Piston pictures.....

GotStroke · Apr 8, 2014

I'm going to stay quiet of what I think caused it.
Let me know what you think.
Curious to see what your thoughts are.

TXlineman83 · Apr 8, 2014

I think I found your problem. Your piston is cracked. Lol. Jk. That appears to me like a stress fracture along a manufacturing defect in the piston. But I'm no Einstein. Thus I'm chiming in to learn what not to do.

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Josh@DirtyDiesels · Apr 8, 2014

Dumb question, but what is the clean looking ring around the outside of the piston? Is that normal?

TXlineman83 · Apr 8, 2014

Upon a. Closer look. Were the head or block decked. Larger cam. Seems there may have been some valve slapping to the piston top. There are little rings around the top in diff spots

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GotStroke · Apr 8, 2014

These are pictures from the tech working on it.

dzlpwr said:
Dumb question, but what is the clean looking ring around the outside of the piston? Is that normal?

I'm not sure about the ring. I'm assuming the tech cleaned the deck with the piston at TDC.

To me it looks like it may have made contact with a Valve on the right side of the pic.

forcefed6.4ford · Apr 8, 2014

I firmly believe that pistons crack due to thermal shocking resulting in stress fractures

GotStroke · Apr 8, 2014

TXlineman83 said:
Upon a. Closer look. Were the head or block decked. Larger cam. Seems there may have been some valve slapping to the piston top. There are little rings around the top in diff spots

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Stock cam, headgaskets were done 1500 miles prior, the passenger head was cracked and replaced.
This piston is cylinder 2 and driver side head was reused. i was told it was flat and didn't need decking.

GotStroke · Apr 8, 2014

Oil cooler was going bad and did headgaskets as a preventative measure. Headgaskets never blew.

forcefed6.4ford · Apr 8, 2014

All spray patterns are like that on 6.4's.

GotStroke · Apr 8, 2014

This is what I don't like

forcefed6.4ford · Apr 8, 2014

Floated a valve. When mine cracked I had no valve contact.

GotStroke · Apr 8, 2014

Too much EBP??

forcefed6.4ford · Apr 8, 2014

To float it? Possibly, or rpms.

CAT35niner · Apr 8, 2014

Looks valve contact in two spots. Then the piston fractured. Possible engine over speed with valve float.

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groove · Apr 8, 2014

Definite valve contact, however it looks like the edge of the 'lip' where the crack is appears a little melted as well. Maybe a combination?

Dzchey21 · Apr 8, 2014

what cylinders are these?

GotStroke · Apr 8, 2014

Both of are #2

GotStroke · Apr 8, 2014

It happened while on a long road trip. I was 672 miles Into the trip, and had been on cruise control for about 70-80 miles after leaving a gas station. It was dark and road was flat with very little traffic. Changed lanes to pass a semi and when I merged back over noticed a cloud/haze, figured it was dried up road salt, but noticed 100 degree higher EGTs while cruising than normal (870vs770) passed another car fairly quickly and looked at my exhaust and could see the haze coming from my exhaust. Disengaged cruise and the vibrations started...... Idk how long it was cracked to be honest. No signs other than smoke on cruise and too dark to notice when it excatly started.

Dzchey21 · Apr 8, 2014

do you have any pictures of the bottom of the cylinder head?

Looks to me like there is some melting nea0r that biggest part of the crack, i'm guessing thats where the crack started. I would be putting a new injector in that cylinder for sure.

Looks to me like you also have a back pressure issue, both valves that hit are exhaust valves. generally tho exhaust valves hit first, so it could be a combo of overspeed and back pressure.