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Thread: Blown engine theory

  1. #21

    Default Blown engine theory

    Mate I am truly sorry to hear about your misfortune and I understand your need for an explanation. I commend the guys for searching for an explanation. But I don't buy the hydro lock theory one little bit, it's fanciful at best. I also think it's curious that no body has asked if the supposed hydro lock was caused by excessive flow from a WI system?

    Cylinder pressures will produce the same results, you don't need to have a fluid in there to bend the rods. I don't understand why cylinder pressures are being overlooked in this discussion. Probably because cylinder pressures aren't going to make money for the theorists who have something to sell.

    The most useful thing I can add is that I've had the low-rpm high-load studder a few times, usually while cruise control is active. It produces a metallic rattle with a James Bond smoke screen out the back. Perhaps I've been a whisker way from the catastrophic result you had? I don't know, but based on discussions I've had with Mazda engineers in my view it's a software issue and I won't be spending money on any WI or other snake oil solutions anytime soon.

    Gone to Volvo


  2. Default

    Your comments on WI I think are unfounded as very few cars with meth have blown. I am one of the lucky few . WI is certainly not snake oil and is a technology that goes back to fighter planes in WW2 and the benefits are proven. There is no way in hell the amount of spray going through this system could hydrolock the motor (it would undoubtedly be vapourised once it reaches the cylinder anyhow). Good business is to find the real solution and market that. Those that sell crap and tell lies will disappear quickly. Who are these 'Mazda engineers' and if they have answers why don't they step forward with their theories? They can maintain a cloak of anonymity on a forum like this. OK to sh!t on ideas as long as you can disprove them or have a valid alternative theory.
    Last edited by Cosmic3MPS; 04-05-2009 at 12:18 AM.


  3. #23

    Default

    You're not the only person to spend money on a damaged engine. I've rebuilt a few blown engines and I've learned a few things along the way. My comments were intended in good faith and I'm sorry you didn't take it that way.

    BTW I'm not dismissing the theory of WI. A B52 carries 12 tons of water and burns it all in 60 seconds during takeoff. So what? We're not at war. We should be able to tune these engines without band aids like WI.

  4. #24
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    Default

    Quote Originally Posted by kmh001 View Post

    The most useful thing I can add is that I've had the low-rpm high-load studder a few times, usually while cruise control is active. It produces a metallic rattle with a James Bond smoke screen out the back. Perhaps I've been a whisker way from the catastrophic result you had?
    High-load low RPM stutter - actually noticed this tonight.
    What is the significance? (please enlighten me)
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  5. #25
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    I am finding the oil control theory fairly convincing myself - the motors are hydrolocking on oil after some kind of catastrophic failure of the oil control / pcv system - oil getting sucked through the engine.

    I am struggling a little to understand how PCV valve alone could flow enough oil, how it could fail so completely to do it's job, or where else the oil could come from - I understand that there are two possible routes for it to take as far as getting sucked through goes (?)

    The melting around the oil control ring ring land strikes me as just plain bizarre. I have previously read that some US modders with catchcans were catching quite a lot of fuel as well as oil - if they emptied their can and let everything settle there was quite a lot of fuel in there.


    So the questions seem to be how is the oil getting up top and how is the fuel getting down below?
    Is there any way the HPFP could be causing fuel to get into the bottom end?

    That Cosmics had oil all through the cooler and exhaust seems to point in the direction suggested here, and the severe knock with smokescreen described by kmh001 below sounds very much to me like a less severe event without the hole-in-the-block result, which is perhaps made that much more likely the more severe your mods.

    Quote Originally Posted by kmh001 View Post
    ... I've had the low-rpm high-load studder a few times, usually while cruise control is active. It produces a metallic rattle with a James Bond smoke screen out the back...
    Last edited by Nexus; 04-05-2009 at 12:59 AM.

  6. Default

    Quote Originally Posted by kmh001 View Post
    You're not the only person to spend money on a damaged engine. I've rebuilt a few blown engines and I've learned a few things along the way. My comments were intended in good faith and I'm sorry you didn't take it that way.

    BTW I'm not dismissing the theory of WI. A B52 carries 12 tons of water and burns it all in 60 seconds during takeoff. So what? We're not at war. We should be able to tune these engines without band aids like WI.
    Not sure how I should take a comment like WI is snake oil. More confusing is this post that shows WI is a proven technology (only to be used in war time of course). WI will of course be a useless defence if oil-hydrolock is occurring but that does not negate its anti det properties. It is also not restricted in operation by the Mazda electronics but can be delivered consistently regardless of what the ecu is doing. Add to that cooling and cleaning effects and you have a solid enhancement for FI engines.
    Last edited by Cosmic3MPS; 04-05-2009 at 10:44 AM.


