V35A-FTS V6TT teardown by Dave (Dave's Auto Center)

[GR8Santini]

I wish I was smart like you guys.

This really is a remarkable forum of great owners, & I learn something here every time I visit. Good folks.

 

[ultane]

…I learn something here every time I visit. Good folks.

So. Do. I.

 

[basicxj]

I wish I was smart like you guys.

If we were to touch on a topic that lights you up and you weighed in, I am sure we'd learn a thing or five .

 

[Calokie]

They need to have these blocks and cranks checked on a cmm. Either the machining is imprecise (geometrical) or geometry changing too much under load (flex) and heat cycles. Precision is expensive, opening tolerances saves money, until it doesnt. Manufacturers try to find the sweet spot.
I've watched a manufacturer (not toyota) disable the final gauge for cranks coming off the line in order to keep production running. If an engine seized during the cold test, they would take it offline and repair it.

After watching the latest video and seeing the chatter marks, I suspect the crank is the issue, possibly due to the structural design around the journal seats. That could explain why the hybrid models are unaffected, since electric motor assist reduces the load. However, the Japan-market non-hybrid GX550s are reportedly unaffected as well—or at least that's what we've been led to believe.

 

[MSINAL]

After watching the latest video and seeing the chatter marks, I suspect the crank is the issue, possibly due to the structural design around the journal seats. That could explain why the hybrid models are unaffected, since electric motor assist reduces the load. However, the Japan-market non-hybrid GX550s are reportedly unaffected as well—or at least that's what we've been led to believe.

Good observation, could be the crank flexing in the high torque band, low rpm. Could be both crank and block flexing. Could be so many things including metallurgy, heat treating, or machining tooling insert replacement intervals (deformation due to high carbide insert forces against flexible workpiece). Regardless, the uneven wear on main journals is a massive red flag, more like a nuclear radiation leak alarm.
This is potentially a suboptimal engine design that can only be fixed by detuning it, or boosting with hybrid motor at lower rpms. It would be enlightening to learn the true root cause(s).
If the video guy could put that crank on centers and measure total indicator runout, I bet it would show the crank is bent.

 

[GR8Santini]

The thrust bearing wear is exactly what I’d expect from a boosted aluminum block / steel crank that was very overheated. Once the lower girdle warped nothing is going to look true.