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Engine Disaster Henry J

Discussion in 'The Hokey Ass Message Board' started by swade41, Sep 26, 2011.

  1. Good to see the builder doing the right thing. Word does get around either way, better and cheaper in the long run to protect his reputation.

    Bob
     
  2. CutawayAl
    Joined: Aug 3, 2009
    Posts: 2,144

    CutawayAl
    Member
    from MI

    and...... if you plan a significant overbore again sonic check the block first. Also, don't dismiss the distributor curve post I made earlier.
     
  3. I just went through this whole thread for the 3rd time and I noticed that one of the first pictures shows the side of the block that was whole. I noticed that the first piston was twisted a few degrees. Could have been the camera angle but if this is true I am guessing that the pistons were sub par and broke through the wrist pin due to a bad set of pistons. Also when running aluminum heads you can run more compression due to the superior cooling of the heads. And last but not least I saw no indication of detonation at all. If it was detonating there would be signs of it on the tops of the piston such as small holes. Kinda like someone had been at them with an Ice pick. It is good he is going to help you redo it but I would be careful of his quality after this.
     
  4. Some good questions John, maybe I can help. The piston pins would have been pressed thru the rod small ends and float on the piston pin bores. Looking close at the one picture, and I dont see any signs of galling, excessive heat or blueing, displaced metal from the pressing op etc., on either the piston pin bores- {on the broken piston dome piece}, or any real damage to the pin- { other than the little chip at the one end }. Not a real good picture, but I dont see signs of using a " rod heater ", so safe to say they were pressed. That said, the piston could have easily been cracked and damaged- pressing the pins thru the press fit of the small end of the rods. I like my idea of the piston shattering due to excessive PTW clearance OR harmonics from NOT having the rotating assembly properly balanced, than that and I'll tell you why. If the piston was cracked pressing the press-fit-pin thru the piston, I dont think it would have lasted as long as it did. I believe it would have let go, the first time Phil hammered it. Especially being a cast piston. Looking at the pics again, I see one rod small end balance pad, and again, appears to have zero weight removed for balancing. I would love to see all the rod small ends to compare. Again, this is simply just my suggestion and food for thought. TR
     
  5. Yes John, almost forgot, the piston to pin clrnce, if that was too small or too tight, again no real signs. It probably would'nt have shattered the piston, but left scoring, galling, and some signs of seizure before breaking the pin boss and piston, hope that helps. FWIW, Ive seen this destruction with Cast Pistons { doesn't matter who made them }, from Nitrous, Forced Induction, Detonation, Piston to head interference, and excessive piston to wall- especially with a cold or not up to temp engine, and of course harmonics. I hope that helps, TR
     
  6. 34toddster
    Joined: Mar 28, 2006
    Posts: 1,481

    34toddster
    Member
    from Missouri

    I think next time around I'd use a Forged piston, not that all of these pistons will do the same I just LIKE forged then I can abuse them at will! Good luck on the newest motor. It's also nice to see someone stand behind the work they do for their customers, that goes a long way with the builder.
     
  7. BadbeatFactory
    Joined: Oct 20, 2009
    Posts: 102

    BadbeatFactory
    Member

    I still want to see a better picture of the pin boss on the broken piston...I believe you will find your answer there.
    ...and the question I had earlier in the thread, were your rods floated on the pin end??
    The reason I am asking is if your pin stopped its rotation or stopped movement in the pin boss, even for an instant, this is usually the result. No other info you have given in the pictures would lead me to think any different...
    There are no signs of piston to wall issues, no detonation, balancing ( I have over balanced and under balanced as much as 200 gr. and torsionally its not much different )...I just dont see any other problem in the pictures given...
     
    Last edited: Oct 4, 2011
  8. Here are two quotes from the Keith Black web-site.
    " Piston fitting for Skirt Coated Pistons ",
    #3- Pistons that have a dry-film lubricant applied to the skirts, are approxiamately .001" larger than uncoated.
    #4- Failure to follow the " RECOMMENDED FINISH BORE DIAMETER " can result in piston failure.

