How to kill a 1UZ Question?

[Rawal4x4]

Well, we run a 1UZ on a Land Cruiser FJ40 for desert racing with 4x4 and locked rear diffs. Recently, after 4 successful rally raid completions on our fifth heavy duty race we managed to finally kill the 1UZ. About 10 kms from the finish line, we heard some crackling sounds from the engine and lost oil pressure and all power within a matter of seconds. The engine would start initially but was unable to move the car on the sandy track. The left cam seal was leaking oil and though we topped up the oil, the crank jammed up soon afterwards. Mainly my fault though because I was running it in second gear essentially all the way and rev cutting it a lot by the end. It was a great run for this 1UZ but it had to end somehow

We are still in the process of analysis. Lifted cam covers to find that while the right bank seemed well lubricated the left bank cover was kinda dry and dark. Looking for clues as to what may have gone wrong and essentially what would be the best solution as we slowly dig in deeper...

More on the build and the past here : http://www.race-dezert.com/forum/threads/vintage-baja-fj40-build-for-desert-racing.94557/

 

[Rawal4x4]

BTW here is the "How to kill a 1UZ video", sorry for bad quality but it conveys the situation well : https://vimeo.com/87633051

 

[Rawal4x4]

Here is a launch video, about an hour before detonation : https://www.facebook.com/photo.php?v=10151989390297825&set=vb.543582824&type=2&theater

 

[BlackUZZ31]

Oil surge, with the sustained high RPM running probably had a lot of oil up in the heads and a lot less in the sump!

If you want to do that kind of thing a dry sump setup would be ideal, second best would be a big accusump!

 

[Rawal4x4]

Exhibit 1 : The Seventh Rod - RIP

 

[Rawal4x4]

Analysis so far: Cam Shaft seal leaked after continued high rev action, oil pressure dropped, big end or piston seized due to oil starvation breaking rods. Continued efforts to restart the engine and finish resulted in additional crank / block damage. All happened within a matter of seconds at the *** end when the focus was on finishing the race and by all counts engine was running in steady state.

 

[XR8tt]

There are other gears in gear box ??

 

[Rawal4x4]

There are indeeed! But then again this is not a thread about how to make a 1UZ last, is it

 

[XR8tt]

You said looking for clues what went wrong ?? IMO too much consistent high rpm .. Larger baffled sump . Oil cooler .. And a mirror !!

 

[Zuffen]

As an old desert racer my first thought was change gears!

No engine can sustain that sort of treatment if it isn't a built race motor.

What was it revving at? My guess is 5-6,000pm.

A small oil leak won't cause it to loose enough oil to run it dry.

These engines are fairly bulletproof but an engine with 100,000+ k's on it isn't something you can abuse to that extent.

 

[Rawal4x4]

IN addition to the rods we broke and the block we seem to have destroyed:





I am surprised that I am told that the heads may be cracked / damaged too, would you agree? Pics, not showing up here, but do please do take a look and advise, Thanks!

 

[XR8tt]

How much is another engine ? A latter vvt built engine with 'forged' rods and pistons would be a killer .. Or non vvt with forged assembly and use some parts as spares ??

 

[Rawal4x4]

How much is another engine ? A latter vvt built engine with 'forged' rods and pistons would be a killer .. Or non vvt with forged assembly and use some parts as spares ??

Another engine would be around $800 complete and about $600 without wiring and AFM etc. Always doable, but I want to put together the parts from two engines I have at hand and get one going.

Also our team has not gotten down and dirty with the 1UZ internals as yet and this is as good a time as any because as we move towards putting on a turbo or two on these machines we are going to need these skills and knowledge. As yet there is some disagreement within our camps as to a composite (head and block from different engines) stock motor being as rugged as a fresh second hand piece!


Here a vote of thanks for the wonderful team at Lextreme for all their inspiring work!