Hi guys (and girls), this is my first time starting a new thread here so bear with me; I'll try to be as concise as possible.

After lots of searching I never found anything mentioning my specific problem.

My car is an '08 Nismo. I am the second owner. I purchased it with 45k miles on it from my dad. It was bone stock.
I installed an Injen CAI and modded the exhaust with catless midpipes. Those are the only mods I had a chance to get to.

I have always been meticulous about oil/filter changes every 3-4k mi and letting it warm up all the way before hard driving but around 55k it started to chatter between 3k - 4500 RPM under light to moderate load. The sound was similar to the one heard briefly after cold starts before the oil reaches the lifters. Sounds kinda like a diesel engine. Anyway, it would become more pronounced as the engine temp rose, but would also go away almost entirely once in a while...like when I brought it to my mechanic. (I swear, it was doing it as I drove over to him but the noise stopped as soon as I picked him up. Drove him around for 10 min, no noise. Dropped him off and a minute or two later it was back. (I did turn around and go back but he'd left by then.))

I had 2 other Nissan techs listen to it & they could hear it clearly but neither of them would even venture a guess as to what it might be...they both just said that whatever it was "isn't good".

All along I suspected rod bearings but refused to believe it could be with such low miles & the care given by both owners. So I went ahead with my plans and took it to be tuned, figuring if it blows at least I'd finally know for sure what the problem was. I even signed a release of liability at the garage, stating I was aware of a potential problem and the guy was still reluctant to tune it but he eventually began and after 10 mins it was failing badly with knock sensors FINALLY throwing codes. He stopped before it threw a rod & I had it towed home. (Thought it might make it back but after a few blocks it was slapping so badly I knew it was just seconds away.) That was exactly 11 months ago.

So, I'm asking if anybody knows what may have caused this catastrophic failure so early on?

A bit of the car's history, in case it contains any clues:
Purchased new in MT where it spent it's first 10 years.
Only driven 4 months of each year.
Garaged every winter.
Transmission replaced under warranty @ approx. 7k mi.
Previous owner never ran premium fuel (said the dealership told him it wasn't really necessary).
Previous owner would occasionally rev it up high but mostly cruised around town in 5th or 6th to conserve fuel.
Oil was whatever the lube shop preferred to use, I think Pennzoil synthetic blend 5W40.
At 45k I bought it and had it professionally shipped to Cali.
Switched to Mobil1 10-30.

Mistakes I made:
After its first oil change under my ownership I lost track of miles & before I knew it I had put 5,500 miles on it.
Once, later on, I changed the oil but not the filter. Just one time!
Also, one time only, I accidentally revved it too high before it was totally warmed up...but there's a temp regulated limiter, no?

Other than that I always maintained it properly -- clean air filters, topped-off oil, fresh plugs & fluids.
I mean, I did drive it pretty hard, but only because I thought a car like that could handle it. When the chatter started it was immediate...was never there until one day it just started.

The only thing I've thought of to "blame" this on (if it wasn't something I did) is the fact that it never had a magnetic oil drain plug. It may sound insignificant but I cant believe they wouldn't just spend the extra $2.00 (if that) per vehicle for the added protection on a limited edition of their flagship model! Trans. has one. Diff has one. WTF? Maybe I just got a lemon & that wouldn't've helped at all, but i think that over time the oil take-up screen must've become partially blocked, unbeknownst to me, slowly causing more & more damage with every passing mile.

Thanks for taking the time to read this. I really appreciate any constructive input/theories/suggestions you guys may have so I can make sure it doesn't happen again once I've got my new engine.

 

Manual tranny going at 7k
Will these cars knock under WOT at higher rpm's with 87? If so, do enough of that and..well there you go

 

Sorry to hear about your HR. One bit of consolation is that your Z sounds like it received good care during it's 60K life, and it's doubtful any one thing caused the rod bearing failure. You don't mention what you're planning to do, but if you decide to do a rebuild (rather than just throwing a salvage motor in), you may get some answers. Whether you do it, or hire a dedicated shop, a careful examination may reveal what happened. Since you stopped before catastrophic failure, there should be clues to examine.

It's also not surprising that most techs were uncertain about the cause of the noise and vibration from your HR. After all, it's rare there are many Nissan failures with unmodded engines If any happen early in the warranty period, Nissan usually ships a new engine or shortblack, so techs never really get to see the inside of any engine anyway!

