Ya'll Are Amazing, But I'm Not So Much... VVT Clarification

[Stork]

edited for focus

From the 200,000 miles tune up thread
viewtopic.php?t=92790&start=100

Correct - full advance is where your T-belt sat.

NO (not shouting, just emphasizing) do not torque with t-belt on. Torque on exhaust hub is done with cams still locked, belt NOT on.

The idea is you get the exhaust hub as close to spot-on w/full advance mark on valve cover, then cinch down snug. You always rotate the hub CLOCKWISE until you approach the advanced timing mark. I stop just a 1-2mm before I get to the advance mark. Cinch down, then rotate CCW to verify retard mark is also on. If so, then torque T55 to 88 ft/lb.

If the marks don’t line up perfectly after torquing, it’s ok. This is why the holes for the sprocket are slotted so you can fine tune after torquing. Speaking of slotted holes, try to have your threaded hub holes “centered” in the middle of the slots.

TL/DR
If I am reading this correctly,
* VVT Hub is snugged to the cam it will be approximately 1 or 2 teeth before the mark on the upper cover (in the F250 write up, it mentions 1'oclock. Thinking that was a typo, I presumed 11'oclock)

* when installing the belt, the VVT hub will need to be preloaded/ rotated clockwise/ rotated forward to its forward, most advanced position and this is what lines up with the upper cover. Relax the tension with the belt off, it goes to its full retard position. Most advanced will correspond with the cover. Adjust the outer ring gear as need to align mark if slightly off while avoiding either limit of the slots/ ovals

* The VVT hub, when in the most advanced position, should not rotate beyond the upper cover mark

Is this correct?

... and thank you for your time on yet another confused soul

[Stork]

Vida Cam Values


Out of concern I scoped the combustion chamber and we're looking good valve-to-piston contact wise. My post is short of doing the math, as some have discussed, to calculate degrees manually and in hopes of keeping the lack of valve-to-piston contact theme

[jonesg]

It would be easier to read if you said who "they" are.
Junkyard? auto repair shop?

"they" still need this vehicle ? so it belongs to someone else ?

What caught my eye is the cam hub bolt being on the loose side, its supposed to be very tight, like a lugnut tight.
I think it was 93 ft lb or more.
The cover cap is nowhere near as tight.

That being true, I'd do a compression check before wasting any more time fighting with it.

[Stork]

It would be easier to read if you said who "they" are.
Junkyard? auto repair shop?

"they" still need this vehicle ? so it belongs to someone else ?

What caught my eye is the cam hub bolt being on the loose side, its supposed to be very tight, like a lugnut tight.
I think it was 93 ft lb or more.
The cover cap is nowhere near as tight.

That being true, I'd do a compression check before wasting any more time fighting with it.

I appreciate the feedback. Owner is an international student on a fixed income

[abscate]

If the engine was run with the internal cam bolt loose, that’s bad. Compression test in order. There is no way the outer cam cover bolt loosened the internal one, it must have already been loose.

The cam flank angles showing 20 degrees is indicative of them being stuck at full flank, which is what happens if the pulley isn’t in the right place.

[Stork]

If the engine was run with the internal cam bolt loose, that’s bad. Compression test in order. There is no way the outer cam cover bolt loosened the internal one, it must have already been loose.

The cam flank angles showing 20 degrees is indicative of them being stuck at full flank, which is what happens if the pulley isn’t in the right place.

Thanks for the info and I was surprised as well. Thought I snapped the cam somehow, but thankfully no. Definitely going to do a compression test after I get it back together. Editing to focus on current issue.

[jonesg]

edited for focus

From the 200,000 miles tune up thread
viewtopic.php?t=92790&start=100

Correct - full advance is where your T-belt sat.

NO (not shouting, just emphasizing) do not torque with t-belt on. Torque on exhaust hub is done with cams still locked, belt NOT on.

The idea is you get the exhaust hub as close to spot-on w/full advance mark on valve cover, then cinch down snug. You always rotate the hub CLOCKWISE until you approach the advanced timing mark. I stop just a 1-2mm before I get to the advance mark. Cinch down, then rotate CCW to verify retard mark is also on. If so, then torque T55 to 88 ft/lb.

If the marks don’t line up perfectly after torquing, it’s ok. This is why the holes for the sprocket are slotted so you can fine tune after torquing. Speaking of slotted holes, try to have your threaded hub holes “centered” in the middle of the slots.

TL/DR
If I am reading this correctly,
* VVT Hub is snugged to the cam it will be approximately 1 or 2 teeth before the mark on the upper cover (in the F250 write up, it mentions 1'oclock. Thinking that was a typo, I presumed 11'oclock)

* when installing the belt, the VVT hub will need to be preloaded/ rotated clockwise/ rotated forward to its forward, most advanced position and this is what lines up with the upper cover. Relax the tension with the belt off, it goes to its full retard position. Most advanced will correspond with the cover. Adjust the outer ring gear as need to align mark if slightly off while avoiding either limit of the slots/ ovals

* The VVT hub, when in the most advanced position, should not rotate beyond the upper cover mark

Is this correct?

... and thank you for your time on yet another confused soul

So it really looks like it was running ok but the cam hub slipped because they forgot to torque it after setting it up.
Which means it should still be fairly close.

this video helped me, but you're working with the unknown , going over someone elses work which might be wrong so...

I believe if the crank is on mark and cam lock is in proper orientation then yeh the cvvt hub deflection will be approx 2 teeth duration. You can clearly see the amount of deflection in the video. If the outer sprocket ring was not touched and it ran fine initially.. it should be good as it is.

[cleven]

I’m learning so much coming from the P80 to P2 platform. Sure not an easy transaction but reading these post makes it understanding.

[SVO LOU]

Just found this video and prefer it to the above one.
https://youtu.be/Cu-MjTNv7lM

[abscate]

One of our P80 wankers wrote up a decent cam flank thread in April 2020, if you search that Forum for “ cam flank” it should be findable