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VVT sprocket unlocking procedure with pics.

122K views 90 replies 23 participants last post by  Scuderia2ZZ 
#1 · (Edited by Moderator)
So you wanna change your cams and play with the big boys or have some time to waste and feel some sudden love towards your stock cams? :hit:
Every time you remove the VVT sprocket, you must go through this procedure. If you don't do it this way, you run the chance of wedging the pin tight....thus making the VVT inoperable. No vvt = no optimum power at all RPMs!
There's a TSB about this...I have tried it, and it is hard to do, especially on a new sprocket + with their way, you have no leverage(the cam) to turn it while it gets unlocked by the air pressure.

I won't go through the valve cover removal, and all the rest as this is obvious....and if it's not to you, stick to the appearance sections and have the job done by someone with a bit more experience.


You have replaced the cam and are ready to bolt up the VVT sprocket.
This is what it looks like:

That's the hole you're going to blow some air into(there's another one on the other side, don't worry about it. We're going to use the other one).
Reinstall and tighten the bolt that holds the VVT sprocket.... by hand.

Get some electrical tape and start taping ....crisscrossing it until you have covered all the holes except the one you're going to blow some air through.
You might want to clean the part with a bit of solvent beforehand so the tape sticks and makes a better seal.


If you're reusing your old VVT wear some glasses and take a rag to cover the sprocket....there's still plenty of oil in there....ask me how I know.:eek::

Now you're ready to unlock it:

It helps to have an extra pair of hands for this part, but it's doable by yourself. Now start blowing some air (about 20 PSI worth of it)and turn COUNTERCLOCKWISE. Sometimes it takes a couple of shots... work at it back and forth until you feel it unlocking and moving.
To give you an idea of how much movement was talking about, I marked it with some tape:



Keep it fully turned(unlocked) and tighten the bolt that holds the VVT sprocket to the cam to 40 ft-lbs.
Then you can lock it back in place(clockwise) before reinstalling it on the head.
Voila.....;)

PS: If you spot any mistakes, feel free to point them out.
 
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#43 ·
well i bought it becouse mr T ****ed up mounting a new clutch clutch plate from toyota bad assembly after a week pushing the 2 gear blew the tranny sky high transmission case was cracked and they assumed the responsability i bought the complete C-one gears and final gear and and did not payed toyota for the labor or the new tranny case , the gear are alot stronger the car does push alot better specialy if you do track whith alot of corners the car is alot more responsive also i put it in sincros from celica that runed in the nationals from mr T competion division in spain they told me that they are diferent diferent material the color is diferent , i still can get them if any one want , the shift
 
#47 ·
resuming the car had the VVT working and now it does not :bang::bang::bang
:bang::bang::bang::bang::bang::bang::bang:
 
#48 ·
oh, that's bad! Why do you said your VVT is no longer working ?

What EMS say is wrong, it's the exact opposite. Initially, it's possible that your vvt was not locked even though you did not follow the procedure. You were just lucky apparently! Now, if you followed the procedure, it should be fine.
 
#49 ·
i realized that i rotated the cam to the LEFT not the sprocket
 
#50 ·
Ive been trying for 3 days now to unlock the sprocket with no luck. Can anyone give me another pointers? Ive followed this step by step but the sprocket wont move...I also perform the same steps with the old sprocket with no luck...is there an easier way or another stuff I can try?
 
#51 ·
The only other way is to open it with vice grips and unlock the pin .. but I DONT RECOMMEND THAT.

I'd just check that your tape does not leak air. Being 2 people also helps (one shooting air and one turning the sprocket). It sometimes takes a few trials. Good luck!
 
#52 ·
For those who want to see the VVT-i in the flesh...er metal:


Front plate removed. The VVT-i is in the locked position (maximum retardation).


Spring in lock pin.


Lock pin in lock orifice in the sprocket plate.


Sprocket plate.
 
#54 ·
My first experience with unlocking the VVT sprocket was unsuccessful like yours. What made the difference was going to a different air gun. I found the closest thing I could find to Many's gun in his pictures and that did it. I found a Kobalt with the smallest tip of all I had seen. Also, I was really surprised how it felt to unlock the sprocket(i.e. how it felt unlocking and then turning), so make sure that you're not missing something.
 
#55 ·
i talked to toyota and mecanics told me that The VVT locks

but it does not need to be unlocked becouse automatic when you start the engine the oil pressure unlocks it does not matter , if for some reason it stays locked not normal the system is malfuctioning , they told me that there is no unlocking or locking procedure locks and unlocks by oil pressure
 
#63 ·
I hope for you that those dudes are not the same that work on your car, cause they don't know $hit.

