This is on my buds vette. Some history, we had a thread going about this recently.

98 vette, a4, 80k miles. stock save for a halltech. ran a tnt 75 shot, then recently 100 shot. Never dyno'ed above 10.5:1 on the juice. Doesn't even have a bottle warmer.

2 weeks ago, we have a local shop install, patriot 5.7 stage ii milled heads, 224 comp cam, pulley, ls6 intake, and kook headers.

We started it up on dyno, and a/f ratio was a solid 18:1, which if I'm not mistaken is the highest a wideband will read, so it was probably higher. I pointed this out to the shop owner/dyno operator, and he said it takes a while for the O2 sensor to warm up. He then proceeds to dyno the car. It was 18:1 across the board. Made 375 rwhp. We then notice the #8 primary is cherry red. He shuts it down, we put a MAFT on it, and run it again. It is still lean, although not as bad. Made 372. Car acting strange with regards to charging, etc. The guy who owns the shop forgot to hook up a wire near starter, which we did not know until later in the week. He hooks the wire up and it is fine. We redyno, it makes a disappointing 362, with a rock solid af ratio of 12.9-13.0.

We did a leakdown/compression test, seemed fine.

One week later, my bud goes to track. He makes 3 runs today, on the 3rd run, the blockoff plate on the header pops off (near #6 and #8). He fixes it, but notices more noise from engine. Proceeds to drive it home, and engine locks and parts on road. Passenger side of motor is covered in oil.

My initial thoughts are, the 18:1 WOT/dyno run fooked a piston/pistons, and one let go at track. If we pull the heads, I'd be willing to be the #8 piston is trashed.

What can we do to resolve this with the shop owner? My bud paid $1500 in labor to have the work done. In my opinion, and assuming its a piston that died, is that it was his fault. I pointed out it was 18:1 before he started the run, and he dyno'ed anyway.

Chime in. What can he expect? What 'legal' means does he have?

 

I do not think he has much legal recourse. Unless it was specifically something the shop did to make the engine die. Installing aftermarket parts would not be enough reason IMO. The part that will hurt your friends case will be that he was present during the dyno and never stopped them when he knew the AFR was at 18:1, if indeed that is what caused the failure. However if there is solid evidence that the install was not done to spec and things were left off (like wires) and those things were the cause of the failure then he may have a case.

 

My friend was at the other end of the shop and did not know it was an a/f of 18:1. I told them myself it wasn't right. And they did forget to hook up a wire to the starter, which evidently caused the computer to go wacky and cause it to run VERY lean.

 

Definately should not have been run wide open with a AF ratio like that. The shop should have pulled the plug and sought the problem before dynotuning. What shop was it?

 

I'm not sure I want to say until everything is resolved. I want to give them a chance to resolve it before their name is dragged through mud.

 

Wonder if the injector on that cylinder had a problem. Ran lean and burnt a hole in the piston?

Won't know till ya pull it apart.

But anyway, that shop is a bunch of jerkoffs. That's why I do my own work.

Dope

 

Can someone host the jpg image of the 18:1 dyno run? I'd like to see some comments on it once it is seen by all.

 

I figured that dyno run fubard the motor. Hopefully they can work something out!

 

yah man if i saw a dyno operator even consider dyno'ing a car before closed loop sweep i'd knock his *** out of the car and do it myself (and i do drive the on dyno's now). If you see it go red, on the screen, let off, real simple.

This is dynojet 101 training they give the folks last time i check.

wait for closed loop temps so you don't wideband a cold-enrichment mode which is absolutely useless for tuning.. since most cars add fuel WHEN COLD start.

Sounds like a moron dyno operator. Did you sign the sheet? Most dyno folks have a disclaimer that says if your motor comes apart on the dyno tough cookie.

i hope not.

Then you might get the place on negligence, common man knows to let off a dyno when the bar goes to red or doesn't ever reach stoichmetric..

 

Before you even take the "legal" route. Call the shop tell them what happened mention you brought up the 18:1 A/F ratio to the dyno operator who ignored you. If they dont give you a acceptable resolution then I would seek legal recourse. Do you have the dyno sheet showing the A/F ratio?

