wondering what would have caused this

[gearhead]

Wow very low mileage. It is hard to say on what actually caused it.The evidence is now gone.

[arch_stanton]

On the 3.90 being the wrong gear are they running too many rpm's, should they be running 3.50 or are you saying they too few rpm's and should have 4.11's

[Hammerhead]

(04-02-2017 )arch_stanton Wrote:  On the 3.90 being the wrong gear are they running too many rpm's, should they be running 3.50 or are you saying they too few rpm's and should have 4.11's

>60% torque load means RPM operating range is too low, should be running 4.30's or driving lessons.
That's the massive misconception with big torque motors, excessively using it is detrimental to longevity.
You're more likely to hurt a motor lugging it than you are spinning it.

[Nilao]

My avg engine load pulling heavy refer freight over the last 190k miles is 30.1%. My avg HP is 156. I run 75k pounds+ most of the time on 3.58 gears. Just to give you an idea.

[arch_stanton]

So there just not running enough RPM could fix the issue by just drop a gear or 2 while under full boost, 1600 RPM or better ?

[Signature620]

What were the actual protrusions though? This has to be an issue with protrusion, cyl head torque or some sort of contamination during the last cyl head job.

[Rawze]

You said someone replaced the head. If they were lazy and used a high-speed wire wheel on an air-grinder to clean the top of the block with the liners in place, this could have caused an issue like this. I have seen it once before. Power tools should NOT be used to clean the top of an engine block for just this reason. It only takes 0.001 - 0.002" (you cannot see this small amount) of scratching to the top edge of a liner before a problem like this will start to set in. High combustion temps will drill a hole through and widen the problem after that.

I would have first suspected this as the problem, but when you look at the pictures more closely ...

There is a clear sign of a stress-crack in the head in the valve seat at #3. It looks like there was a stress-crack in the head from the very beginning of when it was installed. Although it is now washed out by combustion gases, You can see it on the left in the picture, and how deep it was.

Where was the head purchased?

Does it have a warranty?

And was it a used/reman from a local shop machine/ head re-man shop? -- Very bad decision, NEVER re-use an ISX head if it is more than 400k miles old!, EVEN IF YOU HAVE IT RE-WORKED BY A GOOD MACHINE SHOP!! - 4 out of 5 will fail a thorough magma-flux for reasons just like this.

Those would be my first questions, because someone somewhere owes you for an entire engine now because of a bad head. -- It looks pretty clear to me that the stress crack in the head at the edge of the valve caused this.


LOOK on the drivers side of the head near the rear of it. You will find out the date of manufacture and if it was a cummins re-man or not. If it is a cummins re-man it will have an RX in the part number stamped on it. As well, if the date on the head is old (more than 3-4 months before it was replaced), it is a good bet that it WAS NOT NEW OR A CERTIFIED RE-MAN!



I am also with gearhead on this one. It is highly likely your engine block is etched and destroyed between the cylinders. Putting it back together with new head and liners could turn out to be a very risky and expensive failure. - Not worth the risk.

[linadin]

going back down to the shop will look for that info. it was suppose to be a new head from cummins. but that was the same shop that was suppose to get a new clutch 2 week earler and i already found out i payed for new but it was not new.

[Rawze]

(04-03-2017 )linadin Wrote:  going back down to the shop will look for that info. it was suppose to be a new head from cummins. but that was the same shop that was suppose to get a new clutch 2 week earler and i already found out i payed for new but it was not new.

Mr. Hag down at his shop sees about 3 or 4 engines a month with bad heads that were supposedly replaced with new by everything from mom-pop shops the stealershits where they were charged for new, but got some local re-worked POS that didn't last 200k miles.

He has one a couple weeks ago that came in from another shop that was supposedly replaced with a brand new head, and even the customer of that shop was charged for it and it said it on the paperwork. -- The DATE STAMP WAS FROM 2004~!. It was even 4 years OLDER than the engine itself!. -- AND THE HEAD WAS SLAP WORN DOWN TO THE BONE, VALVE SEATS SO HIGH THE ROCKERS WERE RIDING THE CAMS!. -- It obviously was a junk-yard head off an old engine that someone tried to re-work.

Here is a pic from it ...

It seems to be a regular problem with shops ripping people off and skimping on parts and workmanship these days. It is sad to see. Not only does this cause problems with the valve train, but it also causes combustion and compression problems too.