Was the 2UZ-FE an improvement on the 1FZ-FE? (1 Viewer)

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I wonder why Toyota insisted on an iron block for the 2UZ, but then have it weaker conrods. Iron blocks might technically be stronger, but only if you’re making crazy power.
'Development Potential'?
 
I wonder why Toyota insisted on an iron block for the 2UZ, but then have it weaker conrods. Iron blocks might technically be stronger, but only if you’re making crazy power.

Iron blocks are cheaper to manufacture. Way cheaper.

I figure the 2UZ development went about like this: Mgmt gave some engineers the great 1UZ, then said, "get me more torque, make it cost 2/3 as much, and make it just as reliable." They left for some sake bombs and came back to the 2UZ plans.
 
Iron blocks are cheaper to manufacture. Way cheaper.

I figure the 2UZ development went about like this: Mgmt gave some engineers the great 1UZ, then said, "get me more torque, make it cost 2/3 as much, and make it just as reliable." They left for some sake bombs and came back to the 2UZ plans.
Hm yea I suppose the Japanese bubble economy was coming to an end when the 100 series was being developed.
 
Are comparing only LC engines or overall Toyota engines? Cause then they are a few more engine greats that come to mind.... But I think I might be barking up the wrong tree. Lol
 
Cast iron blocks are way stiffer than aluminum which helps them last longer. Also the newer UR engines are having headgasket issues some are attributing to the aluminum block since it heat cycles faster than iron.

What you say about aluminum is true however with good normal maintenance those 3UV have been known to run forever as well.

I believe there have been few 1 million mile 3UV engine's as well.
 
Cast iron blocks are way stiffer than aluminum which helps them last longer. Also the newer UR engines are having headgasket issues some are attributing to the aluminum block since it heat cycles faster than iron.
AFAIK the 1/3UZ never bad head gasket issues though. Maybe it’s more likely to happen when you have an Al block engine in a heavier truck?
 
AFAIK the 1/3UZ never bad head gasket issues though. Maybe it’s more likely to happen when you have an Al block engine in a heavier truck?
I’ve never heard of this either. Would love to know more.
 
I’m revisiting their thread since I continue to notice how 4.7s will have remarkably few leaks, even up to 500k miles, while a 1FZ over 200k will be coated in oil and in need of a reseal or even rebuild. Does anyone know what Toyota changed in the 2UZ to prevent the famous leaks seen in the earlier straight six motors?

I also see this to a lesser extent in the 5VZ vs 3RZ in the early Tacomas and 4Runners. Toyotas V engines just seem to retain their oil better. Am I into something or is it just happenstance..
 
I’m revisiting their thread since I continue to notice how 4.7s will have remarkably few leaks, even up to 500k miles, while a 1FZ over 200k will be coated in oil and in need of a reseal or even rebuild. Does anyone know what Toyota changed in the 2UZ to prevent the famous leaks seen in the earlier straight six motors?

I also see this to a lesser extent in the 5VZ vs 3RZ in the early Tacomas and 4Runners. Toyotas V engines just seem to retain their oil better. Am I into something or is it just happenstance..
Same with 3UR engines
 
I’m revisiting their thread since I continue to notice how 4.7s will have remarkably few leaks, even up to 500k miles, while a 1FZ over 200k will be coated in oil and in need of a reseal or even rebuild. Does anyone know what Toyota changed in the 2UZ to prevent the famous leaks seen in the earlier straight six motors?

I also see this to a lesser extent in the 5VZ vs 3RZ in the early Tacomas and 4Runners. Toyotas V engines just seem to retain their oil better. Am I into something or is it just happenstance..

UZ, VZ, and RZ are tight, but they aren't perfect. Rubber is still rubber, and it will take a set and leak. Each has a couple notorious leak points. Valve covers are common with age. They all eat rear mains with similar failure rates.

Their main reasons for being "tight" are the minimal opportunities for oil to get out, and most of those seals are in joints that work well. And Toyota's FIPG is some wickedly good stuff to boot. Toyota and Merc have some next level sealant chemistry going on.
 
UZ, VZ, and RZ are tight, but they aren't perfect. Rubber is still rubber, and it will take a set and leak. Each has a couple notorious leak points. Valve covers are common with age. They all eat rear mains with similar failure rates.

Their main reasons for being "tight" are the minimal opportunities for oil to get out, and most of those seals are in joints that work well. And Toyota's FIPG is some wickedly good stuff to boot. Toyota and Merc have some next level sealant chemistry going on.
Hm yea I’m still wondering what was different about the old inline-6 engines that may have predisposed them to more common leak areas and greater oil loss. I don’t hear about the valve stem seals or oil pan being such an issue on the V8s for example.
 
Both 2UZs will let me balance a coin on the engine while running. The one with 330,000 is actually a bit smoother than the one with 240,000 miles. Strangely the high mileage one doesn't leak or consume any oil The lower mileage engine does have VC leaks. Consumption for the one with leaks is about 1/2 quart between changes.

I cannot do this with my 80,000 mile 5VZFE.

The 2UZFE was used in the Tundra, Sequoia, 100 series, and 4th gen T4R. If more, I need to know.

 
The 2UZFE was used in the Tundra, Sequoia, 100 series, and 4th gen T4R.
But if not mistaken, in the '98 hundy before any of the others and the reason it was put in the others.
 
But if not mistaken, in the '98 hundy before any of the others and the reason it was put in the others.
That speaks well for it.
 
I’m revisiting their thread since I continue to notice how 4.7s will have remarkably few leaks, even up to 500k miles, while a 1FZ over 200k will be coated in oil and in need of a reseal or even rebuild. Does anyone know what Toyota changed in the 2UZ to prevent the famous leaks seen in the earlier straight six motors?

I also see this to a lesser extent in the 5VZ vs 3RZ in the early Tacomas and 4Runners. Toyotas V engines just seem to retain their oil better. Am I into something or is it just happenstance..
AFAIK the 1/3UZ never bad head gasket issues though. Maybe it’s more likely to happen when you have an Al block engine in a heavier truck?

Not sure if this addresses a point here, but the physics of straight six versus V8s means the long skinny straight six block is always going to be more inherently harder to seal from both oil leaks and compression gases.

A well manufactured aluminum block should be just as stiff and reliable as an iron block. The problem is, it is magnitudes higher difficulty to keep dimensional stability of an aluminum block during the manufacturing process.

I know a few high end custom engine builders that refuse to do aluminum block builds of traditionally iron block engines because the relatively short runs of custom aluminum blocks are so hit and miss for their standards. The major manufacturers (except BMW) have developed the technical means of making aluminum blocks for V-engines that turn out well.
 

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