How common is that issue?

 

hard to tell. Left unchecked, it might go for months, maybe even over a year before it gets the point where the engine pops. I'd guess that the the first symptom most owners would notice would be the hole in the engine block. But there will probably be oil consumption issues before that, where the warped rods are allowing oil to enter the combustion chamber. Maybe thicker black smoke would be an indicator. Warped rods will generate lower compression, so a compression check will likely indicate cyl's 1 and 4 down at least 10-20psi. I'd bet in a lot of cases, the excess heat generated due to the loss of oil is probably the actual cause for the failure, not what warping.

The only reason we have these pics is because a few lucky people decided to do a rebuild at just the right time and found the rods like this before everything went to hell. How long were they out of shape? who knows. Are my rods like this right now? who knows That's why I'm building my bottom end before I do any more power mods, period.

 

How much power was the person running on the Pictured rods.. any history on the car?

 

i know the top one was on a stock turbo with just an fmic, dp, and catbck on pump gas. no idea about the tune or power levels. Owner brought it to a tuner because it started sounding funny. Tuner thought it was rod knock. Go figure

dunno much about the 2nd. But i've seen a handful of other pics where the warping isn't as bad, but still very noticeable.

edit: found some info on the 2nd - guy bought a used X GSR with with intake, catback, HFC, and DP. Went to get it check out by Forged Performance. Baseline put down 288whp. All those mods and stock tune =/ They found some minor boost leaks. Turns out the rods were bend, cyl walls were scored, and turbo was destroyed. He ended up doing a full rebuild with a BBX, manley I-beam rods & pistons, full AMS breathing package, tomei cams, e85, etc. Put down 502whp after it was all said and done.

 

Well from the sounds of the accounts of most of the failures, it just seems this motor doesn't seem to like to be "lugged". But I find it strange the first thing to give is the rod. I would expect the crankshaft warping, or piston slap, bearings worn out, etc. But for the rods to bend and/or snap, and usually just in one or two cylinders is strange to me. But the stock map should be able to compensate for lugging. From what I've read so far, it seems like the motor doesn't lug at all, it just...blows. My experience tells me, lugging the motor with low RPM/high load will only blow the motor if you lug the motor, and you feel the motor struggling. I mean feel it! The motor rocks and the car shudders. There has to be something wrong with these rods.

I apply throttle at sub50MPH speeds in 5th/6th gear all the time. I don't feel any struggle by the motor, and power delivery is smooth throughout the RPM band. The thought this simple action could leave me without a motor is ridiculous.

 

It is these kind of threads that make me want to say F it and not mod any further.

Just stay with the few bolt-ons I have and be happy.

Considering if the motor/head gets destroyed you're looking at easily $7k for a built shortblock, stock head, and installation, and I really don't wanna have nearly $20k tied up into this car that I'll never get back.

Not to mention those bent rods are just sketchy, good thing I have ZERO oil consumption, but this still sketches me out. This is the reason why I traded in my STI, is to have a strong motor.

 

You guys have me scared to death to drive for fuel economy anymore. Guess I'll have to drive ***** to the walls anymore and say screw fuel economy. Guess that's the way the Evo is supposed to be driven anyway. Just a thought, but is this a rare occurrence? I thought this motor was pretty much bullet proof or is this a misconception?

 

I would hardly consider these engines bullet proof in anyway.

Rods giving up at less than 400wtq does not impress me.

 

One of the reasons I bought my X over an STI was because I thought I did my research and there were less motor problems with the X than the STI. Guess I missed something. The other reason is the X handles much better than the STI. The third was the X is easier to add bolt on mods and get results. The fourth was looks (personal preference). I'm not liking what I'm reading in this thread.

 

Not to knock on the 4B11 but this is exactly why they need to bring back the strong 4G63, I remember a buch of us were making great power some over 500 with no issues

 

 

We need more info from the OP about what happened when the motor blew up. This is concerning to me and many of us as to what happened. I don’t want to experience this.

I agree with the comments that 29psi is to much for a stock turbo, but that is irrelevant when driving in 5th gear cruising at 45-50mph. Even a partial throttle doesn’t bring the boost to 29psi. The only way to get full boost is WOT.

When I had my car tuned, the tuner specifically told me to never to go WOT if I’m in 5th gear at 2k rmps. He told me to downshift if I want to accelerate if I’m in 5th at low rpm.

Anyhow, we need more info about the tune and any other issues that could have caused this to happen.

 

Sorry to heard bro...
that is crazy if u dont mind to share where did u tune ur car.. so other member can avoid this kind of issues..
hope you get her back to the road...

 

I was doing a'bit of research about the matter and found this, i don't know how relevant this is to op or anybody else?

By up-shifting at low rpm, you’re asking your motor to deliver power at its point of lowest “mechanical advantage”, which means you’re forcing the pistons, wrist pins, con-rods, crank, and journal bearings to accept the force of a large explosion pushing against a relatively unmovable object. Sketch out the kinematics and you’ll see what I mean. Yeah, I know the titanium con-rods have better fracture toughness characteristics than your standard NASCAR-issue steel con-rods, but the wrist pins and crank bearings are still susceptible to shear and just plain getting the crap skwarshed out of em. And the aluminum pistons are getting a hot fire on their face with no way to get away from it.

Continually running the motor at low rpm forces it to operate at less than desirable volumetric efficiency, which means that there’s not enough breeze flowing through the motor to blow out all that heat and combustion by-product adequately. Resultant to that is that the motor doesn’t achieve a good internal operating temperature, which allows the aforementioned gases to cool, and condense into gunk which will then apply itself to your plugs, pistons, et c.

Due to valve overlap, along with the stated low volumetric efficiency, some of those gunk-producing gases can emigrate out of the combustion chamber and blow back and settle onto the valve seats, or maybe even all the way around the valve, to collect on the stems and in the seals. That may not contribute directly to a loud valve tick, but it will likely eventually contribute to worn seals/seats. Then again, gunk buildup in the valve seat area would preclude full valve closure, effectively increasing the gap between cam & valve, making a louder tick.

Further downstream, your catalytic converter has to purify this flow, and, because the cat-con isn't hot enough, the same gunk-laden gases cool and condense in there, further reducing efficiency of the breezes flowing through your motor.

Herr Bosch points out, however, that a 4-stroke engine has “very good volumetric efficiency over the entire engine-speed range, low sensitivity to pressure losses in exhaust system, as well as relatively good control of the charging-efficiency curve through selection of appropriate valve timing and intake system designs.” What that means for us is that we probably don’t have to worry about gunked-up motors as much as in the old days, because Honda-san gave us some good electronics (and VTEC at the upper end of the rpm spectrum), to account for most of the undesirable low-efficiency effects. However, there’s still that nagging kinematics problem that can be cured only by changing lifestyle habits.

Give your motor a break. Shift at 4k, 5k…any additional induced wear is less of a concern than shearing wrist pins, burning pistons, fouling plugs, or squashing the guts out of your crank bearings. And you don’t have to spend a half-hour at high rev’s while you’re shifting. Make a moderately spirited acceleration, shift, have a little fun, listen to the motor sing, and then get into cruise mode. It’s a Honda!

found on nsxprime.com

 

whut...?

i've been cruising at 5th gear at ~40mph locally for 42k miles now. if 5th gear is not used for cruising then it must be there just to annoy you keyword here is cruise - if i need to pick up speed, i always downshift. i also warm up my car from a cold start religiously.

judging by the graph and the circumstances i'm sure it's a problem built up over time. frankly i've never heard of anyone tuning the stock turbo to 29psi.