GEN 2 Bolts shearing—High Pressure Fuel Pump

[TwizzleStix]

Definitely sounds fishy to me. How were the camshafts determined that they were "twisted"? Was the casting cracked? If not, it's a scam. Casting don't twist or bend without tell-tale cracks. Maybe the camshaft position reluctor that provided cam position to the ECU was not installed correctly, or it could have "slipped" position if pried upon. Until there is real proof presented, I call ********.

 

[isis]

Definitely sounds fishy to me. How were the camshafts determined that they were "twisted"? Was the casting cracked? If not, it's a scam. Casting don't twist or bend without tell-tale cracks. Maybe the camshaft position reluctor that provided cam position to the ECU was not installed correctly, or it could have "slipped" position if pried upon. Until there is real proof presented, I call ********.

I don’t think these cams are a single piece of cast metal. That’s why it can happen.

 

[TwizzleStix]

I don’t think these cams are a single piece of cast metal. That’s why it can happen.

The camshaft itself and the lobes for each valve is cast as a single piece. The lobes for the valves, lobes for the HPFP and the round surface for the position reluctors press-fit are machine finished from the original rough casting. The position reluctors that provide positioning signals are pressed onto the finished casting as they must be precision aligned and can't be cast into place.

 

[Muchmore]

Maybe when these pumps go bad they hydro lock and twist the cam as it tries to rotate.

 

[EricM]

And at some point the bolts say **** it- I'm done twisting the cam.

 

[isis]

The camshaft itself and the lobes for each valve is cast as a single piece. The lobes for the valves, lobes for the HPFP and the round surface for the position reluctors press-fit are machine finished from the original rough casting. The position reluctors that provide positioning signals are pressed onto the finished casting as they must be precision aligned and can't be cast into place.

So what part of that means that something can’t be twisted? Once I knew it wasn’t the one piece thing that most cars have, I’m out of my element. Maybe ‘the cam is twisted’ just means one of those other pieces has let loose? Is that super out of the question too?

 

[CoronaRaptor]

We need pics of this twisted cam or of a cam for these engines, i've never heard of hollow cams. FOund this pic, I think this is one.

 

[Jakenbake]

Round shapes, even hollow shapes, traditionally handle torsion pretty well. The wild card is something that is in rotation and then abruptly stops or at least hits a large resistance to the rotation.

Good info in this thread. Looking forward to seeing if anyone gets to the bottom of this.
Glad OP’s truck is back home.

 

[TwizzleStix]

MANY camshafts are hollow ground. Only the old-school engines built before ~1990 have solid camshaft castings. There's nothing new under the sun. The ONLY item on the camshaft that can "move" (rotate) in relation to the camshaft drive gear position is the cam position reluctor(s).

 

[FordTechOne]

MANY camshafts are hollow ground. Only the old-school engines built before ~1990 have solid camshaft castings. There's nothing new under the sun. The ONLY item on the camshaft that can "move" (rotate) in relation to the camshaft drive gear position is the cam position reluctor(s).

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.