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Possible blown head gasket????

This is a discussion on Possible blown head gasket???? within the Internal Engine forums, part of the LSx Technical Help Section category; 9 lbs. isn't all that much boost for a stock shortblock. I'm willing to bet it had to do with ...

  1. #21
    Moderator Firebirdjones's Avatar
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    9 lbs. isn't all that much boost for a stock shortblock.

    I'm willing to bet it had to do with a tuning issue or possibly fuel pressure drop causing a lean spike, or something along those lines.

    Looking at the first picture closely, you can see very small silver specs laying on top of the piston. Those are pieces of aluminum from excessive heat, which was my first indication of detonation.

    I've seen quite a few naturally aspirated engines do this very same thing when they go lean,,,,right before they snap a ring land.

  2. #22
    Member Jay37's Avatar
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    In all reality we don't have to much info here, and neither one of us have the engine in front of us, but to voice my opinion here. Just to display the other side of possibity's.

    I agree there possibly was detenation, or as some of us call a backfire lol. But the question is did the lean mixture cause the back fire, did the H20, did the boost? Maybe the piston was tired. I am use to a lean mixture looking like the cylinder had shotgun bb's dropped in it. Litterally guys will think some one vandalized there engine and you have to explain it just got ran lean. In his case that sign isn't there. I have seen alot of engines ran lean, and everyone looks like there was bb's dropped in it. I clearly remember the first one, very suprising. Even if it was, THE LEANER THE MEANER TILL IT CAN'T LEAN NO MORE! I don't know if that's applicable in Mr. Grigo's case, but I know I sure as hell have blown up one or two trying to win a race and my last shot was leaning it out. Also in order to detonate, for the chemists it's technical term is "diesel effect" or "compression ignition". You have to look at quality of fuel, cylinder temps, possible hot spots. (side note, It is very possible that a "loose" yah I said it loose ring gap could have saved the engine, because lets say it got hot, causing ring gap to come to zero then because the ring can't expand any more it creates extreme friction, causing the hot spot, and that's were it lights off at the ring.) So if your seeing pistons blow apart like that I would start setting looser ring gaps.

    Every boosted engine should have a looser ring gap then an n/a engine. That's why I never recommend BOLTING on boost. No body started doing that stuff up untill the past few years. That is why I won't do it for anybody. I might be loosing money, but I still sleep good at night. And gentlemen with the issue here I think its hard to fight that theory.

    Mr. Grigo- Trust me I would do it on my own engine, if on a budget, but for the sake of browsers, and weekend warriors is why I don't recommend it. Cause every kid with 4g will think he can boost his LS.[edit] and my patience is starting to get short with these punks that have never changed a spark plug but because they read a forum, they think they know how much it cost's to boost there engine, and feel obligated to "school me" (I think that's what the kids say) on superchargers. I just want to slap there dad. Had to vent, been a relevent topic since I opened up to gen III stuff.
    Last edited by Jay37; 01-25-2011 at 06:35 PM.
    RUDE, CRUDE, AND SOCIABLY UNACCEPTABLE.

  3. #23
    Member youngrigo's Avatar
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    Quote Originally Posted by Jay37 View Post
    Hell, Mr. Grigo that's impessive. Two pistons, head gasket/head and such.

    I think the question here is how many passes/miles were you able to get on the short block? My vote is next you see how much boost an LQ9 will take, stock block stock heads. Just a thought.

    It's cool to see shit get pushed to the breaking point. And I think it takes alot more balls and heart to push something to the breaking point yourself, much respect. seriously.

    ...if you never fall off the edge how do you know your living on it?,
    Happy wrenchin,

    Jay.
    The engine had 60k on it. with the blower the motor had about 10k. 8 out of the 10 have been driven hard!

    I have alot of passes down the 1/4 track! alot of low 11s @ 126-128 shifting at 65-6700 rpms. Those RPMs are pushing it on a stock block and heads.

