joenismo

Well I hate to admit it but add me to the list of FI casulties. I just got done boosting through second gear shifted to third and drove normally 3000 rpms when I heard a soft clicking sound. I was trying to listen carefully to it when boom. The engine was still running but I turned it off very quickley and pulled to the side of the road. Antifreeze was coming out from the right side. I towed it back to my shop and started to tear it down. I first pulled #5's spark plug, nothing wrong at all, no signs of detonation or running lean, or slivers of metal. There is a small hole in the side of the block in the number 5 cylinder. The rod actually sheared in half. Bottom half still attatched to the crank, top half in the upper part of the cylinder. I see no signs of damage to the top of the piston, I am hoping it didn't slam into the head. At this point I don't think the whole thing is a total loss. Now the question is why. I always run 94 octane at 6.6 lbs of boost. I did initialize my e-manage and have used a table richer than GQ's. I do not have any ignition retard although with 94 octane and an A/F ratio of between 10-11.5 I didn't feel I needed it. Was my engine definately detonating, I am sure there would have been tell tale signs on the sparkplug. Everyone knows our rods are the wink link, I guess I know now how weak. I have run my car much harder in the past than one gear through boost, especially second, I have many passes at the track.

SQUILL

That sucks!!!! how many miles do you have on the TT motor??

So you think no tuning issues just weak rod??? When will you have the motor apart? Keep us updated!!

350Now

That sucks at 6.6 lbs and the rods broke. Keep us updated of what you find and what could be the possible cause of the rods breaking.

joenismo

I am guessing I had around 1500 miles since the TT. I am not ruling out a possible tuning issue, but I do feel I tried to take most of all the preventive measures, wideband O2, fuel pump, octane, ect. for this to not happen. I will post pics when I get the engine out and apart.

Apexi350z

iTrader: (3)

Was it hot when this happened? what was the outside temperature? just wondering..

slay2k

Okay, let me ask you a few things.

1. Do you have the Greddy TT ?
2. Did you floor the gas while in 2nd gear, somewhere around 4000 RPMS ?

Because if you did, your actual boost (for a second or so) would go as high as 8-9psi. Trust me, mine spikes like that when I floor it in 2nd gear... but only very briefly. I haven't had any problems with my engine though, I also run 94 octane but my boost is at the stock 5.8.

narkotic

iTrader: (3)

Maybe someday you guys will learn that pulling timing is a good idea, regardless of fuel in your area and PSI boosted. Our motors are VERY sensative. good luck man

joenismo

It was about 65 degrees outside, yes I floored it in second but I have my gain set at 6 and I know I am not spiking to 8 or 9 lbs. Maybe low 7 but just for a second and I know at 4000 (or when it may spike) my A/F is at 10 and timing should not be that far advanced at that rpm. Yes I do have the Greddy TT, and I agree that timing should be taken out, I wish it was as easy with the split second box of the Vortech.

zimbo

iTrader: (4)

This is disheartening news indeed and makes me think it's time to start pricing rods/pistons/etc.

--Steve

SQUILL

joenismo isint it interesting than it was cylinder #5 .....i not saying it is tuning related either just yet as you havent seen inside the motor but once again # 5 is at fault.

Every F/I motor #5 or # 6 like every last one that ive heard of.

Too many motors #5 and #6 causing the destruction ..you know if your wideband is reading 11 at redline its still possible that #5 and 6 were much leaner as your wideband can only measure a bank of cylinders not each cylinder individually ...as they have a tendency to run leaner maybe this is what happened once again ...when u get the motor apart let us know what it looks like in there and post some pics if you can.

Might be the factory plenum again ...but who knows right now?

phunk

iTrader: (21)

That ****in sucks, and it doesnt really sound like you have done anything wrong.

Let me tell you guys... I may have only had my Greddy TT running for about 2 weeks... but I **** you not I just hit 2000 miles today on it. You can ask anyone, I beat the living **** out of this car. All I do is just take customers for rides, practice sliding around in it in industrial parks in the middle of the night, etc etc. I pound on this car the entire time im driving it.

My boost does not ever spike above 6.0 psi when I floor it in any gear. The only time it spikes is when I am letting on/off throttle in first or 2nd trying to get traction. Even than, the most it ever did hit ONCE was 7.3 psi.

I am running stock timing. I never turned up the boost cause I am paranoid about the motor.

However, I have ONLY run the car 100 octane gas, just as a precaution.

Now, typically rod failure does not happen from tuning. But with a crappy enough rod, anything is possible. Apparently these rods are plain junk. Almost any motor will melt/crack a piston ring land before throwing a rod from aggressive tuning. If the pistons can take it, there is no excuse for the rod not to be able to take it.

WTF was Nissan thinking with these cheap *** rods. I would have rather paid $500 more for the car and had it come with some forged rods like every other performance import car has.

The world I come from, MR2 Turbos, the stock rods have seen over 500rwhp in a few cases (from just 4 rods), and over 600whp when shot peened in one case... and in ANY case I have NEVER heard of the MR2 motor breaking a rod.

I got my ignition harness, and I was gonna pull out some timing and jack up the boost to maybe 9psi and continue with my 100 octane only trend, but now I am thinking twice... I will have my sleeved block built very soon now, and I would rather keep this block in one piece so I can use it as a core for a customer who wants a build up without tearing their car apart before a new motor is ready.

