Lightweight Pistons and Rods starting in 1995

[JBrady]

Here is a pic posted by hillbilly of a bent "skinny" rod and a side view of the lightweight pistons that arrived with these rods. The design is similar to lightweight forgings on high RPM race engines but does not look very good for boosted applications especially since they are NOT forgings.

Excerpts from Lexus courtesy of John Cribb. These changes arrived on the 1995 LS400 and include the skinny rods, light pistons and lightened crankshaft

 

[Lextreme II]

For the SC400, the skinny rods started 1996.

 

[Fasteddie]

Looking at Hillbilly broken rod, presenting the rods twin brother...similar cracks !

 

[earthman]

G'day to all in lex-land, I have a 1996-97 1uzfe Toyota Celsior motor about to go into my vehicle.

How concerned should I be?

Is this becoming a common problem?

Under what conditions did they brake (turbos or blowers?)?

 

[jibbby]

Earthman, just don't push over 300whp and you should be good....


Man, that rod got worked over big time...I would hate to see what the engine block looks like....at:

 

[4000GT]

Umm I know people running over 500WHP and they are fine on stock motors... ? Even on here arent people running up there on stock motors? Justen springs to mind.

 

[Lextreme II]

Justen has the older version so its little tougher. However, I might run a M112 in my 1995 LS400 just for fun. We will see what happen. I think 400 rwhp should be ok.

 

[4000GT]

oh these are the later rods... gotya.

 

[earthman]

Thanks for the reassurance gents, I don't plan on doing much beyond stock (yet!).

The breaks look pretty savage, was there much damage to the block, crank or oil pan after the rod kicked the bucket?

 

[drifty325i]

If the car is tuned correctly the 95+engines will be fine with mild boost. 400rwhp easy

 

[Hillbilly]

If the car is tuned correctly the 95+engines will be fine with mild boost. 400rwhp easy

A lot of guys who were in the know said the same thing to me, shame they were all wrong and the motor lasted a week.
Oh and it was tuned right, from my experiance you cant make 400 RWHP and expect it to last long. Better to be safe than sorry I beleive, either keep the boost down below 8psi or change the rods for earlier ones and fit forged pistons.

BY the way after I munched the Rod and piston my block and crankshaft had no visiable damage, lucky me I guess

 

[jibbby]

Dudes, I researched this and it is has been posted on several threads...

92-95 1uzfe's 500whp is doable with stock internals and a good tune..

95-up - 330-350whp the rods fail... That has been documented on several motors...

 

[Fasteddie]

agree to that !...those are my findings aswell....
I would even say the 1UZ STOCK design is limited to 550 rwhp....(stock cams, stock inlet, stock head (flow), etc...).....

(unfortunately I can't show dyno results that prove that....but for my 1UZ ls400 I hope to provide those soon...)

 

[4000GT]

I have seen a stock (except ECU) VVTi 1UZ on an engine dyno make just under 300HP. I would be amazed if the threshold for breaking rods was 30HP more... we are talking about 8 pots here! Its not massive load per cylinder.

 

[drifty325i]

Theres no way this is true, they handle alot more than that

"95-up - 330-350whp the rods fail... That has been documented on several motors..."

 

[4000GT]

Yeah it seems very odd when other NA turbo motors like the SR20DE make over 400WHP on a 4 cylinder...

 

[jibbby]

Yes way Drifty.... 300-350whp and not bhp I have read and seen 97, 98 UZ motors destroyed from rod breakage... Just use the search function on this forum and you will find a few testimonies and pictures...

It is shame that the rods are so weak on the newer motors, but it is what it is...