I'm currently changing a camshaft and have seen lots of advice on resetting the VVT sprocket, but I'm still confused. Mine was locked after i mated the sprocket to the shaft, so I've actually dismantled it like this https://www.mr2roc.org/forum/index.php?topic=56202.msg649151#msg649151
and reassembled it unlocked. Now I think I have to lock it before reinstalling the camshaft. But I don't understand why I've done all this!? Could I just have left it as it was?
Yes. you could.
Thanks Carolyn! I followed the instructions in the technical manual hoping the reasoning would become clear, but by the end I thought I was going mad.
Changing my VVT actuator in October, it's come delivered in the lock position. I really don't get the importance of the whole lock / unlock thing if you're locking it before install anyway. The MrT instructions are very explicit on the need for it... does it not unlock properly on the camshaft if it was locked on install, or does it really not matter?
I think that the reset procedure ensures that you haven't somehow jammed the locking pin in a funny position when you bolt it to the camshaft. If I did it again I would just be careful when I assembled it and assume it works. I think you would have to be pretty inept to get it wrong. The Toyota instructions are confusing though.
I did dismantle one of these a couple of years ago to see how it all worked inside. You do have to do some locking and unlocking if you're going to dismantle and work on the hub.
I really don't think you have to worry as long as it is locked in the start position when it's installed. If the the oil-ways in the head are clear, it will unlock when oil pressure arrives.
Just check that the two lines on the hub are lined up - then it's ready to go.