1996 ls 400-interference or not??
- Thread starter mossyoak
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The 1UZFE EGR Delete Kit is available for sale here.
The 1st gen 1uzfe (1990-1994) is NON-interference. The LS400 got a fairly revised 2nd gen 1uzfe in 1995 (USDM) and that was the beginning of the INTERFERENCE 1uzfe engines. The SC400 received the engine sometime in 1995 and officially for the 1996 model year.
The engine had a 0.4 point increase in compression from 10.0 to 10.4 to 1. Lightweight crankshaft, piston rods, pistons and pins were introduced. These are the infamous "weak" rods. There was a minor change to the camshafts and on the LS dual tube exhaust manifolds (SC400 continued through 2000 with single tube log exhaust manifolds). The "official" power increased from 250hp/260tq up to 260hp/270tq. In actual practice the engine gained a good 30hp.
Interestingly even though the engine became interference the service interval on the timing belt went from 60k miles to 90k miles.
Excellent post and info with the BEST learning device... pictures!
FastEddie, what conditions failed the 96 rods you show other than the stated 6psi boost? RPM? Detonation? Pre-ignition? Other?
On the 4 rods shown twisted: I am assuming a test was devised to test strength. The first 3 rods appear to be true forgings with the parting line visible. The 1uz rods are powdered metal construction which combined with their very lightweight and definitely less robust cap concerning to say the least. Also, powered metal rods are usually "crack" type for the caps so the metal is engineered to be "brittle" as shown in the pictures (let's call them glass rods)
Which specific engine are the 3s rods from? The 3S-GE or GTE?
Huh? Better explain yourself there John.....
WDoherty
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it is interference for ls400 95up
JBrady
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The 1st gen 1uzfe (1990-1994) is NON-interference. The LS400 got a fairly revised 2nd gen 1uzfe in 1995 (USDM) and that was the beginning of the INTERFERENCE 1uzfe engines. The SC400 received the engine sometime in 1995 and officially for the 1996 model year.
The engine had a 0.4 point increase in compression from 10.0 to 10.4 to 1. Lightweight crankshaft, piston rods, pistons and pins were introduced. These are the infamous "weak" rods. There was a minor change to the camshafts and on the LS dual tube exhaust manifolds (SC400 continued through 2000 with single tube log exhaust manifolds). The "official" power increased from 250hp/260tq up to 260hp/270tq. In actual practice the engine gained a good 30hp.
Interestingly even though the engine became interference the service interval on the timing belt went from 60k miles to 90k miles.
Lextreme II
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This what JBrady was trying to say about "Weak Rods"
Fasteddie
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uhh....yes, the '96 (UCF 20) Rods are WEAK...i can tell you first hand !
This happened with only 6 psi from a T88-34d on a '96 4.0 1UZ:
We also tested other rods:
lefth to right:
2jz
3s
7m
1uz UCF-10
As you can see, if you wanna go save: UPGRADE !
...or calculate that you will have to do it sooner than you like....
This happened with only 6 psi from a T88-34d on a '96 4.0 1UZ:
We also tested other rods:
lefth to right:
2jz
3s
7m
1uz UCF-10
As you can see, if you wanna go save: UPGRADE !
...or calculate that you will have to do it sooner than you like....
JBrady
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uhh....yes, the '96 (UCF 20) Rods are WEAK...i can tell you first hand !
This happened with only 6 psi from a T88-34d on a '96 4.0 1UZ:
We also tested other rods:
lefth to right:
2jz
3s
7m
1uz UCF-10
As you can see, if you wanna go save: UPGRADE !
...or calculate that you will have to do it sooner than you like....
Excellent post and info with the BEST learning device... pictures!
FastEddie, what conditions failed the 96 rods you show other than the stated 6psi boost? RPM? Detonation? Pre-ignition? Other?
On the 4 rods shown twisted: I am assuming a test was devised to test strength. The first 3 rods appear to be true forgings with the parting line visible. The 1uz rods are powdered metal construction which combined with their very lightweight and definitely less robust cap concerning to say the least. Also, powered metal rods are usually "crack" type for the caps so the metal is engineered to be "brittle" as shown in the pictures (let's call them glass rods)
Which specific engine are the 3s rods from? The 3S-GE or GTE?
WDoherty
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its amazing justen has been able to pull so much power and high boost out of the later weaker rod engine when everyone else has had destruction and those rods look tiny compared to the 90-94.
jibbby
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Those busted rods are rediculous...
You got to go with the early model 92-94 1uz-fe motors as they are the stoutest out of the bunch... Or change those toothpic rods if you plan to boost the later model uz motors...
You got to go with the early model 92-94 1uz-fe motors as they are the stoutest out of the bunch... Or change those toothpic rods if you plan to boost the later model uz motors...
Fasteddie
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Conditions:
We found no signs of detonation, we applied no pre-ignition, stock ecu only fuel adjustments with an E-Manage.