The only item I didn't read in your post is the lack of any UOA during this HR's lifespan. Even when you suspected a rod problem, a simple UOA may have detected additional bearing material in the oil before it got any worse. It's similar to a blood test for humans, as it's a non-invasive method to check on our overall health. Would it have changed the outcome? No, but you might have got an earlier start on a teardown.

 

First off ... please break your post into paragraphs - it's very difficult to read a post that is in one massive paragraph.

Next - dont over analyze this ... I spun a bearing at ~68k miles on the car and maybe 40k miles on a built block ... My caveat is that I drove the **** out of the car and I got every ounce of performance I could. I can isolate the failure to 3 or 4 things but in reality it failed ... doesnt matter, remove the engine and rebuild. Dont over think it, its a $9 part that failed ... Consider this is cost of ownership.

If you can rebuild the engine yourself (or with the help of a knowledgable mechanic) I would highly recommend it. It's very fulfilling, you will learn a bunch, and it's very gratifying. And you'll know that rebuilding an engine isnt the most difficult thing (as you may think it is).

 

I'm unclear. so have some questions...

- 11 months ago? So what's the car been doing since? You didn't fix it?

- The title says "rod bearing failure" but if it's not been torn down, how do you know the specific failure?

- What were the particular "knock" DTCs you referenced? I ask because knock sensors are "tuned" (by the specific type of piezo-e core used) to pick up specific types of knock. Most will NOT pick up rod knock. They are designed for the type of knock associated with detonation or pre-ignition. (This isn't definitive because in theory, it's possible to hear a mechanical knocking down inside the block; just not the usual find.) If it threw a P032X code, it usually means the sensor itself is faulty. And if it's bad, no handshake with ECM means "all systems PRESUMED normal" which could lead to detonation damage, which is usually head related, not block components.

- Did YOU continue to use low octane gas?

- You reference "previous owner". Are you referring to you dad (or did he buy it pre-owned)? Can you ask him any questions about its behavior before you took it over?

- Do you have a comparison point to tell whether the power was at the same power level as other HR-equipped Z cars? I ask this because if you were running 87, I'm going to say that it probably was not at the power level it should be. It is possible that the car has been running on a stepped down timing schedule due to the knock sensor doing its job and relaying info to the ECM which reacted by retarding timing.

I haven't heard or read of rod or crank bearing failure in the VQ other than from abuse (over rev, be it hard driving, by accident, or neglect). Not saying its "not possible" just stating it's an unlikely failure under normal operation.

This is far too complex to speculate definitively about the cause or actual damage. Need hands on for that.

 

Although I never heard any knocking or pinging I wasn't really around the car much for the first ten years. You've made a very valid point; one which I had not considered at all. (I only got as far as just knowing that running low octane fuel for that long could not be GOOD for it.) If it is the primary factor responsible for my situation then it's pretty effed up how it could all be traced back to some douche salesman telling my dad what he wanted to hear just to make a sale. (That the car doesn't REALLY need to run on premium.)
Although I'll never know for sure what went wrong this seems logical enough to give me some closure and move on without the constant, sinking feeling that no matter what I do it's bound to happen again.
THANK YOU

 

-- sorry... I think the formatting changed a little after I submitted the post but now I will be sure to clearly separate individual comments as the subject matter changes.

 

The car has been sitting in my driveway under its cover for 11 months. I`ve started it twice, just long enough to move it out of the way. I haven't made up my mind whether to rebuild or replace with a built one.

I lost an engine (VW G60) to rod bearing failure years ago and had it rebuilt so I know that’s what it was. The chatter coming from my HR was exactly the same sound & progressively wore in the same fashion which leaves me 95% sure it's rod bearings.

I only ever ran premium, frequently with Techron & sometimes with Madditive Octanium (just a few ounces into a full tank).

My dad bought it new & I bought it from him. He didn't notice anything that would raise a red flag -- never had problems with it except the tranny early on. But he's not by any means an enthusiast & was never tuned in to its behavior on a daily basis. (He once changed the oil in his Saturn & forgot to put the filler cap back on then proceeded to drive it for 7 hours on the freeway... can you say "rings & valves"?) I'm not suggesting that anything of that nature occurred with the Z -- had it, he would have told me long before I bought it.

 

You're right, I should've had the oil analyzed as soon as I noticed anything unusual. I changed the oil right before pushing it too hard on the dyno. That oil is still in the crank case....guess it might be worth sending in a sample.

 

This I do not know...wasn't told, didn't ask...I was a bit distracted in that moment.

I will pull all codes sometime later today & record them here.