    As far as counting passes i would say probably cloese to 100 down the track and a whole lot of street races. I knew the block would blow at some point!

    Quote Originally Posted by Firebirdjones View Post
    9 lbs. isn't all that much boost for a stock shortblock.

    I'm willing to bet it had to do with a tuning issue or possibly fuel pressure drop causing a lean spike, or something along those lines.

    Looking at the first picture closely, you can see very small silver specs laying on top of the piston. Those are pieces of aluminum from excessive heat, which was my first indication of detonation.

    I've seen quite a few naturally aspirated engines do this very same thing when they go lean,,,,right before they snap a ring land.

    I havent data loged it to see what really happened but it was really cold out... The air was alot denser! so i know that had a part to play with it. Aswell as maybe a fuel pressure drop.... It was on my 5th run of the night that it blew. If i had to put money on it... it is that it spike leaned for whatever reason...

    But hey 2 years plus at that power on a stock block and heads.... We all new i would see this day!

  4. #24
    Senior Member redbird555's Avatar
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    Quote Originally Posted by Jay37 View Post
    Hell, Mr. Grigo that's impessive. Two pistons, head gasket/head and such.

    I think the question here is how many passes/miles were you able to get on the short block? My vote is next you see how much boost an LQ9 will take, stock block stock heads. Just a thought.

    It's cool to see shit get pushed to the breaking point. And I think it takes alot more balls and heart to push something to the breaking point yourself, much respect. seriously.

    ...if you never fall off the edge how do you know your living on it?,
    Happy wrenchin,

    Jay.
    Just curious why would you want to run an lq9 block for this little boost? He didnt even come close to the limit of the block just the pistons which are the same in the lq9 anyway plus the lq9 has almost the same compression this motor did so it would probably yield similiar results. Unless hes gonna run 20lbs of boost i'd keep the stock aluminum block and just lower the compression a little bit so he can get even more boost and/or do forged pistons to help also, a rod upgrade is also probably needed here to.

  5. #25
    Member Jay37's Avatar
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    Mr. Grigo- 100 passes=epic, IMO you cheated the system, and me being a pirate at heart, I love it! True hot-rod enginuity.

    ---------------BACK TO THE BROWSERS-------------
    "detonation" "diesel effect" "compression ignition" REQUIRES a few things

    Pressure, Heat, Combustable mixture.- that is not debateable it science.
    So in the case of me not supporting a "non gearhead" running this set up. The setup being bolting boost on a short block.

    Let's break down the requirements to blow an engine with detionation.

    First we will do "Pressure" which translates to compression-So most people say 11 to 1 is safe with these aluminum engines. Problem is with boost now you have to calcuate static compression, which involves alot of variables, meaning it could change dependent on pre-charge dependent on cam, boost, and whole lot of other variables. So there we have one loose animal.

    Second we have "Combustable mixture" So grade of fuel and mixture.I.E. running bad gas, or running lean like previously mentioned by these gentlemen. So if you run a little lean or get bad gas your putting your self in serious risk... once again.

    Third we have "Heat" So cylinder tempature. I.E. The engine getting over heated. But you could also have a "Hot Spot" which would be an outlier, meaning an isolated heat concentration, that alone can greatly reduce, the amount of "Pressure" and "combustable mixture" required to cause detonation. So another I.E. stock ring gap can give you a hot spot, putting you at risk.

    None of these variables alone will cause detonation. But every stick cut short puts you closer. It's science.
    Last edited by Jay37; 01-25-2011 at 08:13 PM.

  6. #26
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    Quote Originally Posted by redbird555 View Post
    Just curious why would you want to run an lq9 block for this little boost? He didnt even come close to the limit of the block just the pistons which are the same in the lq9 anyway plus the lq9 has almost the same compression this motor did so it would probably yield similiar results. Unless hes gonna run 20lbs of boost i'd keep the stock aluminum block and just lower the compression a little bit so he can get even more boost and/or do forged pistons to help also, a rod upgrade is also probably needed here to.
    I hear that bro.

