GEN 2 Bolts shearing—High Pressure Fuel Pump

[CoronaRaptor]

Exactly. The cams are hollow to reduce weight and rotating mass, there is no inherent weakness in the design. I do not see how any cam could become “twisted”, unless they’re referring to the tone wheel shifting, which I have seen.

So is that the gear that slides onto the camshaft end? Like in this example? I'm just trying to learn what the difference is.
DAmn picture !!

 

[K223]

Exactly. The cams are hollow to reduce weight and rotating mass, there is no inherent weakness in the design. I do not see how any cam could become “twisted”, unless they’re referring to the tone wheel shifting, which I have seen.

Are these cam’s basically iron?

 

[Proflyer]

No idea guys, just reporting what I saw and what the tech saw. It ran fine for 55k, had phasers done, ran fine for 2k then popped the first pump. Replaced the pump/bolts and popped it again in less than 200 miles. I'm guessing the cam 'twisted' when the first pump popped, and then the second only held for a little bit. What's fishy is how this cam has a new part number. I'm guessing they discovered some issue with the cam that runs the HPFP and updated it (maybe made it more solid?) not sure. As to the rest of the speculation...your guess is as good as mine. Just glad to have the truck back!

 

[K223]

In the end that’s the what is important, you have your truck back. Hopefully that’s the end of that. We can reverse engineer it all day. Probably wouldn’t help you. It was up to Ford to fix it!

Enjoy that truck.

 

[FordTechOne]

So is that the gear that slides onto the camshaft end? Like in this example? I'm just trying to learn what the difference is.
DAmn picture !!

The image wasn't until I quoted your post...weird. But no, not the cam sprocket. It's a tone wheel that is pressed on to the end of the camshaft. A Variable Reluctance (VR) or Hall Effect Sensor reads the tone wheel teeth as it rotates so that the PCM knows the cam position relative to the crank.

 

[JefferyGT]

Hollow is relative. I have seen cams with only a 3-4 millimeter hole up the middle.

Also due to the type of steel materials used they are inherently brittle. They crack and break.
So this is fascinating

 

[Proflyer]

So the SA just told me Ford wanted that cam back to xray it (I assume that's how you analyze a metal part). Given that, and the updated part number, I'm thinking something is occurring to cause the failure and they know about it, and want to confirm it with each part that fails in the field. I guess if anything this thread will serve as a resource for other guys who have the same issue. Truck is running great! 250 miles or so now and no issues.

 

[Muchmore]

I still think when they go bad they hydro-lock and either twists the CAM or pushes the pump up so hard it breaks the mounting bolts or both I guess.

 

[Proflyer]

I still think when they go bad they hydro-lock and either twists the CAM or pushes the pump up so hard it breaks the mounting bolts or both I guess.

That seems to be the most probable explanation. I don't know enough about how the system works to understand what causes that to happen. Maybe the updated cam is stronger to pull through such an event.

 

[K223]

So the SA just told me Ford wanted that cam back to xray it (I assume that's how you analyze a metal part). Given that, and the updated part number, I'm thinking something is occurring to cause the failure and they know about it, and want to confirm it with each part that fails in the field. I guess if anything this thread will serve as a resource for other guys who have the same issue. Truck is running great! 250 miles or so now and no issues.

X-ray, magnaflux, sonic check, check grain patterns of the metal etc etc. They can put that part through all kinds of tests depending on what they want to find out.