While it was on the dyno he did 2 full pulls and then came out and told me that it was producing a fraction of the power it should, IIRC something like 160 hp. (Premium fuel only.) I believe he did say that it was most likely trying to protect itself thru timing ret.

 

Confirms my thought that the knock sensor was probably functioning (until it didn't).

HR pulls much more strongly than the DE (obviously in the upper range). Unfortunately, if the motor was detonating, there could also be long term damage to the heads, e.g. bent valve, or other valvetrain issues.

Another thing I've run across that sounds like a rod knock is a bad harmonic balancer. You might want to check that before pulling the motor/rebuilding. Good luck!

 

Wow, I read this and just think to myself...imagine not putting premium fuel in a car that has a sticker that says premium unleaded only. Not to be a dick but man that is easy info to find, I won't trust anyone over the manufacturer lol.

 

Ok, I forgot about the battery being disconnected so those codes are long gone. I could start it up & generate some fresh ones but I disconnected some fuel lines in order to drain the gas tank and have to take care of that first. Not sure that this would actually be of much use though in terms of telling me something I don't already know; the thing is so loose and slapping so loudly it could throw a rod at any time.

As much as I'd like to rebuild it myself (probably will eventually) I'm pretty short on free time & space at the moment.

Does anybody recommend a particular source for built engines? Not just reman stock or crate, but someone who just rebuilds them to higher specs and always has one ready to ship?

Im beginning to think this is a totally insane thing to request because I haven't come across anyone doing it & I've been searching, off and on, for almost a year. I found one guy, actually . He was a total dick & didn't want to waste his time answering my questions or listening to me answering his.

I have a reasonable budget to work with, but don't want to spend $10K...

Thanks again!

 

Dynosty or Soho, but if you want a complete engine it's gonna cost you. I believe Soho starts at 12k.

 

Yeah, I was visiting my dad the second summer he'd had the car and the transmission was humming and whirring in neutral & resisting 2nd. He said he'd noticed it and I was like: "Dad. Its a brand new car. TAKE IT IN."
So he did & they diagnosed throwout bearing & synchro. Ordered a whole new unit & a week later it was ready to go.

 

DAMN! Are they epic enough to justify spending that much? Maybe I should follow advice given here and rebuild my own...not that I could produce what these guys do but...well, just DAMN!

 

It's going to be difficult to find any rebuilding service that has a high-performance HR ready to go. After all, it's an engine that was only produced by Nissan for a limited time, plus each customer will want different options (pistons, bearings, hardware, etc.). If you're looking for something more affordable, consider having a local shop do the top end headwork, and purchasing a remanmed shortblock. Don't get too ambitious or it'll cost you far more than your sub-$10K budget.

 

Are they epic enough? Probably, Google Nismobae lol. They have a rig to run engines prior to sending them out and a exclusive build process that eliminates head lift, so I'd say Soho is pretty serious. But to be honest you could just get a built short block and have a shop swap everything over. IDK if anyone asked about power goals but if you aren't looking to push a bunch of power the HR is very competent in stock form, you could just swap in a used one or get a new one from Nissan, that would be under 10k.

 

Save Money and Stop Buying Premium Gasoline

Modern Engines Make Allowances for Lower Octane

by Jason Kavanagh
October 19th, 2018

A quick way to save 20 to 40 or more cents per gallon at the gas station is to stop pumping premium gasoline and switch to regular grade. But how will you know if the switch is safe or if it will damage the engine in your vehicle?

The key for drivers is to know whether premium gas is merely recommendedfor their car or if it's required. In today's automobiles, advances in engine technology mean that even if the owner's manual recommends premium gasoline, the car will typically run on regular without issue and won't damage the engine in any way. The car's performance might suffer only slightly: It might be a half-second slower from 0 to 60 mph, for instance. But the average driver isn't likely to notice this drop-off.

Drivers used to buy a tank of premium gas every once in a while to clean their engines. Years ago, premium gas contained more detergents and other additives to stop carbon deposits. But experts say that now, because of government regulations aimed at cutting emissions, most major brands of gasoline have plenty of additives in all grades to both protect engines and cut pollution.

Edmunds has compiled two lists: Premium Recommended and Premium Required for vehicles from the 2012 to 2018 model years, with some 2019 models included. If your vehicle is on the Recommended list, you can try switching to regular unleaded gas. If your car is on the Required list, then you need to run premium gas. You can confirm the information on these lists by checking your owner's manual.

Smarter Engines Protect Themselves

If you're still in doubt about switching to a lower-octane fuel, here's a more in-depth explanation of why the change is unlikely to hurt your car:

First of all, premium gas has a higher octane rating, an important factor in helping prevent engine knock or "pinging." Depending on where you live, this premium-grade fuel could be 90 octane, 91 octane, or even 94 octane.