    It's because you would have less flex, and allow less stretch, taking out some of the variables. Everything happens for a reason.
    Thats why the lsx block is steel, and has an extra head bolt.
    I'm not saying an aluminum block is week. Just would be giving the engine a better shot at holding up.

    Small steps.
    Last edited by Jay37; 01-25-2011 at 07:09 PM.

  7. #27
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    Quote Originally Posted by Firebirdjones View Post
    9 lbs. isn't all that much boost for a stock shortblock.

    Looking at the first picture closely, you can see very small silver specs laying on top of the piston. Those are pieces of aluminum from excessive heat, which was my first indication of detonation.

    I've seen quite a few naturally aspirated engines do this very same thing when they go lean,,,,right before they snap a ring land.
    Bear with me guys, I am almost done.

    So with the science here, what I'm saying is the lean mixture allowed detonation, the specs are from the ring gap closing and scraping the wall causing the heat, and the engine is boosted, possibly to close to comfort. I am just not comfortable recomending edgy engines, meaning one variable goes bad and boom!

    Loose any one of those variables and the engine probably would not have blown.

    If the engine was just to lean and not to close for comfort it most likely would not have detonated.(similiar to how a bad bearing and a pressure in a diesel engine crankcase can "detonate" the crank case and light off the oil vapors causing an "explosion", it wouldn't happen if that bearing didn't overheat, or in our case the stock rings over heat.)

    So if your saving money for years for a biuld, this is something to think about.

    I apoligize I used your engine as the example hear Mr. Grigo, this was not at all directed to you, I respect enginuity more than anything, I wish more people had it, I might not get paid as much if they did, cause I would have to pick a different career, but I also wouldn't get irritated as much haha. Maybe they (keyboard gearheads) will realize just how COMPLICATED this shit really is.
    Last edited by Jay37; 01-25-2011 at 08:19 PM.

  8. #28
    Member youngrigo's Avatar
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    I drove the shit out of this engine.... Everybody knows that if your making over 500rwhp that you start to push the stock block.... I new that running it as hard as i was as often and taking up the RPMs to 6500 the motor would one day blow.... Thats why im not bummed about it! Its all part of the game.... In this game shit will break and thats when you upgrade it IMO.... I pretty much push everything to the limit break it then upgrade it.... lol

    It helps alot tho if you do your own work....

  9. #29
    Member youngrigo's Avatar
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    Keep in mind... It could have also been a bad batch of gas

  10. #30
    Senior Member redbird555's Avatar
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    Quote Originally Posted by Jay37 View Post
    Bear with me guys, I am almost done.

    So with the science here, what I'm saying is the lean mixture allowed detonation, the specs are from the ring gap closing and scraping the wall causing the heat, and the engine is boosted, possibly to close to comfort. I am just not comfortable recomending edgy engines, meaning one variable goes bad and boom!

    Loose any one of those variables and the engine probably would not have blown.

    If the engine was just to lean and not to close for comfort it most likely would not have detonated.(similiar to how a bad bearing and a pressure in a diesel engine crankcase can "detonate" the crank case and light off the oil vapors causing an "explosion", it wouldn't happen if that bearing didn't overheat, or in our case the stock rings over heat.)

    So if your saving money for years for a biuld, this is something to think about.

