What has to be removed to replace valve seals

[Pozobyt]

And do I have to reset timing? because I have no idea how to do that.

 

[mazda-man]

You have to remove the cams so you can remove the rockers and then the valve springs. I have heard of some people changing cams out without removing the timing belt completely and it involved ziptieing the belt to the cam gears but I have never tried it I have always just removed everything and then retimed everything. If you are removing the head to do the job I highly recommend sending it to the machine shop to check it out and you might just want to have them replace the seals while they have it. My local shop only charged me $140 to pressure check, resurface my head and replace the valve seals. I provided them with the seals. Then you also have a warranty for a certain period if you have a seal problem.

 

[BogusSVO]

your best bet is to re-set the time belt.. if anything moves while the belt is loose you stand a chance of bending valves

so the cams need to be removed, if your doing this on the car, then you need to have some way to hold the valves up, compressed air in the cylinder or the string method

also you will need a tool to remove the valve locks, then reinstall them.

 

[El Cuervo]

I honesty recommend doing using the rope method. But thats just me.
Raise car on jacks. Remove negative battery terminal cable. Remove driver side tire. On the 1g support motor with jack under oil pan using some cardboard so you don't damage your pan. (don't know about 2g). Remove valve cover. Remove timing belt cover(s) unbolt cam sprokets, remove timing belt, remove cam sprokets, remove cam caps starting fromt the middle and working you way out. Number them or marke them in a way that you will remember how to put them back exactly how they were. There is this spring compressor that you can purchase. It bolts to the head and allows you to compress the springs. Head on block valve stem seal replacement
Follow the above link and read through both parts.
I'd suggest doing your timing belt if you haven't done so.

Good luck.

Oh sorry, I didn't notice you were N/t. Then desrigard some of the stuff that I said.

Sorry.