That's one reason premium costs more. To increase the octane rating and reduce knock, refineries use a more elaborate process that blends an expensive substance called alkylate into the fuel.

What is engine knock? After vaporized fuel mixes with air and fills the combustion chamber, rising pistons compress it. The spark plug then fires, initiating the combustion process. But combustion doesn't happen instantaneously. It takes some time for the flame kernel to develop, grow and then burn the entire contents of the fuel-air mixture in the cylinders. There's a critical period in the middle of this process when the mixture in the unburned region is being heated by the neighboring burned gas while being compressed by the rising piston.

This one-two punch can cause the mixture in the unburned region to self-combust rapidly in an uncontrolled fashion. That's the knock, which hurts power and can damage the engine. Simply put, high-octane gasoline can be compressed and heated to a greater degree without self-igniting. That's why high-performance engines use premium fuel.

In the old days, engines could not deal with fuels of varying octane ratings. Using the wrong fuel would make the engine knock and possibly damage internal engine components. But today, engine control systems can compensate for low octane by adjusting ignition timing to avoid knocking. This sophisticated electronic capability effectively tunes engines on the fly and gives drivers more flexibility in the grade of fuel that they can use safely.

Compared to premium gas, lower-octane fuels don't allow the engine to run as much ignition advance during situations calling for rapid acceleration. More ignition advance causes spark plugs to fire sooner, which (within limits) allows the engine to make more power — and accelerate more quickly — under these conditions. Since the engine doesn't make quite as much power with low-octane fuels, this translates into slower acceleration in cars for which premium fuel is recommended. The performance loss is especially noticeable in turbocharged gasoline engines, which have become increasingly popular in recent years.

The performance loss, however, is something you will only notice if you have a heavy foot and accelerate rapidly from a dead stop or when you change lanes at highway speeds. But if you accelerate moderately, the loss of power may not be noticeable whether you use premium or regular-grade fuel.

When Premium Can Be a Money-Saver

Edmunds has noted, however, at least one case in which a car with a small turbocharged engine returned better fuel economy when running on premium. The owner's manual of the car in question, a 2011 Chevrolet Cruze LTZ, called for regular unleaded gasoline. Yet in a specific test, we noticed that we got better fuel economy, and ultimately saved a bit of money, using premium fuel. We conducted the testing in the scorching Death Valley, which might have influenced the outcome.

Since then, small turbocharged engines have become increasingly common in new cars. In 2008, three years before our test, turbocharged engines were standard on only 10 percent of vehicles. In 2018, it's 45 percent of vehicles.

There's no guarantee that all of the overachieving engines will benefit from higher octane as the Cruze did in our 2011 test. You can try this yourself to see if you can save money by using premium fuel.

Monitor your fuel economy and performance over at least two tanks of premium fuel. Record the trip mileage, gallons used, fuel price and octane rating in a notebook or with an app such as Road Trip or Fuelly. If your car has an onboard fuel economy meter, make sure you reset it when filling up. Then, fill up on the same number of tanks of regular gasoline and record all the same data. Finally, compare the results. You're looking for a drop-off in fuel economy or a sense that the car is slower or hesitant under strong acceleration.
That's the drill for a premium-recommended car. You can stay with premium or step down to regular unleaded if you prefer.

It's a different story for a car whose engine requires premium fuel. The car will run on regular fuel in a pinch, but you shouldn't make a habit of it. The fuel's lower octane can result in elevated exhaust-gas temperatures and possible knocking, both of which can adversely affect the engine's health in the long run. Running regular-grade fuel in a car that requires premium might sound like an easy way to shave a car's operating costs, but the short-term savings won't come close to offsetting the cost of repairs to a damaged engine.

For those driving premium-recommended cars, however, it's just a matter of driving moderately and avoiding acceleration with a wide-open throttle. Do that and you might never feel the difference between using premium and regular-grade gasoline. And neither will your car.

 

Understood. Thanks. The more I read/think about this the more "ambitious" I get!

I need to keep reminding myself of what an impressive engine the HR is, even in stock form, because my experience (up until 3 days ago when this thread answered my nagging question) had left me thinking that it was somehow fundamentally flawed therefore inevitably prone to failure.

It may take a while to wash away the bitter taste, as this was a particularly devastating loss to me (& I own an RX-8, so you'd think that having to replace an engine would be no biggie). But this car is special.