  7. #27
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    Default

    Following thought re: fuel getting into the bottom end somehow

    Let's say a certain amount of fuel has made it's way into the bottom end by unknown means - HPFP doing something wack, or however. If it wasn't happening, it wouldn't be in oil catch cans...

    Let's say that fuel slowly builds up, perhaps at cruising, until there is a great enough concentration of it that it lights up under the pistons. Perhaps the oil control ring land is the ignition point for this wayward fuel.

    If there is sufficient fuel to ignite under the piston, that's potentially going to create a huge crankcase positive pressure.

    Could that not account for oil being forced through the PCV patchways, into the intake and from there produce hydrolock?

    Piston temps would very quickly increase abnormally because the oil spray underneath that is supposed to cool them is actually an area of ignition.

    So pistons start melting and oil is forced through producing hydrolock and the rest is history...No PCV valve failures required, just massively abnormal crankcase pressure.
    Last edited by Nexus; 04-05-2009 at 10:34 AM.

  8. Default

    I think its great to look at all of the theories.. The hardest thing here is to prove it..

    I doubt you'll have any Mazda techies coming forth with info on this, as if the oil theory is to blame for the KA-Boomskies, then this would probably warrant a total recall, and Mazda would have to spend up big on a total engine re-design..

    In my mind, I think the oil theory could be a major cause, but I also think its one of many chain reactions to the first action.

    I still believe that the rods are being very slightly bent in the first action (but within tollerances allowing the motor to still function for a small period), which then causes the chamber breach, and allowing oil to get past the seals and causing a hydrolock.

    Alternatively, unburnt fuel would also be able to escape past the seals into the crank at WOT at low revs. This fuel is then able to ignite under the cylinder head causing enough heat to further weaken and compromise the rods.

    Either way, I consider the rods and the head pins to be the weak point in the MZR 2.3ltr engine.

  9. #29

    Default

    Quote Originally Posted by Cosmic3MPS View Post
    Not sure how I should take a comment like WI is snake oil. More confusing is this post that shows WI is a proven technology (only to be used in war time of course). WI will of course be a useless defence if oil-hydrolock is occurring but that does not negate its anti det properties. It is also not restricted in operation by the Mazda electronics but can be delivered consistently regardless of what the ecu is doing. Add to that cooling and cleaning effects and you have a solid enhancement for FI engines.
    I'm just opposed to WI because it's an inelegant and outdated solution. To take the aviation analogy a bit further, aircraft engine designers stopped using WI decades ago because engine technology advanced to the point where it's no longer needed.

    Using the aforementioned B52 example again, with 1940's technology it takes 8 engines, 12 tons of water and copious amounts of fuel to lift an 83 ton aircraft into the sky. Today we have 350 tonne aircraft doing it with 2 engines and a fraction of the fuel. I'd prefer it if we didn't need WI because our developers got with the times and did a better job.

    For the guys pushing the limits with race engines WI is fine, but for a daily driver I just think it's an undesirable alternative to better design. That's why I call it snake oil.

    I'm also a bit skeptical of the guy on MS forums who keeps wheeling out these implausible theories whenever he has something to sell. And I don't care for his scaremongering.

    One of the problems with these discussions is they can be too narrow and some of the less experienced younger guys treat these issues like they've never happened before. And there are a multitude of aftermarket companies that perpetuate myths to exploit their inexperience.

    Many of these issues are not new at all. For example 20 years ago I ran a V8 with a 5 litre catch can which would fill in about a month. That's normal. Although with today's engine tolerances you would expect it to fill less quickly.

    Fuel in the oil is also normal. Every piston engine has fuel in the oil. If you run a catch can it will collect the fuel and other light-weight vapors because that's what it's designed to do. It's not an abnormality.

    I'm not claiming to have the answers, I'm just saying I've seen these diagnostic discussions explore outlandish theories so many times and they always come back to a normal explanation and solution when the appropriate expert gets involved (I don't mean me). So with that background I'm automatically cynical of theorists, especially those with something to sell.

    If you hole a piston you're going to get oil right through the engine. That's entirely normal, but this is the fist time I've ever heard anyone suggest the oil caused the hole. I've had experience with excessive oil entering the intake. My old V8 again, it used to push too much oil through the pushrods and the rocker covers would full with oil to the extent that it poured through the pcv and into the intake. The smoke out the exhaust was incredible. The engine had a similar 9.4:1 compression ratio, but no bent rods and no holed pistons.

    Detonation bends rods and holes pistons all the time and that's what I think the problem is. I really don't understand why this is being ignored. I'd prefer to focus on why the engines are detonating.