It's funny how sometimes you learn the mechanics at the dealer something that you actually found ... in TOYOTA repair manual.
 
#56 ·
Those mechanics you talked to don't know what they are talking about. Tell them to look it up in the Toyota repair manual. There is a passage that clearly states that the gear needs to be installed on the cam in the unlocked position and then turned to lock. It's a safety procedure Toyota put in place, the reason for that is that it can potentially seize locked when torqued down because of pressure of the vane assembly on the lockpin.
 
#64 ·
Eariler today, tried masking / taping up the holes, then firing pressurised air into the cam hole and no movement........... then I thought this top bolt on the top of the sprocket, sod it will undo and guess what the sproket comes off from the cam, see pic below. The cam location spigot was at the top left postion not in either of the other opposing horizontal postions, so is it just a matter of putting the new cam location spigot in the same postion and not fathing around with this locking procedure, and just tighten the bolt then reinsert back into the engine???...

There is no way by firing air into the cam will the sprocket be taken off unless you undo and take off that top nut to swap from the old to new cams.
I'm just a little unclear about this can somone please clear this up for me.

 
#65 ·
short and sweet, i didnt even have to use tape.

put vvti intake gear on cam, tighten the bolt by hand.
that hole on the camshaft right before the gear as ^^^ is where you put air in.
I used my hands (fingers) to cover the holes and had someone put the air in the hole
as the air is being pressurized alot of oil will spray out and you should be able to rotate the gear back and forward like an inch or so. Move it all the (if you have camshaft against you and gear away from you) to the left.
Once you know it moved all the way torque it down.

and your done :D
 
#66 ·
But why do you have to use the air???, mine came out of the 11 O-clock hole posion, and the new cam went back int he same position on the sprocket so the paint marks would align up again, both times the VVTI sprocket was solid , no play. IF I fire the air in again and make a air tight seal and it turns to the left then the "paint" markings will be out from previous setting <shrug>
 
#67 ·
no no no, im not sure but i think you have to forget the paint marks since you removed the cam gear bc yeah when you force air into the oil channels to unlock the gear it will move a bit its with the air pressure the vvti gear "moves" to retard or advance timing. You just turn it to unlock it, then tighten the bolt, then you turn it back so the marks dont move. you move it left let say to unlock it then onced its nice and tight on there you turn it back
 
#68 · (Edited)
The air is simply to unlock the sprocket so that the VVT-i mechanism moves freely. See my post with the pictures. The air is to push the lockpin back up out of the lock hole in the sprocket plate so that the cam gear (and internal vvt-i vanes) can rotate independent of the toothed sprocket.
Removing the whole assembly from the cam is not the issue, for that you just remove the center bolt. The issue is that when installing the cam gear back on the cam, if you torque it down with the lockpin engaged in the hole (hence called locked position), there is a slight chance that the whole mechanism will seize against the lockpin and sprocket plate, preventing the lockpin from being pushed by oil pressure and unlocked so that the VVT-i can operate normally.
It's mostly a safety precaution, some people have removed and reinstalled their camgears locked and it still worked ok, while others have done the same and had the thing stay locked.

The correct procedure is to install the camgear on the cam in the unlocked position (vanes being able to move a little both ways), torque the center bolt to spec on the cam and after that turn the camgear clockwise to lock the pin inside the sprocket plate and then install the cams in the engine. The paint marks don't matter cuz the assembly has to be locked anyways after being torqued on the cam.
 
#70 ·
it didnt move when i did it with a torque wrench, it stays still but if its moving just use a rag or something or sit and put it in your lap lol
 
#75 ·
100psi you cant lose
 
#76 ·
ok i think i got it right.
1.removed old sprocket from old cam.
2.install the sprocket on new cam.
3.use the bolt and hand tight.
4.tape up holes and blow air in it till it unlocks.
5.make sure its unlock, move left to right easy.
6.torque bolt to 40 ft-lbs.
7.lock the cam again.
did i do this wrong or right?
 
#81 ·
Thank you for this. Apparently this is to remove the chance of the tightening of the bolt causing the locking pin to be pinched and not move at all.

ok i think i got it right.
1.removed old sprocket from old cam.
2.install the sprocket on new cam.
3.use the bolt and hand tight.
4.tape up holes and blow air in it till it unlocks.
5.make sure its unlock, move left to right easily (do not relock).
6.torque bolt to 40 ft-lbs.
7.lock the cam again clockwise and install into head.
did i do this wrong or right?
 
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