Ford’s lock action seems to be somewhat secondary to overall oil pressure. When pressure is dropped on engine shutdown, that bias spring that you can see on the outside of the phaser, pushes the cam towards the middle, and the lack of oil pressure allows the pin to fall into the hole under the pin’s spring force. There is a bit more to it I know. There is oil control to the locking pin on one of the rotor leafs. So programming can help by controlling angles before engine shutdown.
Essentially that is correct, but on shutdown the oil in the phaser does not drain back immediately. That is why a sprocket with a failed locking mechanism only rattles after a cold soak, and not after auto start/stop events or between warm starts.
I see also that the HL3Z-***-CD backing plate has a redesigned locking hole which looks as though it would improve the ability to unlock the pin at lower pressures. Old is on the left. New is on the right in the included pictures.
One of things I’ve noticed in pictures of newly failed phasers (ones that have not been allowed to rattle for 10k miles) is the hole that the pin is meant to lock into is worn in a very specific pattern. It’s only on the side furthest from the filling channel. The opposite side is pristine. (Shown in the left picture). There’s an erosion that is deepest at the location that once was the rim of the hole. How did that erosion develop…. Suppose at least some of the time, the lock pin doesn’t make it into the hole, because the parking spring is not quite strong enough to overcome an opening intake or exhaust valve when the engine just comes to rest. Now we restart the engine. The cam sprocket moves rapidly carrying the pin to the hole, but the camshaft doesn’t move at all until that pin slams into the far side of the hole. Just a little material excavation ensues. Repeat that over and over. That may not be what happens. Another possibility... Suppose on engine stop the pin does make it into the hole but in order to seat, it has to displace oil which takes time. Then suppose that infernal auto start/stop kicks right back in with the pin just barely seated. Same thing…one side of the hole takes a hit. Or perhaps another possibility is the pin is just not unlocked enough at idle or low pressure situations and the pin bangs on the rim of the hole. Although I’d expect that to be more symmetric wear.
The programming changes VCT duty cycle while the engine is running. The prior calibration was running the VCT units near the locking cavity threshold. That resulted in wear between the pin and cavity, which is the tapered wear pattern seen in your picture. To your point about keeping the locking pin in the fully unlocked position at idle, the new calibration increases oil pressure at idle for that reason.
I could see where update 21b10 makes things better for phasers that have not yet developed a problem. And I might even be able to see how it makes things worse for phasers that have.
Since it prevents wear from developing, it is critical to longevity for both the prior and current parts.
I’m curious; is the ML3Z-*** part better than the HL3Z-***-CD? Some seem to think so. I have my doubts based on these pictures and the wording of the #3 and #4 supplements
They’re the same internally. People started rumors about that because they appear different; the only reason for the appearance difference was a change in supplier.
