What do you think caused this hole in my head?

[Burn Down]

It didn't seem sticky and I havn't really looked at the other valve seats. She gets up around 2000 degrees every pass.

You might pull the rest of the valves and check them for hanging... If you find some on this head, it only stands to reason the other head and valves are in the same condition. Might save you a more expensive repair if you whack a stuck valve with a piston.

But what do I know? I don't build competition engines... Just 250k Cat engines with enough torque to change the rotation of the earth...

 

[LBZ]

Show off!
J/K!
I've built a few 4000 series Detroits, QSK 60 Cummins and CAT 3512's back when I used to wrench full time.
Principles and diagnostic procedures are basically the same. Take your time and check everything!!

 

[MACKIN]

What's under warranty the name for your truck? Nice truck by the way. That's the first time I seen that type of a air cleaner set up if that is what that is out front on the passenger side.

 

[PureHybrid]

You might pull the rest of the valves and check them for hanging... If you find some on this head, it only stands to reason the other head and valves are in the same condition. Might save you a more expensive repair if you whack a stuck valve with a piston.

But what do I know? I don't build competition engines... Just 250k Cat engines with enough torque to change the rotation of the earth...

Pfft, I build $1M Ariel compressors :angel:

Think your little Scaterpillar has the 9000hp to turn it at full load? :roflmao:

 

[Burn Down]

Pfft, I build $1M Ariel compressors :angel:

Think your little Scaterpillar has the 9000hp to turn it at full load? :roflmao:

Horse power? Sounds like it is driven by a electric motor? What does that have to do with a hole in a cylinder head?

 

[Burn Down]

Show off!
J/K!
I've built a few 4000 series Detroits, QSK 60 Cummins and CAT 3512's back when I used to wrench full time.
Principles and diagnostic procedures are basically the same. Take your time and check everything!!

Not me Dale, Im a nobody

 

[PureHybrid]

Horse power? Sounds like it is driven by a electric motor? What does that have to do with a hole in a cylinder head?

Yes HP, sometimes electric but usually not.

You were bragging about expensive equipment, thought I would join. Is that not ok

 

[ecc_33]

i would check the whole bottom end rods, crank, mains, etc after that!

 

[JD Dave]

You might pull the rest of the valves and check them for hanging... If you find some on this head, it only stands to reason the other head and valves are in the same condition. Might save you a more expensive repair if you whack a stuck valve with a piston.

But what do I know? I don't build competition engines... Just 250k Cat engines with enough torque to change the rotation of the earth...

I agree with you and thanks for comments. That being said I have 3 pulls left and I don't have time to check the other head. The other valves seemed fine so we put the stock head back on. I don't feel 100% right doing this but it's a gamble I'm willing to take. The truck will get torn down this winter.

 

[TheBac]

Be careful Dave. Is there any way you can bring the EGTs down?

 

[JD Dave]

Be careful Dave. Is there any way you can bring the EGTs down?

Yes but it's ran the season at this level and I don't want to turn it down just yet. We have some fixes for next year hopefully. I'm hoping for the best but it is what it is. If I have any more problems that will be it. Way to much work and money for a 14 second ride down the track.

 

[Burn Down]

Yes HP, sometimes electric but usually not.

You were bragging about expensive equipment, thought I would join. Is that not ok

Pm sent... This is what whytry was getting at I think.

 

[Burn Down]

I agree with you and thanks for comments. That being said I have 3 pulls left and I don't have time to check the other head. The other valves seemed fine so we put the stock head back on. I don't feel 100% right doing this but it's a gamble I'm willing to take. The truck will get torn down this winter.

If the others felt good I would probably chance it to... 2000* would def. torch a hole in a hurry, if it found a way out of the combustion chamber un controlled.

 

[PureHybrid]

Meh, keep the heat thats where the power is :woott:

To 'add' to the thread. Whoever said something about fuel spray hitting the valve... No, just no. Simply put, I agree it was the casting showing a weak spot. I cant see from my phone, but what is behind the hole, it is the port itself or a water jacket? I ask because a crappy/excessive port job may or may not have something to do with it.

Can you run water injection? Big name pullers usually run as much water as they do fuel :roflmao:

 

[CurtisEmery]

There is a water jacket under that portion of the deck.

 

[hdd-max]

Sorry you had problems. I would have to guess a combination of a slightly skewed factory casting and really high temps. Once even a microscopic problem starts it turns into a big hole real quick with the power level you are running.

I pretty confident it wasn't just a hack port job by some idiot that built the motor. :thumb:

 

[JD Dave]

Sorry you had problems. I would have to guess a combination of a slightly skewed factory casting and really high temps. Once even a microscopic problem starts it turns into a big hole real quick with the power level you are running.

I pretty confident it wasn't just a hack port job by some idiot that built the motor. :thumb:

I'm positive it wasn't either. Lol.

 

[Leadfoot]

I'm positive it wasn't either. Lol.

I know Johnboy and others have opened up the valve guides a bit as soot tends to be an issue (especially on the exhaust valves) at the level and fueling of competition motors. It wouldn't take much for a valve to hang a SLIGHT amount and the fueling and heat to act as a torch and cause the issue you have. It could be compounded by a poor casting but at the level you are running, I think you had a good life (nothing in these motors will last "forever" when being pushed).

I would be willing to bet it was a combination of things that led to the ultimate failure, so it might take a combination of changes to "fix" it.

Good luck, you sure seem to have a very healthy running rig. :thumb:

 

[JHForman]

aluminum has a very low melting point like 1300 or something like that, its possible that the section in question got hot enough to just melt away especially if there was a crack/flaw in the original casting.

 

[Rhall]

I'm positive it wasn't either. Lol.

From the vids you've posted your truck runs lean. I'd hate to see your egts.