ill find pictures on my pistons i blew a complete hole in the side and deformed, i tell you one night of just a little off tune

 

It is not always a retuen style system. Some of the teams run dual pumps with duel regs, AFAIK

My number 4 was COOKED, but my other 3 were fine.

 

Mine blew as well. It was after I sold it though. The guy didnt have it much more than 2 or 3 weeks and 3 of the 4 pistons fried. It had robs tune as well.

 

I have seen this happen to a lot of peoples tune, all started from scratch, so I personally am ruling out the tunes.

 

i ruled out the tunes a long time ago man, its ******* fuel, we need a better delivery set-up whether it be returnless or mroe pressure

 

Pics would be nice. Do you still have the pistons. Comparisons, with some of the other pistons, of the crown, the damaged area and underneath would be interesting. Looking at the opposite side of the damaged face for visual signs of cracking could also be telling.

Pierre

I'm curious to find out more about this. Is it a skip like 1 cylinder misfireing or does it shut off completely for some length of time? Does timing advance make a difference also? Octane? Anything in the log of interest?

Pierre

 

listening.....

 

You know what, that is quite peculour, mine blew at about 147-148 mph which is 6700-6800 rpm in 4th gear.

 

mine just popped the dipstick everytime i got on it then started smoking then got worst but it always ran fine it just got loud and smokey. #4 was fried #1 and #3 were craked

 

that is about where mine blew on the dyno 4th gear pull at around 6500 give or take

 

Just got a phone call from the dealership .......

06 Cobalt SS/SC 18,300 (ish) miles

Toasted cylinder walls ....... STOCK!! No tune, no aftermarket parts ... had a spirited freeway drive into work on the freeway a couple days ago ... and was rattling when I got to work ... wasn't even pushing the car !!

New engine on the way under warranty!

 

WOW!!

 

what kind of rattling noise?

 

Hmmm, I'm not a very descriptive person but I'll try my best ...

To me it sounded like it was on the top end, somewhere in the valvetrain ... never would quiet down when revved but OBVIOUS at idle .... never lost any power it seemed, just was noisy .. Almost like it was ran out of oil or something (which it WAS NOT!)

If it was a SBC, I would have said it it was loose rockers, bent valves etc ... but on this thing, who knows

I DO know, they didn't even tear it apart ... they had the order approved through GM based on codes it was throwing .... NEVER showed a CEL by the way..... I know I was having some hesitation issues when it was cold for a couple weeks before all this happened, I threw in some injector cleaner in the gas tank, filled it up and ran it a few days ... the hesitation lightened up, but it never went away completely.. Carbon buildup maybe ?? Who knows ... I just know it's going to be nice to store the car with a brand new motor

Side note, out of the like 4 SS/SC's in town here, two are down... mine with the engine, another guy I know had fragged his tranny and I heard his car had been sitting there for a few days ... I talked to one of the techs that I know, and he told me that the other guys car was leaking fluid from just about anywhere that had any, and the tranny was basically grenaded ... he had 2nd and 4th gears but everything else was shot ....

Not a good week for the area Cobalts I guess

From one of the techs there .....

"When Dean brought the Cobalt in I was like oh wow that is screwed up. I did, acutally, take my own little tour around the car (Mechanical stuff). To me I think the roller followers are making the noise. I am not saying you did, someone probably accidently went over redline and something broke loose on the valvetrain. Thats what I would do first is take the valve cover off first. But GM says that if there is a certain noise complaint then the whole engine needs replaced. They say don't rebuild it, replace it only! "

 

Hmm complain there is engine noise and get a new engine. seems logical.....NOT!!!

 

Don't hate ...

 

i covered my ass. when i first got mine, it made a funky noise, like the tensioner was loose or something. i know how to avoid this noise now, but i rarely do it. anyways, i took it into the dealer, they had it for a couple days trying to locate this noise. none could be found. so it is on record that there is a "customer stated noise". so that part is covered if i have issues. mine has randomly studdered at 6800, hell it's done it at 3000. it hiccups occasionally. it has done this since day one, but nothing to the degree of going blamo. that i know of. compression test in all cylinders was within 1-2 psi of each other

 

Yeah I hear you on that one ......

Keeping the old motor may be in the works as well

I'd love to build that badboy ..... It doesn't seem like it's toast beyond repair to me..

 

So what exactly can this lil motor take in stock form, with a good tune offcourse. I was talking to a local SS owner and he told me that the engine itsself is good for around 400whp?

If thats the case, this is rite around the same power level as a SRT4.

 

The LSJ can take atleast 20lbs of boost stock. So if you use a Turbo to make a very efficient 20 lbs and move a lot of air, then you can definately get over 300whp with the stock motor.

 

a better question is, how much cylinder pressure can it take before it barfs a ring land.

 

GM claims with the eaton and stock pistons, no more than 300hp worth, lol. Apparently the top compression ring or something is in a bad spot. I foget the details, but its more so a bad design than weak pistons. Forget where I read that too.

 

think about this one for a second.

i was thinking about this the other day, while sitting on my thrown in the office. the larger opening of the blower is closer to the throttle body. number 4 is also in that same general area. Hahn maybe onto something when they stated that number 4 was getting more air then the others. common sense could say this, and science could prove this wrong. just a random thought.

who knows, thats just me thinking.

so, the 300 to the tire, or the crank.

 

I don't know, GM just says 300HP. I would say probably crank. Which if you take into the account the power it takes the blower to spin, is probably between GM Stage 2-3.

 

which puts most of us in that zone. then again, this weird hiccup that people are saying happened to them. well it happened to mine when it was just stage 2. no one has really gone into detail as to what the piston protection does. back timing off and dump fuel? or just dump fuel like the cot does? then again, i don't beat on my car enough to even worry about popping it right now