this who can help guide me in the right direction. The only reason I'm thinking about doing this is because the block on my current 3UZ that seized and cracked. Finding a replacement 3UZ block is virtually impossible.

 

Sounds like it would be sweet.

Any Idea of the stock max rpm and compression ratio of the 2uz vs 3uz?

 

It is doable and Lextreme is your best source for knowledge.

I am curious though.

How many miles on your GS?

How many miles were on the timing belt that broke?

 

At what milage your oil pump failed?

 

There were about 180k miles when it broke. When I had bought the car it had about 160k. The previous owner had told me that the timing belt had just been done but had no records.

 

It failed at 180,100 miles. Almost less than 100 miles after replacing the timing belt and rebuilding the heads.

 

Wow. I thought these engines were stout. .... I just bought a 2003 170k mile gs430. And I just replaced the timing belt since it was never done. It still looked new....

But a bad oil pump? Maybe this guy before you didn't change the oil?
Just sounds very peculiar...

 

It was the original pump. Believe me it was time. I should have replaced it when I did the timing belt and water pump.

 

Even at 180k i'm shocked that belt broke on you. These timing belts are one massive pieces of rubber

 

It happened. The service interval for these guys is every 80,000miles. I would definitely recommend sticking to that if you dont want to risk breaking it then spending the extra thousand or two to replace bent valves on the heads.