    Jmac to answer your question I think the low-rpm high-load studder is the same detonation that blows these motors. If it's a less severe occurrence you just keep driving and forget about it, if it's a more severe occurrence you have a broken engine.

    That's just my opinion and I have no evidence to support it other than the lack of evidence to the contrary. I'm happy to be proved wrong.

    As for the fuel burning in the crankcase theory, I've worked with large diesel engines that have a proclivity for crank case explosions and have explosion plates built into the crank case to mitigate the destructive effects. I've seen what happens when they explode and I'm certain that if any combustion occurred inside our crank cases there would be a hell of a lot more damage than a bit of melted piston. The results would be catastrophic. Again I say BS to that theory.
    Last edited by kmh001; 04-05-2009 at 01:22 PM.

    Gone to Volvo


  10. #30
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    Default

    Quote Originally Posted by kmh001 View Post
    .... The results would be catastrophic....
    How exactly does a hole in your block not qualify as catastrophic?

    A certain small amount of fuel in oil sure. Lots of it, hell no. Enough for it to ignite? Hell no. It doesn't have to burn explosively - it's diluted with oil once it's in there. It just has to reach a concentration where it ignites and create abnormal temperatures and abnormally high crankcase pressures.

    Snake oil, BTW, is traditionally considered a total fabrication that has no effect whatsoever. Since WI clearly has an intended and proven outcome, there's no grounds to call it snake oil.

    If you want to call it a band-aid, I think that could be reasonable.

    Quote Originally Posted by kmh001 View Post
    ...If you hole a piston you're going to get oil right through the engine. That's entirely normal, but this is the fist time I've ever heard anyone suggest the oil caused the hole...
    Have you actually read the MS forums article in detail? The engine they pulled down did not have holed pistons. There is no suggestion whatsoever that oil caused a holed piston.

    I know this is a contentious subject. Please lets try and keep this thread focused, civilised, and addressing the various data without going off half-cocked etc.

  11. #31

    Default

    Ok snake oil is the wrong term, WI is a band aid. And I still don't want 1940's technology on may car.

    Correct me if I'm wrong because I'm not gonna waste my time reading it again, but I though I read that the hole in the block was the result of mechanical damage from a liberated part, not the result of a crank case explosion.

    And yes I have read the MS forum and there is discussion of holed pistons. I've stayed right on topic fella. The issue here is that the theories are not staying on topic because they are not anywhere close to explaining why these engines are blowing. If you think my post was in anyway off topic and uncivilised then I wont bother contributing to this fairytale thread any more.

    Gone to Volvo


  12. #32
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    Sorry you've taken offence, kmh001. Your discussion may be on topic but your approach is needlessly aggressive and failing to add constructively to the discussion.

    The admonition to keep things civilised is not a comment just for your eyes alone, it's a request for everyone involved. It's a contentious subject, as you are demonstrating very well, and I would like to see us keep the discussion constructive.

    It is likely in a catastrophic failure of this kind that parts will be damaged and pistones holed etc. etc.

    This is a discussion of technical info, and as such, accusations "snake-oil" and "fairytale" are inappropriate, and contribute nothing but to reinforce your own opinion, except perhaps to underline why I am asking everyone to keep it civilised/chilled/sensible/measured/whatever.

    You provide no alternative theory, and fairly spurious data to back up your own opinion.

    Re: Discussion of holed pistons : The theory in question is based on the pull-down of a failed motor that did not destroy the block or pistons. Quote "to my suprise there were no holes in the pistons." Unquote.

    So you can see your assertion "this is the fist time I've ever heard anyone suggest the oil caused the hole." ( re: pistons) is clearly and unquestionably incorrect, and is leading the discussion off track, and "going off half-cocked"

    For the last time, cool it or can it.

    May I suggest for the time being that we restrict discussion to the specifics of the pull-down in the MS thread that has kicked this off?

    Quote Originally Posted by kmh001 View Post
    Ok snake oil is the wrong term, WI is a band aid. And I still don't want 1940's technology on may car.

    Correct me if I'm wrong because I'm not gonna waste my time reading it again, but I though I read that the hole in the block was the result of mechanical damage from a liberated part, not the result of a crank case explosion.

    And yes I have read the MS forum and there is discussion of holed pistons. I've stayed right on topic fella. The issue here is that the theories are not staying on topic because they are not anywhere close to explaining why these engines are blowing. If you think my post was in anyway off topic and uncivilised then I wont bother contributing to this fairytale thread any more.
    Last edited by Nexus; 04-05-2009 at 03:02 PM.

  13. #33
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    Default Restart

    Just to restart the stalled discussion; kmh001, I do appreciate your input, but the delivery left a great deal to be desired. I'm no expert, and in some ways I agree with you regarding vendors who declare "this is what you need to avoid a disaster" - taking it with a grain of salt is in order

    Having said that, a certain amount of benefit of the doubt is also in order, until proven otherwise.

