VCT problem on 5.4lt triton
 

i got 1 in my shop thats having the same issue.ive done 50 or so of these and havnt ever been kicked around like this.new phasers and chains and tensiners and have codes p0012 and p0021.its starting to make me mad.each time i tear back into it the timings off both cams.im gonna try removing all the followers and retiming the engine and crank it over without the plugs in it to prime the hydralic tensioners to see if the problem is the chains jumping with no oil pressure to them.just to let you know this teruck has been in 4 diff. shops and im stuck with it.ive subed new actuatior solinoids and a pcm for the issue because i hadnt rechecked my timing on the cams.ill let you know how mine turns out.hop[e you let me know how yours ends up.

I started my truck this morning, and it idles perfect, probably becasue over the weekend i lost the residual pressure in the VCT, and as soon as i touch the gas pedal it runs rough. Thats what boggals me the most is that it idles perfect after sitting for a awhile. any ideas on that on?? thanx

the vct system dosnt start to function until 4000 rpm or the second start up.i found that a prior shop had installed 2 left hand hyd. tensioners and both seals on them where cut.and i also had 1 that had collapsed completely.i ended up pulling all followers off and installed new tensioners.i spun the engine over to prime the system and they have heald in place and havnt jumped time.im in the proses of working on a few other vehicles and havnt had time to reinstll the fallowers and valve covers to see if it lives.ill let you know.

I'm not a engine builder but I've been reading all I can on these modular engines and have found out that you should "degree the cams". Would this make a difference?

i havnt gotten into the degreeing part of the triton engine yet,i assume its more for the performance/racing crowed.these engines have a mark on the cam phaser and the crank gear.this is where you line them up and dont have any other place to go.if they are out of time buy 1 tooth thenn the pcm will set a code for the vct over advanced/retarded,depending on which way the chain jumped.im sure in a performance area that the pcm can be tuned around this issue.

I'm just courious but, when you rebuild these 4.6's are you finding that you have to hold to the "extreme" tight tolerances that ford requires?
You know, cylinder wall to piston clearance .0005-.001 or .002 wall taper etc?
I don't even know how you can hold to these tolerances unless you use a tool die and mold shop to "edm".

Again, I'm no expert but my manual not only preaches about the timing marks but says to keep the cam "key" centerline perpendicular to the top of the head.
It shows this diagram in the manual many times with the timing marks.
I would think that if you keep the timing marks lined up correctly the cam key cl's would be lined up automatically????
It also says to use "ford oem" align tools. Cam holder and cam turning tool.
Lets us know.

Those are not necessary unless you're doing a single cylinder head repair/change in-vehicle and do not wish to disturb the cam timing or retime both cams post repair. They're simply to assist factory techs and shops in saving labor time on repairs.
JL

Here comes the stupid quesition.
What is "VCT"??

Variable
Cam
Timing

JL