I copped to this in another post, but didn't mention the extent of the 'misadjusting' that I did. In short, *I think* I adjusted some or all of the valves when open. That is to say, when a valve was fully closed, I adjusted the opposite valve ala Krusty's method. No need to comment on how stupid this was, I get it and know how to tell when a valve is open vs closed now.

After the error was made, the engine was ran for ~5 minutes, at low RPMs. It has hydro lifters. Not surprising, it was noisy and had low power.
Since then I've done a proper valvue adjustment and ran it for another ~5 minutes, and it's still noisy. Not as noisy, but noisy. But with hydro lifters I'm used to noise when the car isn't driven for awhile and then it quiets down but I was afraid to run it any longer.

I plan on rechecking the valve clearance one more time before starting it up again, which I will do only because I'm at the point where I'm accepting that a rebuild is likely in my future sooner than planned.


So:
What is the likelihood I did permenant damage to something by setting valve clearance with the valves open?
My mistake resulted in a way too loose setting for some/all of the valves, so much so that the vavles may have not opened at all or opened very little when I ran it.
Given the short time I ran the engine, isn't the extent of the damage likely just to be potentially prematurely worn pushrood and lifter surfaces? And maybe there's a chance that it's noisy only because the lifters still need to do a lot of pumping up?

All of the rockers are intact (save for any cracks I can't see). All of the lifters seem to have a bit of air in them as I can compress them with the pusrhod via the rockers a bit.

I doubt there is any damage with no load, low RPM. Did your cam mfg specify a 20 min break in run @ X RPM ? Don't feel bad. I used Raby's full valve kit w/ chromaloy push rods. I set the valves @ .006 & .008 and wondered why it chattered before I remembered they were "0" clearance.

This wasn't a new engine build. PO rebuilt it with hydro lifters.

I would think there would be a chance of damage if they were too tight (valve/piston contact), not too loose.

Your still probably OK. If used parts were reinstalled; did you re-install the lifters to their original position? I can't speak to new lifters/old cam mating possibilities.

Well there's your problem. You're trying to "adjust" valve lash with hydraulic lifters as if it were a stock solid lifter. You should be starting with zero lash with hydraulic lifters (i.e. no 0.006 or 0.008 gap like a stock motor). The hydraulic lifters do the adjusting for you, which is the point. You shouldn't need to adjust the lash with them installed. I have read that some manuals recommend another 1-2 turns in after you reach zero lash at TDC to preload the lifters... but I'll defer to what the Cap'n and other folks think.

Either way, I'd bet that's why it's making an awful racket.

.006, .008, 0r 0 lash, doesn't really matter since he says he adjusted the valves with them open. Thats the real issue. I believe he was adjusting to 0 lash if I remember correctly.

I understand what you're saying, but the original poster said he understood his mistake.

What I was suggesting was to set TDC, adjust 4 valves to zero lash (plus 1 1/2 turns in). Then rotate the engine and do the other 4 the same way. THIS time understand that there are only three valves on ONE BANK that are open at TDC... and one on the other side.

I adjusted them at 0 lash + 1.5 turns, but since the valves were open when I adjusted them the amount matters little- all that needs to be said is that they were adjusted WAY too loose.