Hey guys I wanted to ask for advice before doing this as I am not 100% on what I should do. I want it to be as reliable as possible of course and money isn't a problem however if I don't have to spend a lot I would rather save for other things.

I am gonna be installing new upgraded valve springs + retainers and the stage 1 comp cams from zzp. I am getting gaskets, and new cam o rings. I got my intake valves walnut blasted and one of my cylinders was leaky and it was seen as possibly the valves weren't seating properly. I noticed since then its been much improved and ran a compression test with steady numbers in all cylinders but haven't done a leak down test again since. I was debating buying either a whole new head that comes assembled with the valves and such and then installing my upgrades but if I wanted to reuse my head can I just replace the valves and valve seals? or should I replace everything while in there (rocker arms, lash adjusters). And is it recommended to get my head machined by a shop? I haven't looked inside yet so I don't know what to expect and when I got the timing done last year the shop that did that said everything looked ok inside.

Lastly when I did my timing about 25,000 kms ago the kit didn't come with new cam phasers. Are those usually good to run or do they end up needing to be replaced?

Edit: After pricing a new head from ZZP with what I need I think that'll run me a lot cheaper and include everything new vs trying to machine my head and replace components. Then I can try to resell my used head for something to cover the costs. Still let me know what you guys think though!

 

Imho if you are reusing your cyl head, I would do the whole thing for peace of mind. You may not need to but since you have everything apart any way?

Last summer there was a buzzing sounds that I have no idea what it was. Thought it was a loose heat shield? Ended up rebuilding my alternator bearing and replacing the turbo journal bearings. Not it.
Since I still have the original timing chain. I had John replaced all the parts in timing chain assembly including the phazers and he suggested to do the harmonic pulley as well. They all looks fine with 110k kms. Buzzing is gone. Weird ?? lol

btw. if you haven't replaced your 2 O2 sensors in many kilometers, may be good to do so as a regular preventive maintenance. May not need to, but minds does carboned up in no time. And I found out recently that you can clean your old ones and reuse them. I'd soak them in acids instead for couple of days turns the acid into a light grey colour from the carbon that had built up inside the sensors. The car idles much nicer after during cold start.