I really question if the head is the fix. All cars with this type variable cam phaser system from Japanese to German use a pin that locks the phasers when the engine turns off and there’s no oil pressure. On cranking, the pin is sprung loaded and locks the sprocket to not let it wind back and push the oil out and holds the phaser where it needs to be. The Ford sprockets that are noisy all have damaged pins and it looks like a very weak stamped steel pin that’s not very strong as well as the area the pin locks into. Until they update that, you can supply all the oil you want to the phaser but all you’ll do is lessen the time it rattles but the problem is still there. I think they need to get the phaser pin issue sorted out and wonder if the late 2020’s have a different style?
No. It’s an oil flow problem.
They tried a more robust “upgraded” cam phaser as their first attempt at solving the problem. My vehicle had those installed. The tech showed me the part number was the new improved part.
They lasted about 25,000 miles.
Ford took several of the “problematic” 3.5 EB’s ( ones that had multiple cam phaser failures)
and did some extensive NDE and instrumented test runs. They installed lots of oil sending units all over the engine to monitor pressure at dozens of locations during the runs.
They found that (on these problematic engines) the oil pressure at the top front of the engine was far lower than expected.
The internal communications article I was quoted from seemed to indicate that although they never found a smoking gun, the most likely failure mode was inadequate mega-cap seal on the final cam bearing closest to the VCT phaser. The theory was that the inadequate seal was allowing too much bypass flow, which meant not enough oil flow, or pressure, to reach the VCT.
You are mostly right on your theory of operation on that mechanical pin inside the phaser, but you are missing the key piece. The reason it pops out and locks the halves of the gear together is not simply because the engine shut down. It’s because the OIL PRESSURE goes away when the engine comes to a stop.
On an engine that is working correctly, as soon as it cranks, the oil pump can get adequate flow and pressure to the top of the engine almost immediately. This oil pressure is what overrides the spring force on the pin and forces it to retract, allowing the VCT phaser to start doing it’s job.
On a problematic engine like mine, the oil flow is not getting up to the VCT quickly. Likely because of a poor seal at the mega-cap allowing far too much bypass flow.
Because of this inadequate oil pressure and flow to the VCT, the little pin stays engaged way longer than it is designed to. When it finally retracts, the engine is probably at higher rpm also. That adds up to a lot of wear and tear over thousands of starts.
And then one day you walk out to start the engine and the pin finally breaks, and your are greeted by the lovely sound of the two halves of your VCT gear slapping back and forth. The dreaded cam phaser knock.
And it is quite that sudden. Your engine may suffer from poor oil flow to the VCT for 50,000 miles and you will have no idea. Until one morning, … Knock knock knock.
Ford knows all this. They hope you don’t.
