Differences between 1uz models?

[ed]

I know the VVTI engines got much weaker rods, but i thought all before VVTI were the same beefy ones?

im not sure 'beefy' is the word

[Sciflyer]

I know the VVTI engines got much weaker rods, but i thought all before VVTI were the same beefy ones?

It looks like the change of internals corresponds to the first increase of CR around 1995, and the rods used here are apparently identical to the vvti ones

[ed]

your interpretation of that pic is wrong
th first rod is non vvti 1uz
the next 2 are vvti 3uz and/or vvti 1uz
the last is an eagle h beam rod

the non vvti engines have the same rods (bigger/heavier/dubiously 'stronger')

[GriZZly]

so theres no difference in rod strength between the 10 and 10.4 comp models??

cheers

[ed]

well i wouldnt go calling them 'strong' id just say theyre both as weak as each other

the vvti and 2uz/3uz are weaker still

[v8soarer]

the non vvti engines have the same rods (bigger/heavier/dubiously 'stronger')

I don't think that's right Ed. Hillbilly on Lextreme had a 95-97 engine and his rods were the skinny ones and they didn't like boost.



From:
http://lextreme.com/forums/showthrea...hillbilly+10.4

[ed]

bizzaro... theyre definitely the skinnier rod
i wonder if it was actually 'boost' or perhaps revs....

[MWP]

Hmmm, maybe they changed at some other time during production.
Interesting.

Would be nice to know when.

[Sciflyer]

The point i made in that very thread was (with some other info that was posted there) it *appears* that the change in rods came about with the other change in internals that corresponds with the CR increase around 1995

This is borne out by those 'skinny' rods in a 1995 engine

FWIW Mike was making less power than Justen is now when they let go (if you can call 450-480rwhp "less"

So although it is still far from conclusive, it does seem to add up.

[jeffro ra28]

I tend to beleive a rod breaks because it is detonating or over reving. That or it has an oiling problem and it gets hot around the journal and then breaks.

Stock rods tend to handle alot more power then people think if the tuneup is right

[Sciflyer]

correction, i believe it was 450-480rwhp

[v8soarer]

Here we go - the part number for the rods changes in August 94 and continues through to Sept 97.



This predates the change to the cams and I presume the comp by 9 months.

[Sciflyer]

My car is a 9404....hmmmm.......

Good info, it would be interesting to check that these dates correspond over other 1UZ models (Aristo, Celsior, etc) as the specs across the different models seem to change at different times according to Amayama.com (although obviously thats not a 100% reliable source...)

[MWP]

Do the fuel rail part numbers change on the same date?

[Sciflyer]

My car is a 9404....hmmmm.......

Good info, it would be interesting to check that these dates correspond over other 1UZ models (Aristo, Celsior, etc) as the specs across the different models seem to change at different times according to Amayama.com (although obviously thats not a 100% reliable source...)

Ok Aristo has the same date of change as Soarer (August '94), Celsior lists October '94, Crown lists August '95 as the change in rods....

The fuel rails changed in May '95

Getting back to the OP, i wonder how much *real world* difference in performance there really is between pre-'95 and '95-'97 engines, i doubt you could tell (certainly the figures dont suggest much), the real boost in power and torque didnt come until the VVTi introduction in '97