    " Prevent Pin Galling "
    " It is recommended the connecting rod be HEATED and the pin fitted by hand to ensure no damage occurs to the pin and pin bore. Pressing the pin through the rod eye is NOT recommended ".
    Just more food for thought, TR
     
  9. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    X2. ANY failure of a hyper is a catastrophic failure, they just come apart, and the result of a piston coming apart is pretty much always a rod through the cylinder wall. Forgings are far more ductile, and will deform rather than break. I really dont like hypers, they are very unforgiving. Like many others, looking at the signs, I dont see anything on the plugs or piston tops that indicate detonation, but in defense of the engine builder, things look a hell of a lot different, and you can see alot more in person than you can on a photo on a computer moniter. But what I see in the photos looks a hell of a lot more like the classic hyper piston failure that I have seen in the past, than it does like a detonation failure. I would be looking for heavy damage above the top ring land, like the crown broken away down to the land, and heavy black marks in the same area. I dont see any photos of the valves, but there will often also be blueing where the head of the exhaust valve flares into the stem, and you will often see the lash on the exhaust valves tighten up prior to catastrophic internal failure.
     
  10. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Took a good look at the photo with the hole in the cylinder wall, doesnt look thin at all to me. I can only really see directly onto the broken edge at the bottom of the break and a little off to the right, but it looks to be at least .100 in those areas. Looks more to me like the rod knocked a hole in the liner after the piston came apart than the cylinder wall giving up first.
    I do notice a small fracture above the ring land on #2 around 8 oclock. If I am looking at the pics right, the cylinder wall with the hole is #5? Just a guess, but I am going to say the crack in the crown on #2 is from debris from #5 (firing order is 5,7,2 so it would be right in the line of fire) getting trapped between the piston and cylinder head.
     
  11. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    One more comment. The magazines have given engine builders a great out by pumping the dangers of detonation so hard. Not saying that it wont really tear things up, it will, but lately it seems like every time a fresh engine blows up, the engine builder just shrugs and goes "oh, you must have detonated it", and a hell of a lot of guys will buy that without any question. I have looked at a few motors lately where there was absolutely no evidence to support that conclusion, yet that what the guy was told by the builder.
     
  12. I think the short block assembled was right around 2800, with heads and intake installed. The heads and intake were bought seperate, not through the builder. The pistons did have a KB in the first two digits of the part number, don't remember the price off hand.
    He did say the crank was put on a set of "V" blocks and was straight, he also said the cam looks good. He does have a helper in the shop and I think the rods were reused with the big end clearenced to fit the new crank.
    I did not ask for a pro stock engine here, just a solid engine that would live for a couple years before freshing. I told him I was on a budget but didn't want a stock engine either so parts were chosen accordingly. The rpm limit was set at 6300-6500 based on cam and heads, this engine was not an all out race engine by no meens.
     
  13. I just put calipers on a piece of the wall and it was .184
     
  14. nimrodracing50
    Joined: Oct 3, 2011
    Posts: 68

    nimrodracing50
    Member

    Aloha,
    Geez man, looks like some NHRA top fuel explosion. May that motor rest in piece. (or pieces)
    Big Al
     
  15. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Thats actually quite thick for a sbc thats already punched .060. Rules out cylinder wall failure as a factor.
     
  16. There are two deep gouges on opposing sides in the cylinder, probably from the piston before it totaly let go.
     
  17. Did you check the end gap on the rings ?
     
  18. No, once it was at the builders I watched until he tore it down to the short block. Those were the pictures I had, he finished tearing it down after I left. Friday I dropped off the spare block and picked up the broken bare block.
    I couldn't stay because I had to get my young son off the bus, didn't see any other parts.
     
  19. davedeltadog
    Joined: Aug 8, 2008
    Posts: 172

    davedeltadog
    Member

    Hey Phil
    sorry that happened, it realy sucks man
     
  20. Hey Dave, yes it does !
    It was a long hard 10 months building this car to come to an abrupt end, glad I got a little taste of running it down the track though. Next year I plan on having a bit more fun, so look out boys.
     
  21. Hemiman 426
    Joined: Apr 7, 2011
    Posts: 645

    Hemiman 426
    Member
    from Tulsa, Ok.

    Phil...

    Can you post pics of the sides of the other pistons and the cylinder walls??
    I concure with the others as to if there was improper piston-to-wall clearances, there should be indications of scarring. Of what little I see, the walls look in good condition.
    And as to the pistons, as others have stated the side view would better answer the question of detonation.
    What doesn't make sense in claiming detonation is the timing. You said you were having the distributor checked out..anything on that?? If in fact it was 32 degrees, good gas, aluminum heads, and a street compression, there shouldn't have been any problems with detonation ........If you were well above that number, it very well could have been ..
    Sure would like to see those pistons!

    Bill
     
  22. Bill, right now all I have is the block, the rest is still at the builders. I could get pictures of the block, might be late tomorrow night though.
     
  23. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    For me, the jury is still out on what actually initiated the piston failure in #5, But I feel pretty comfortable is saying thats where the carnage started, and the damage in other cylinders is caused by the resulting debris traveling through the rest of the motor. I am leaning towards it starting with the pin/pin boss in #5, but I just dont feel confident making a diagnosis based on photos over the internet. I just cant see enough.
    My feeling is, if this motor had forgings in it instead of hypers, and the pin had been fitted too tight in #5, you would have probably saved the block, although #5 would have probably needed a sleeve due to the pin/pin boss chewing up the cylinder wall. I'm basing this on previous experience with a set of Arias forgings and one tight pin in a 440. Its possible that you may have even gotten away without a sleeve, if you had spotted debris in the oil soon enough. With the hypers, BANG! Its over.
     
  24. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    x2.
     
  25. Those that speak of how it could not possibly be improper piston to wall clearance do not understand fully and or have little actual experience of what they speak of. First off, we are not talking about to tight clearance, yes this would show signs of scuffing. This has been clearly not the case. Excessive clearance on the other hand, with a Cast piston, and a Coated Cast piston, ESPECIALLY with the engine possibly not fully up to temp, will shatter. Cast pistons shatter, without leaving scoring, scuffing or any other signs of piston to wall wear. Period. I have in no way shape or form have said, THIS is what happened without a doubt, but it can't be ruled out. Saying a cast piston wont shatter is pure ignorance. How many pistons have you guy's have custom made for your race engines? How many times have you cast a mold in the cylinder head chamber for a custom set of pistons? Do you flycut your own pistons? Do you guy's deck your own big DOMED pistons? Gas Port your own pistons? Have custom one-off pistons built with special ring paks and locations for ultra high end builds? Do you guy's know how we prep a set of Nascar Pistons, how we prep even the pins? You shouldn't always assume, because you have done things one way all your lives, and have never seen something happen, that it can't. Open up your minds here, we are all looking at just pictures, but you guy's need to open up your minds to understanding things exist outside of your expertise. Oh and it's Tor-S-ional , NOT Tor--T--ional.
     
  26. For those that want to talk about Torsional, and how they balance plus or minus 200 grams, this nonsense normally, I wouldn't even respond to. Please tell us about Torsional effects on a piston? What you actually should mean is " Inertia " loading and thrust, that effects pistons in this fashion shown here with the blown engine and shattered piston. If you want to discuss Torsional, please first lets talk about " resonance" and " frequency ". It would be nice to be sure you have a complete and thorough understanding here, as these topics can't be discussed without the other. Yes I've done research all my life on the topics touched on here. TR
     
  27. enloe
    Joined: May 10, 2006
    Posts: 8,726

    enloe
    Member
    from east , tn.

    Now you get to build it back faster.
     
  28. RichFox
    Joined: Dec 3, 2006
    Posts: 10,003

    RichFox
    ALLIANCE MEMBER

    I had a Howard Head 12 port GMC with some really old Jahns cast pistons of about 13 to 1 in a Bonneville car. I ran it for a few years and sold it to The Salt Circus Roadster guys. Later George called me over to his pit and #6 was just gone. Floating wrist pin in the rod with no piston anywhere to be seen. I guess it was mostly in the pan. But yes. A cast piston can shatter.
     
  29. One Finger John
    Joined: Mar 18, 2009
    Posts: 459

    One Finger John
    Member

    Time is precious for everyone, but perhaps, if you would be into it, having the machine work done and assembling the engine yourself would be something you would want to do. That way you can get to know the parts, if you have any questions about the parts you can take them to be checked, and when you are done you can take pride in a finished project.
    I know that life sometimes doesn't allow for such things but it might be worth a shot.
     
  30. BadbeatFactory
    Joined: Oct 20, 2009
    Posts: 102

    BadbeatFactory
    Member

    ...like I mentioned earlier Swade41, hope your next build works out better than before. Good luck and happy days...
     

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