Maybe I will just hold off on the more boost thing until I get the FCON installed and the new motor... which sucks I just got my drag radials and wanted to try the track at 9psi and see if I could get some low low 12's or maybe even an 11 (doubtful).

Sorry to hear about your motor man. Very crappy situation.

GurgenPB

iTrader: (2)

This sucks. That's too bad about the motor. This makes me think twice about running the stock plenum with FI. I will be going to the Crawford plenum soon, as it's the #5 o r#6 cylinder that goes almost every time.

G

phunk

iTrader: (21)

i dont know if i would blame the plenum. In most cars there is usually 1 or 2 cylinders that are always the first to go. Just due to the design and layout, not all cylinders will be at the same temperature, or harmonics could possibly differ through the engine, it could be a lot of things. I would have my doubts its related to the plenum... however I definatly would not say that its for sure NOT the plenum... I just dont know if I would point a finger so quickly.

Elitemotion

iTrader: (2)

Think it might have lots of things to releate to eachother, but I would think the main part would have to do with the plenum than off from that the rest of your points..

only way to find out is to flip the plenum and give #5 n 6 more air..

good luck rebuilding the car though.. it will be better

Sharif@Forged

iTrader: (92)

Joe, I am really sorry to hear about this. Definately a first rod failure at low boost condition. I have posted before that even at stock boost, some of the Greddy installations were pinging here in my area. My car, Wild350Z's and even some stock 350Z's tend to ping...especially at lower RPM...between 3000-4500rpm. Sounds like this is the range where your motor blew. I certainly wouldnt blame the tuning, since you were running pretty rich, but not rich enough, in my opinion, for rich detonation. 6.5psi is a bit aggressive without ignition timing retard, and you definately heard pinging, so that was the culprit. I'm pulling about 6-7 degress of timing out of the topend, and running 91 octane gas at 9psi, I havent heard a ping yet. Since I'm moving to Charlotte, I'll be running the good 93-94 octane stuff, so we should be OK.

I am really sorry for you man...dificult situation, but we ALL really appreciate you sharing your story and insights as the tale unfolds.

How long and loud was the pinging before it blew? These rods are definately wimpy, so I know its not necessarily the boost level that cause the failure. But ANY trace of pinging can, I guess, destory the rods very quickly....wow....crappy rods man. Even with ZRAYGO'S overboost blow-up, he actually blew the head gasket and damage the piston/rings.....the rod was intact. This is a very interesting development.

One last thing, it will be really interesting to see the condition of the rods, bolts and pistons when you break the motor down. I'm interested to see were the rod snapped, and if the rods bolts themselves were at fault...or whatever else. Could be some good learning here. Many have speculated that the weak part of the rod is actually the rod bolts, not the rod itself...although it looks pretty skinny to me.

Can you have the engine warrantied at a mod friendly dealer in your area? Not sure how they are up there.....if you are successful, you wont be the first person to get an F/I engine swapped up gratis under warranty.

If you need anything..lemme know.

myz8a4re

iTrader: (2)

terribly sorry, im posting just to hear more about the rod failure. again, sorry to hear!

-justin

Sharif@Forged

iTrader: (92)

Joe, I have been thinking about this all day since I read the post the first time.

Two other things come to mind.

1) You mentioned you installed the Walbro 255, no FPR, which is the setup I have. You also mentioned you are using a map "richer than mine". But mine is set for 9psi and the Walbro...I think I also posted a 7psi without the Walbro. So if you used those maps, and your pump, and you only ran 6.6psi, you were likely running dangerously rich, which can cause pinging...just as a overly lean condition can as well. Also, since you werent using the ignition retard map, that could have contributed as well. Usually, you see rich detonation in the sub 10.5 range, and usually below 10.0. Did you get a good look at your A/F's prior to this incident?

2) The second thing thing that came to mind is that maybe...just maybe...you had a defective or exceptionally structually weak version of the VQ motor. Nissan makes thousands of motors every day, and it would not be uncommon for there to be some poorly put together versions. Even though mass produced, we know that no two engines are identical, and no two ECU's are really identical in every way. These cars and ECU's seem to have a life of their own sometimes. I am just trying to think of any alternative, yet plausible reasons for this catestrophic failure. It is so bizzare, given only 6.6psi of boost....I still can't believe the rod just snapped, even if some detonation was present. Catestrophic engine failure usually happens under much more extreme conditions that this....

Let the post-mortum begin!

AmyCroft

iTrader: (3)

joenismo

Let me first clarify, I never heard any pinging, the clicking sound I heard at 3000rpms was under no throttle at all. I believe the rod had already snapped and the clicking sound I heard was the bottom half of the rod slapping the inside of the cylinder until it slapped it enough to put a hole through it. I definately do not think I was not too rich, just slightly enough to be on the (what I thought was) the safe side. I can see the rod still attatched to the crank with the bolts so I do not think the rod bolts are the culprit. I agree with the plenum, when I get it back together I will not be using the stock plenum.

joenismo

The only other odd thing that I can add is when I did make boosted pulls and then shifted(letting the throttle off when shifting) I often heard a pop once I let off the throttle to shift. This is without getting near the rpm limiter, usually around 6500rpms. I did hear this after making the final pull, in second shifting to third. I then continued to just cruise along at 3000 rpms this is when I started to hear the clicking sound. Has anyone else every heard a pop that I am describing?