Destruction of Thrown Rods

[jibbby]

WOW, nice comparisons pics Lex..... Yeah the 2uz-fe rods look like they could bend or break like a twig...What was Toyota thinking with those sorry arse toothpic looking rods?

The early model 1uz-fe rods look much more stout compared to all the others, excluding the forged rods of course.....:fing02:

Question - Typically when the rods fail on these motors do they bend or snap at the weakest center point of the rod or do they usually fail at the top and or bottom circular connecting ends? I would assume they fail at the center point in mostly every case, is that correct?

Those forged rods look fat enough to handle twice the horsepower as the 2uz-fe rods, nice!!!!:Eyecrazy:

 

[jibbby]

Jibby,

I had posted answers to the same questions a number of times, but it has been so long that I can't remember if it was here or on Tundrasolutions...so here goes:

Was running a TRD piggyback that was designed for the TRD SC, so I can only assume it was taking out the right amount of timing under boost. I had another box taking out 6 more degrees of timing to accomodate the nitrous shot. Wide-band O2 system stayed around 12.5 (although 11.5 to 12 would have been more safe, 12.5 isn't exactly lean) fuel pressure was around 52 psi. Have a nitrous controller that was set to come in from 0 to 100% over a 2.5 second time frame, 93 octane gas and alcohol injection. Never heard any detonation, and of course, I'm presuming the knock sensors were working.

Had about 23/25 runs on it before it let go....like I said before, after seeing the carnage, I'm totally convinced that motor is not made for that kind of stuff. Especially for that kind of weight.

However, the new motor is....) just haven't had time to fool around with it yet....

Wayne

Wayne, It sounds like you were tuned in on it......Those rods surely look weak enough to fold at your 500bhp mark.... Nice effort anyway and balls to give that engine that kind of fortitude test...:smoker: Sounds like something I would try and do if given the opportunity...

 

[striker]

and there was no hint that maybe something else was at fault?

I mean is it really the shot that killed it, or was it premature(if at all "pre" in this install) wear? which could have been fixed before the big bang, big end bearings and or oiling perhaps?

the Honda d16 on ITB's and revs threw a rod, but after searching it seemed the big end bearings where the blame of the big bang and not the revs or power persee, if we had rebuild the motor earlier (race engine) it wouldn't have happend. costly leason learned there... the same build engine is now doing more power than before without problems but gets new rings and shells quite often.

grtz Thomas

 

[rytherwr]

Yeah, Jibby...know what you mean...I never was very smart when it comes to taking it easy on motors. ) This link will show you lots of stuff, especially how and where the rods broke...you can see that pretty much all of them broke down near the big end. Enjoy....http://www.lextreme.com/tundra.html

Wayne

 

[jibbby]

Yeah Wayne, I saw the break at the bottom ring earlier on with those pics and was wondering if the different sized center portions of all the different Xuz.. rods really make a difference? It appears to me that all the top and bottom ends of all the different rods look almost identical and equal in strength... It appears that the bottom ends of all the rods are the weakest points as illustrated in your destruction pic's and if that is the case with all the Xuz.. rod failures then one must wonder is one Xuz.. rod really stonger then another just because the center portion of the rod is fatter?...Including the forged ones... Do you see what I am getting at?

Something is not as it seems?

Stiker I hear you....I think the use of nitrous in general really jolts the engine as it does not come on gradually like normal boost or N/A power..It's a whole different beast, and that is why it is commonly known that Nitrous wears out engines in a hurry, especially the smaller ones...

 

[rytherwr]

Heck, Striker, motor only had around 14K miles on it....when I pulled it apart, rod and main bearings were fine, oil pressure was always where it should be as was the heat gauge...computer won't let engine rev past 5300 rpm, so it wasn't over-revving.....just wasn't made for the abuse....as I said before....my nitrous controller was set to go from 0% to 100% in 2.5 seconds...no shock there...2.5 seconds is a very long time to bring in 150 hp....if you don't believe me, have someone time you while you hold a red hot piece of steel in your hand....2.5 seconds is a LONG time....)

Wayne

 

[striker]

According to this topic, increase was 150hp in 2.5 seconds thats not to uncommon now is it? the Bike engined car (bec) crew are turning from 0 to 200+ hp in 2.8seconds in which they cover 0-100 in 2nd gear
maybe it is that hammerfall but due to revspan covered in that 2.5seconds which would lead back to TORQUE and lot's off it at the wrong moment/enginespeed.

sorry thinking out loud here.....

anyway the New stuff certainly looks the buisness!

grtz Thomas

 

[stevechumo]

Wayne,
It doesn't matter how you tuned your engine, the rods will break under extreme abuse for sure. The pistons might not get any dents or blown due to the correct tuning, but nothing lasts forever. I'm not into NOS but I've been told by the professionals that NOS should only be used at WOT.