    If, as I am theorizing, a slow-burn of fuel in the bottom end, resulting in abnormal temps and pressures is inducing similar failures - forcing oil through the intake and PCV's - is what is taking place (big IF) - wouldn't this mean that no amount of tinkering with the PCV systems would make any difference?

    If fuel in the bottom end was igniting and causing an issue, as the melting oil control ring land seems to indicate, then surely the only way to stop this is to stop the fuel contamination in the oil reaching a concentration where an ignition is possible?

    Tinkering with PCV systems might then be barking up the wrong tree, as it could be expected the (theorized) abnormally high crankcase pressure would overcome almost any modification to the PCV system one can think of.

    I am no mechanical expert, but I do have an understanding, and significant experience in investigative research.

    Now I might be asking those with more detailed mechanical knowledge to spell it out to us in tedious detail how some of these ideas are or are not viable, but ultimately that is what the thread is for.

    Clear, detailed analysis of ideas and facts are what is called for here. Now; if we can discuss this without resorting to blanket dismissals without specific detail and getting up each others noses, let's get to the meat of it.

    The failed motor pull-down referenced in the MS thread is our baseline for discussion - I'll shut-up now and let the real mechanics say their piece; Measured, clear info without emotive venting please.

    kmh001, that is a specific invitation if you're up for it.

  14. #34

    Default

    I read the linked thread.... but can't see the pictures..... and I'm not about to join another Mazda site..... I'm here because of the Aussie FWD Turbo enthusiasts.... not really the MPS itself.

    Can someone who has a log-in please copy post the pictures in here ?

  15. Default

    Quote Originally Posted by ChaMPS View Post
    I read the linked thread.... but can't see the pictures..... and I'm not about to join another Mazda site..... I'm here because of the Aussie FWD Turbo enthusiasts.... not really the MPS itself.

    Can someone who has a log-in please copy post the pictures in here ?
    I think you Focus XR5 boyz are lucky. I've not heard of any of those volvo 5potter's blowing, even after mods... Bl00dy mazda.....

  16. #36

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    Quote Originally Posted by Wardski View Post
    I think you Focus XR5 boyz are lucky. I've not heard of any of those volvo 5potter's blowing, even after mods... Bl00dy mazda.....
    I tend to agree..... but I can also think of one or two T5's that just didn't want to play.... not as catastrophic as this though.....

    Pictures, anyone...... Please

  17. #37
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    Default

    I'll check with the MS thread owners for permission to re-post pictures and content. Patience please.

  18. #38

    Default

    Mate if you want real mechanics involved don't invite me back into the discussion.

    I read so many long threads on the MS forum that I can't pinpoint where I saw it. But I clearly remember reading that one of several engines pulled down had holed pistons and it was asserted that hydro lock caused by oil caused the holes. Are you sure you've read all the threads?

    If my tone was aggressive it would have been because of the "if you don't buy my latest gadget your motor is gonna blow next Thursday" crap that was going largely unchallenged. Harry was the only voice of reason in those discussions. He was trying to keep the discussion real but not having any luck. I found reading those forums was like being in the twilight zone, the line between reality and fantasy was very blurred.

    Finally, I have to correct one thing. I have in fact offered an alternative theory. I think I've said at least twice that I believe the damage to these engines is resulting from plain old boring detonation. It's actually not a theory, it's common knowledge that detonation is the default cause of bent rods in piston engines. In very rare cases a physical obstruction like a dropped valve or water ingestion will bend a rod. But in the proverbial 99% it's detonation.

    Like I said, I am or at least was interested in finding out why these engine are blowing but given the direction these discussions are taking I don't believe that answer will be provided so I'll leave it to those who want to theorise.

    Gone to Volvo


  19. #39
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    Call for "real mechanics" was slightly tongue-in-cheek. I hope we can enjoy discussing it and learning without needing to be qualified mechanics to gain understanding. That's one of the reasons many of us are on ozMPSclub.

    The suggestion that this is plain old ordinary knock induced failure is perfectly reasonable.

    There are some questions that evidence from the pull-down raises that don't seem to be adequately answered by this scenario.

    I won't pose the questions myself right now, as the images will go a long way towards clarifying the supposed anomalies. I'd happily just copy them, but it's poor etiquette. Not sure how soon I will be able to get the OK, if at all. Not tonight, as I'm off to bed!

    Here's to some hopefully enlightening inspection and discussion of the internals of our MPS engines.
    Last edited by Nexus; 05-05-2009 at 08:20 AM. Reason: typo

  20. #40

    Default

    scaryness

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