    I apoligize I used your engine as the example hear Mr. Grigo, this was not at all directed to you, I respect enginuity more than anything, I wish more people had it, I might not get paid as much if they did, cause I would have to pick a different career, but I also wouldn't get irritated as much haha. Maybe they (keyboard gearheads) will realize just how COMPLICATED this shit really is.
    I agree detonation or something similiar is probably what caused this 500rwhp is a lot to push through a stock shortblock with no internal upgrades. However people sleeve ls1 blocks out to 427 all the time and texas speed even has one thats in the 9's so i think hell be fine with the stock aluminum block but if he wants to do an lq9 its up to him. However mr. grigio what are you plans for the new motor? I imagine the stock crank is fine and is capable of big power the rods ehhh I'd replace with something better, Jay is right though also the compression and boost were probably a little high for comfort. Thats why I was suggesting forged pistons maybe with a dome in them that way you'd gain strength, knock down the compression, and as Jay pointed out you would have a larger ring gap which could help also. GOOD LUCK

  11. #31
    Member youngrigo's Avatar
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    I may just rebuild this block with forged pistons and rods stock crank.... Cheap and will handle alot of boost!

    Throw some 317 heads and a bigger cam. Then call it a day. Simple, cheap and should handle 700rwhp

    Possibly looking for a 9.5CR...

  12. #32
    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by youngrigo View Post
    The engine had 60k on it. with the blower the motor had about 10k. 8 out of the 10 have been driven hard!

    I have alot of passes down the 1/4 track! alot of low 11s @ 126-128 shifting at 65-6700 rpms. Those RPMs are pushing it on a stock block and heads.

    As far as counting passes i would say probably cloese to 100 down the track and a whole lot of street races. I knew the block would blow at some point!




    I havent data loged it to see what really happened but it was really cold out... The air was alot denser! so i know that had a part to play with it. Aswell as maybe a fuel pressure drop.... It was on my 5th run of the night that it blew. If i had to put money on it... it is that it spike leaned for whatever reason...

    But hey 2 years plus at that power on a stock block and heads.... We all new i would see this day!
    That explains alot. With a colder temp, lower DA's, the engine will want more fuel. Becomes more critical on a boosted application.
    Those little specs I see on the piston are specs of aluminum. I'm willing to bet if you look at the spark plug closely, you'll also see those specs. If you look down into the porcelin portion of the plug and see black specs, that's signs of detonation as well.
    It is possible the top ring butted together, which also breaks ring lands from pistons, and this usually is more critical with hyperutectic pistons because they have a different expansion rate than a forged piston. I know KB requires larger top ring gaps on their hyperutectics and it varies depending on the use of the engine to avoid butting the rings together.
    In your case, being only on 9lbs. of boost and running this engine for as long and hard as you did,,,I don't think that's the case here.
    I'm still leaning towards a lean condition judging by what I'm seeing. Whether it was a freak thing, fuel pump issue, tune,,,,doesn't matter, I wasn't trying to point fingers at anyone. Just giving you a heads up so it can be corrected on the next build.

    Not that it really matters now anyway, it's a bit late for that Now you can go forged and turn the wick up and have some real fun.

  13. #33
    Member youngrigo's Avatar
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    I believe the DA that day was something in the -800....

  14. #34
    Senior Member redbird555's Avatar
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    oooo ya that'll do it. all in all thats what i would have guessed to begin with. most people that ive seen blow their engines due to going lean blow that 7 ringland not sure why it just seems like that cylinder runs leaner on these motors. 317's should be a nice setup along with the forged internals good luck!

  15. #35
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    Quote Originally Posted by youngrigo View Post
    I drove the shit out of this engine.... Everybody knows that if your making over 500rwhp that you start to push the stock block.... I new that running it as hard as i was as often and taking up the RPMs to 6500 the motor would one day blow.... Thats why im not bummed about it! Its all part of the game.... In this game shit will break and thats when you upgrade it IMO.... I pretty much push everything to the limit break it then upgrade it.... lol

    It helps alot tho if you do your own work....
    I totally agree. Just not the part were everybody understands about pushing the stock block. I see alot of guys get confused on a stock block vs. a stock short block vs. a stock long block. You might not believe me but I'm not bullshitting.

    Your new biuld sounds bad ass, more bad ass then the other one. can't wait to hear about it!
    good luck.

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