We think it was just the material weakness with to much stress on the rods.
Used turbo: T88-34d on 6 psi...although we also had moments of 8 psi.
The 3S rods were GTE rods (aren't the GE and GTE the same ?)
We are now upgrading to Pauter rods....which was planned anyway, but came earlier then hoped for...:twak:
We found no signs of detonation, we applied no pre-ignition, stock ecu only fuel adjustments with an E-Manage.
We think it was just the material weakness with to much stress on the rods.
Used turbo: T88-34d on 6 psi...although we also had moments of 8 psi.
The 3S rods were GTE rods (aren't the GE and GTE the same ?)
We are now upgrading to Pauter rods....which was planned anyway, but came earlier then hoped for...:twak:
Fasteddie
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...we also tested a brand new (50 km) 3UZ rod:
XR8tt
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Is twisting a rod have anything to do with what forces are going on IN engine?? I can see it has to do with strength esp torsional ...
From VVT on they are interference...
Rods can live well with GOOD tune...
We have some good tuners and Ecu's down here....
From VVT on they are interference...
Rods can live well with GOOD tune...
We have some good tuners and Ecu's down here....
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Fasteddie, what RPM's were you turning when these rods decided to let go?
Fasteddie
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All stock ECU...so max. 6500 rpm...
I agree on a GOOD tune....but we couldn't find any error in the things we have done (no detonation etc..)...if anyone has an idea what went wrong, please chime in...
I agree on a GOOD tune....but we couldn't find any error in the things we have done (no detonation etc..)...if anyone has an idea what went wrong, please chime in...
jibbby
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I really did alot of research on the weak rods over the years and found the breaking point to be right around 330-350whp for some...Fasteddie is not the only one who has reported busted rods from pushing to much HP's...
I have not been able to find one blown 92-94 1uz-fe motor, and I did see one make 500whp on stock internals... Rods make atleast 150whp difference in these motors from my findings...
It's really a shame because all the new UZ motors have higher compression and put out better HP numbers then the early model 1uz-fe's... Really I must ask, what was the toyota design engineers thinking? (I guess they were thinking no one would boost the stock motors) In any event why down grade the rods thru the years when producing a motor with more power? They had it right the first go around...
I have not been able to find one blown 92-94 1uz-fe motor, and I did see one make 500whp on stock internals... Rods make atleast 150whp difference in these motors from my findings...
It's really a shame because all the new UZ motors have higher compression and put out better HP numbers then the early model 1uz-fe's... Really I must ask, what was the toyota design engineers thinking? (I guess they were thinking no one would boost the stock motors) In any event why down grade the rods thru the years when producing a motor with more power? They had it right the first go around...
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Lextreme II
Just call me "Lex"
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Due to the weak rods from 1995 to 2006/7 we decided to have some forged H beam rods made specifically for that purpose. Our rods are extremely affordable and can handle up to 1000 rwhp with 7/16 L-19 bolts. We under rate our hp on purpose. They are direct bolt on to the stock crank and pistons. Balancing the whole assembly is needed.
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Huh? Better explain yourself there John.....
jibbby
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What's to explain...
92-94 1uz-fe stock internal motors have been shown to hold up to 500whp on the stock internals.. Seen it done twice in Australia according to reports.. I think one guy on this forum is close to that output as well..Forgot the user name...
Many 95-newer UZ motors have been reported to fail around 350whp and sometimes less..Rod failer was always the culprit....
My baked logic - 500whp minus 350whp = 150whp...That's where I base my finding and logic and it could be more.....All my finding were based from actual found experiences from UZ motors that were blown or in use... No guess work or assumtions were made on these statements... It is what it is...
92-94 1uz-fe stock internal motors have been shown to hold up to 500whp on the stock internals.. Seen it done twice in Australia according to reports.. I think one guy on this forum is close to that output as well..Forgot the user name...
Many 95-newer UZ motors have been reported to fail around 350whp and sometimes less..Rod failer was always the culprit....
My baked logic - 500whp minus 350whp = 150whp...That's where I base my finding and logic and it could be more.....All my finding were based from actual found experiences from UZ motors that were blown or in use... No guess work or assumtions were made on these statements... It is what it is...
XR8tt
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Was it failure due to rpm or power ??
The lighter rods / rotating assembly makes engine far more responsive, adding alittle more compression helps .. Strange ? A n/a 2J with 15 Lb boost runing alcahol can run 8 second pass in RX7 I figure around 800 h.p ..Yet the 1UZ was built different, I guess it wasn't meant to be leaned on. Just used as an old mans car...
The lighter rods / rotating assembly makes engine far more responsive, adding alittle more compression helps .. Strange ? A n/a 2J with 15 Lb boost runing alcahol can run 8 second pass in RX7 I figure around 800 h.p ..Yet the 1UZ was built different, I guess it wasn't meant to be leaned on. Just used as an old mans car...
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