 

[cribbj]

Hmmm, NOS is one of the most commonly used methods of getting a big laggy turbo spooled up for a good launch at the strip. That and of course using a 2 step to get a load on the motor so there's some real exhaust flow.

IIRC, on their racecar with the 92 or 94mm(??) turbo, BoostLogic juice their motor "only" to get the car launched, then they shut it down, while Titan hit their motor with a big shot at launch, then continue on the juice all the way down the run.

 

[rytherwr]

Some great points....pls don't let the 5300 factory rpm confuse the issue...WOT can and does happen at 1000 rpm...so nitrous application wasn't the issue...in fact my system is activated by a microswitch under the accelerator that won't engage until I am at WOT. John is right...lot's of turbo folks use NO2 as a spooling agent to spin up the turbo's quickly from launch, use a window switch to shut it down after spooling and run just the boost from there. Others do just as he said, hit that sucker from launch and run it all the way through. If you aren't using some type of nitrous control, it is a huge hit that shocks the tires, chassis and engine. If you look at a purpose-built nitrous engine, you will find some pretty hefty forged internals and as well as aftermarket blocks, etc. If you pay attention to the basics and have good equipment, nitrous is a very safe and comparably affordable way to go from point a to point b in a hurry.

Wayne

 

[jibbby]

I've been hammering out 150 nitrous shot on stock 1uz-fe internal engine for over 4 years now....I can't complain, it really gets my car moving for sure... Engine is showing signs of wear though...

 

[rytherwr]

Do you have the bigger rods and how much do you think you are putting out at the flywheel and what does that thing weigh?

 

[jibbby]

Rytherwr - No bigger rods, no internal engine changes or forgies on my stock 1992 1uz-fe.....I've been delivering approx. 300whp and 500 ft pounds of torque for over a year on it now, before that just a 100 shot..... I had blown the stock SC400 auto tranny when I increased to the 150 shot, I have broke the rear spindle, I had to rebuild and re-balance the drive shaft once already but as far as the motor is concerned it continues to pur...Some signs of ring wear though... No progressive nitrous shots either just a 150 blast usually engaged in second gear only because of the traction problems.....

Weight hmmm?...It's a stock SC400 minus 300lbs or so, what ever that is...It's basically heavy....

 

[XR8tt]

Turbo's seem about the easiest on rotating assembly ...
The only time there's issues ?? Is when boost comes on too strong in lower rpm....I guess this is where N20 can be an issue... Maybe staged to run lower h.p at lower rpm then more at say ?? Over 5000 rpm ????


Would it be a good time to say I have some second hand 1UZ rods ???? Lol....

 

[jibbby]

1uz-fe rods seem very stout, infact I've been researching on several forums these last couple of day about these motors throwing rods...Report is I found none on the 1uz's... 2uz and 3uz I found a couple though...

You may melt the pistons but the 1uz rods are fairly stout... 1uz-fe motors have solid cranks, good rods, but the pistons are likely to fail first, melt or crack..

 

[Lextreme II]

Jibbby,

You and I need to take a ride my friend's juckyard and you will see why 95 and up uzfe rods are so weak.

 

[stevechumo]

So you think it's safe for my '95 to run from 450-500 bhp? If it's not, then it's weaker than a Civic. A 4 banger Civic's rods can take the abuse 100% more than stock safely.

 

[Lextreme II]

I think SC400 start from 1997 with weak rods but need to confirm. However, LS400 is 1995. Remember, LS is always get the latest and the greatest first.

 

[jibbby]

Now Lex...Now don't start a forum weak rod panic...

Steve, just make sure your tuned right... 500bhp is asking for alot out of your stock SC4? That means you will have to go with larger injectors, a built or properly cooled tranny, fuel pump, ECU, etc.. What's going on with your SC4 Steve? Do you have it running and boosted yet?

Wasn't your original goal 300-350whp?

Lex, I think I am done looking at busted Xuz.. motors, cracked blocks, damaged rods, etc..... I got the info. I needed...

 

[stevechumo]

My SC is almost done (not running yet) and fuel enrichment is a must for sure. That's right. My goal is from 350 rwhp and up, which means from 400 bhp and up. So I'm a little stressed when I hear Mr. Lex scare the heck out of my ex...:yawn: