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gondola993 (Electrical) (OP)
16 May 12 23:04
What can you guys tell me about the failure mode of this head gasket. It's from a Cummins 8.9L 6 cylinder diesel, ISL. The number 6 cylinder developed a breach of the firing ring near the outer two head bolts. We've seeing a pattern of these failures. I don't know if it's a head gasket issue, or something else (head bolt adequacy or torque, liner height, cylinder head defect, or something else). Any help is very much appreciated. Thanks, David
hydromarine (Mechanical)
17 May 12 5:34
You need to do your checks , cylinder head flatness , bolt/nut torque sequence, the pattern on the gasket suggests to me a warped head or uneven tightening of the cylinder head ... but could be anyone of the things .Check the cylinder head for flatness first , use new studs/bolts nuts for this cylinder on re-assembly .....ensure head casket is perfectly lined up before assembly .
Pancholin (Automotive)
17 May 12 10:36
To me the photo of the gasket suggests that it was damaged either prior or during installation. The clamped surface looks straight but the gasket is pushed out at the rear as if it were hanging on a nail and pulled off. Suggestion: Cut the heads off the old studs/bolts and use them as guide pins when installing the obviously heavy head.
Tmoose (Mechanical)
17 May 12 12:50
Are the failures on factory built engines, or repaired? Is there a maintenance head re-torque prescribed by Cummins?
gondola993 (Electrical) (OP)
17 May 12 14:03
Thanks everyone.

Pancholin, Those are my thoughts too. I'm thinking the engine was assembled that way. It's hard to imagine a defective head gasket shifting at runtime overcoming the clamping force of the head.

Tmoose, The engine failures occur at around 1000 to 2000 hours. They're new factory built engines - built in 2003 and 2004. No spec for head bolt re-torque.

dicer (Automotive)
18 May 12 13:41
At first glance the gasket looks like some cheapy thing used on a gas engine. My first inclination is
to suspect the gasket as something made offshore, ie not good quality. You mention liners, have you checked protrusion? Since alot of things are no longer made where they should be, there are a lot of problems with substandard parts, the bolts could also be an offshore part with questionable quality.
After checking the obvious as mentioned by others, contact a reputable gasket manufacture that makes their own product and doesn't sub it out to say china.
patprimmer (Publican)
18 May 12 19:46

Quote (dicer)

My first inclination is to suspect the gasket as something made offshore, ie not good quality.

Does this mean that if he lives in China goods from the USA will be cheap crap?

Does it mean that if he lives in the USA goods from Germany, or Sweden or France or Japan etc etc are cheap crap.

All I see is a typically blown head gasket with zero indication as to the cause. It could be anything from inadequate clamping force for any number of reasons to corrosion to incorrect surface finishes to inadequate structural integrity to an overheated engine to an engine that was subjected to some hydraulic lock. Frankly with the lack of info on any part except the gasket itself any comment as to the cause is wild speculation.

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gondola993 (Electrical) (OP)
18 May 12 23:47
Speculate for me a little Pat. I'm not an Automotive or a a Mechanical or a Publican. :) What's your best guess? Do you think it was built this way or is it possible that the engine blew the gasket out over time?

patprimmer (Publican)
19 May 12 2:34
I really can't guess without seeing and measuring the block deck, the sleeve heights, signs that the sleeves might sink as the head is tightened, condition of threads, stretch in bolts and condition of the area around the bolt holes where the heads of the bolts seat, the depths of the dowels vs the dowel holes, signs that coolant flow might have been obstructed or heat transfer impeded etc etc etc. All I see is a blown gasket that looks like most other blown composite gaskets I ever saw.

Are the deck surfaces flat? Do they have a slightly coarse surface to grip that type of gasket? Are there any signs of bolt stretch or fretting under the head as a result of loose bolts? Are their deposits of corrosion or solidified water impurities in the water jackets near the blow point? Is it an OEM gasket or a replacement? If a replacement, is it from a known good supplier no matter where it's made? Are their any signs of water laying in the cylinder apart from what might have come from a leaky gasket? I know, hard to tell? What was the engine used in/for? Semi trailer tractor, farm equipment, marine, RV, serious off road, mines, stationary? If it is not an OEM gasket is it a different type to the OEM, ie is the OEM multi layer metal shim rather than composite? is the OEM SS sheathing of the built in O ring where this is not SS? If corrosion may have played a part, is an SS sheathed gasket available?

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dicer (Automotive)
19 May 12 3:50
Off shore is USA speak for made in china. It is a huge problem.
patprimmer (Publican)
19 May 12 6:26
I know the prejudice built into that particular USA speak, well at least among the more ignorant citizens.

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NickJ67 (Mechanical)
19 May 12 15:35
I'm with Pancholin on this.

That rear gasket edge shows signs of damage prior to being clamped down. There is a straight witness mark showing the clamp line of the head, but a section of the gasket is pushed well out and looks like it has been that way for some time judging by the dirt on the protruding section outside the clamping line. The only problem I have with this theory is I can't see it doing anything like 1000 hours like that......

Other than that, it's quite a thin section of head/block at the back (maybe the scale is deceiving) and I'd certainly be checking carefully for flatness before reassembly with good quality gasket and correct torques/tightening sequence.

dicer (Automotive)
20 May 12 22:49
Its based on facts. And no prejudice here at all. Facts like the huge tire fiasco years back, the poisoned pet food, the antifreeze in toothpaste, and lots of other not so well known publicly, cases of failures of outsourced parts in the aircraft and automotive world. They have done this to themselves, with no concern for quality. I suppose its the way the workers are treated as well. So I would say my speak is based on knowledge not ignorance. We the citizens are the ones that get stuck with the problems after purchasing substandard junk, cause it usually ends up in the trash. That country has no concern about warranties, they know the middle man won't pay the shipping costs to return it. So in all cases the outsourcing company eats all the litigation costs etc for the part failure if it results in harm to someone. If the failed part is metal it will go back to china in a scrap ship.
patprimmer (Publican)
21 May 12 5:10
Like I said. Prejudice and ignorant and wrong.

I have also occasionally bough complete garbage that was made in the USA.

I have also bought junk that was made in the UK, Germany and France and even Japan.

I have bought junk made in China. I have also bought very suitable good quality product made in China and toured an electronics manufacturing factory that was indistinguishable from a Japanese one.

I bought an Isuzu 4WD a few years ago in the belief it was made in Japan. Turns out it was made in Illinois and was the second lowest quality car I ever owned. Sadly the worst was an EA Falcon which was made in Aus.

The US auto industry basically went broke and needed major government bail outs because their quality was not up to world stds.

I currently have some Chinese tyres on my car and they are first class.

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swall (Materials)
21 May 12 15:50
Ford did not go broke; no government bailout required. In the case of GM and Chrysler, I would say they went broke because their costs were too high.
patprimmer (Publican)
21 May 12 19:47
Well American cars sure don't sell well outside the USA. There is a reason.

My point is it is narrow minded bigotry to presume everything made in the USA is better than anything made outside the USA. It is just not true.

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IRstuff (Aerospace)
21 May 12 20:04
We Americans have rather short memories and inflated opinions about ourselves. The fact of the matter is that companies like Toyota, Datsun (Nissan), and Honda were kicking the butts of the Big3 in the late 70s and 80s on quality AND price. It was only the Japanese's financial bubble that burst in the early 90s that gave the Big3 a chance to regroup and rebuild.

And, it's not really that American quality has increased, although that does appear to be the case, it's more than the Japanese quality has deteriorated because they've become infected with the same sort of laziness and lack of attention to detail that epitomized the American auto industry 30 yrs ago. Not to mention THEY'RE outsourcing as well.

China is about where Japan was in the 60s, when the Japanese were flooding the US with cheap, transistor radios. But, they built on that foundation and moved up and improved. I don't think that either the US or China will ever have the single-mindedness that was Japan. The fact that the majority of the US engineers on this site denigrate and heap contempt on Deming's concepts and 6-sigma is an interesting irony, since some of them think that US quality is high. Guess what, those guys at those companies likewise heap scorn and contempt on DFM. And there's nothing new there, the same guys heaped scorn on DFM when it was first introduced more than 30 yrs ago.

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Helpful Member!  patprimmer (Publican)
21 May 12 20:30
And I am sorry if I offend some of you. I am not having a go at Americans. I am having a go at one particular comment by one particular individual who makes a habit of making sweeping and inaccurate generalisations.

All nations consist of a collection of individuals and each individual has his own skills and talents. Sure conduct is influenced by the environment, but there is still a broad range of conduct within any environment or culture.

I know China still produces a lot of low quality product, but it is not an absolute law. They do produce some very good product.

I also know that the USA produces some very good stuff, but they also produce some junk.

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crerus75 (Automotive)
23 May 12 12:11
I can add one piece of anecdotal evidence (and I use the term loosely):

Back a few years ago, Chrysler had a problem with composite head gaskets on some of their 4 cylinder engines as fitted to Neons, etc. The cam sensor, located at the rear of the engine, would leak oil down the head and onto the gasket. This would weaken the gasket in that area (same area as shown in your photo) and eventually cause a blowout similar in appearance to what you're seeing. The replacement gasket was MLS and solved the problem. Not saying that is your issue, but since you have everything apart you might want to look for sources of external contamination.

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