 

Well not to start a flame war but a few things here....

1. Car has 80-90k miles
2. 98 Stock bottom end LS1 - Stock crank, rods, bearings, bolts, pistons
3. Just saw dyno graph not solid 18.1 A/F 16.3 (yes lean) rising when the run was aborted early with no audible detonation
(may not look like it at first but the rpm's read wrong, after car electrical was fixed and redynoed that graph goes to 7500rpm way over the limiter so the RPM was reading high through the pickup)
4. ALL TUNING of this car was done the poster (Mr. Fell) except the MAF table was changed back to stock since he altered the table for an 85mm MAF but this had to be changed since the MAF was a SLP recalibrated unit so the table adjustments were screwing the car up.
5. Plugs were checked, leakdown was done all seemed ok
6. Car drove fine for a week or two, don't know if he ran it hard on the street
7. Made two NA passes all seemed fine
8. Made a Nitrous pass, and blew off the air blockoff plate, made a new plate and started the car, had a non rpm dependant tick/knock
9. Drove car home and on the way blew the motor, parts/pices on groung - oil everywhere
10. closer inspection plugs look fine, little oil on #6 plug
11. Looked at motor, large hole in side of block where #6 rod went through the block

This is what I know to be the chain of events but may be incomplete/inaccurate


My thoughts/feelings/opinions...

When you start to modify an engine you take a risk at breaking something
When you put on heads and cam you take a risk at breaking something
When you race your car you take a risk at breaking something
When you spray 100 shot you take a risk at breaking something
When you spray 100 shot, with heads, cam and higher compression you take a big risk at breaking something

Yes it sucks to blow an engine but its part of racing especialy, a highly modified, sprayed, stock bottom end 90k mile motor


Could the dyno have hurt it? Maybe
Could an injector go bad at the top end with nitrous? Maybe...
Could there have been a fuel pressure problem? Maybe...
Could the rod bearing or bolts just not able to handle the stess anymore? Maybe...
Could it have been a bad tune with Edit? Maybe...


We will all just have to wait and see after tearing into the motor, and when this post was made no one had talked to the shop yet.


PS. Maybe it didn't make the numbers beacuse the heads you ordered wern't the right ones, the ones originaly wanted and were also some of the worst looking heads I've seen to date interms of combustion chaber casting flash. Don't get me wrong the cnc work was excelent but they could have used some clean up in the chambers.

PSS. (Edit: Deleted)

 

http://12.221.222.200:6580/lean.jpg

I was under the impression that extreme lean conditions are very detromental to engine longevity, more so than running 300 rwhp occasionally with lots of highway miles, and a few 75 shots on a stock rwhp motor.

 

It's hard to say what caused what.

If you pop the heads off and see #8 missing most of the piston crown then it's possible that is the cause.

 

Who would even dyno showing 18:1 AFR across the board...the most I have ever seen usually is at 14.7 at the beginning of the run...I never have seen one at 18 and stay at 18...that doesn't sound right at all.

 

I wanted to point out that it did richen up at one point in run. 16.3:1 afr

 

Greg,
Just wanted to let you know,if anything happened to the heads during the 18.1 dyno runs,I will fix this for you.Let me know how I can help.

 

Christ, there's no telling how lean it actually got. That power curve looks like *** too. Hate to see that happen to anybody. You have to do more than just burn the piston up to throw a rod out the side of the block, don't you?

 

Hmm, sounds to me like there had to be major detonation and it should have been audiable. The self ignition point for most street gasoline grades is right around 14.7:1 in a perfect world. It actually will reside around 13:1 +- or somewhere in there. If that wideband is even remotely accurate the detonation just pounded the rods so hard it doesn't surprise me that a rod failed and let go. Did the bolts break or the rod itself? If it was the rod itself then I would suspect detonation for sure. If it was the bolts then your guess is as good as mine being detonation is gonna pound the rods more than the bolts. Hope it all works out for the best man.

 

18:1 that could of easily caused a lot of rod damage that was not detected by leak down testing. I will have to give credit to TVWilkes for offering to help you out, but the dyno shop I have other thoughts on.