I got my head back from machine shop today
I had them clean and surface the head, head was milled 0.0015

I was reading up on supertech valve springs/retainers and it seems like OEM valve springs are good if I am not upgrading cams. I currently have no intention of upgrading OEM cams at this time. What would you guys do? Still upgrade to supertech or put back the OEM assembly?

Some pics of the cleaned and milled head
https://www.miataturbo.net/attachmen...ine=1406786725
https://www.miataturbo.net/attachmen...ine=1406786725


I have another question, what do you guys use to clean valves? I was able to clean my intake valves with wired dremmel wheel but exhaust valves are caked on with carbon and I can't even get them off with dremmel. Any recommendations?

intake valve before/after
https://www.miataturbo.net/attachmen...ine=1406786725

Media blasting with something that won't etch the metal?

Why didn't you have the machine shop cleanup the valves and do a valve job? Valves may not be seating properly or you could need valve guides replaced. If you are doing a rebuild/build like this, might as well have the valvetrain at 100%

I just like doing stuff on my own whenever I can. I'm out in the field til end of this month.

Well, originally, I was just going to clean it nice and lapping it before I put it back. I'm still indecisive on what I'm going to do with the head. Still researching and reading up on what I can do. If I go oversized valves, I'm going to drop it off for multi angle seats. If not, probably just match intake manifold ports on the head.

I find it odd you're debating forged pistons vs stock and now oversize valves vs stock. Forged pistons are almost a necessity for any serious build, oversized valves are almost totally unnecessary for any build. Are there gains to be had? Sure. But if you're budgeting that hard, look elsewhere.

Personally if I was going to the trouble of cleaning the head, I'd get new seals, guides, valve job and back cut the stock valves. I'm also a fan of uprated springs but that not necessary with stock cams (though I do like having some RPM headroom to avoid valve float say I ever miss a shift). A solid machine shop can do the work I recommended for peanuts and you know your valve train will be absolutely tip top.

You can blast with walnut shells and it won't deform the metal.

Thank you for putting me on the right track, I'll drop them off at the shop when I get back for valve job!

Pistons are just insurance for when something goes wrong. I am about 90 percent certain that my oil sprayer mishap would have shattered a cast piston instead of just destroying the skirt on my wiseco. Because the piston held together, I couldn't even tell what the problem was until I dropped the oil pan and peeked up the bore. If it had shattered, the rod would have no doubt punched the cylinder wall a bunch of times, killing both the block and the rod, which would have been way more expensive to fix in the long run. It's cheaper to replace pistons than to replace an engine.

Oversized valves are hugely expensive to do right and will give gains that can be easily achieved with your boost controller for free. Not worth it IMO. That being said, I think a good head refresh and stronger valve springs is a worthwhile investment if you have the head off for any reason.