Just asking:
How long did you break-in the new head?

Long shot: it is a F20 head.. right?

Interesting problem though.
I hope you solve it and post what it was.

 

Correct. F20 head, all genuine Honda parts. Head break in period around 500 miles. three consecutive oil changes with dino oil and filter in three consecutive days. Head has over 2500 miles on it now and problem still persists. strange because my lower nonvtec range is super abnormally strong, and it gets weak in vtec. weird.

 

Compression/leakdown test results?

 

compression and leak down check 4.0. on a side note, I am a former Honda Tech, all the usual checks have been performed, kinda why I'm on here, seeing if anyone has heard of this oddity.

 

changed plugs again today just for the hell of it. no effect.

 

Sounds like a few VTEC pins fell out while the rocker assy was on the bench. Once removed, the slightest incline will allow the VTEC pins to slide right out.

 

exactly what I was thinking, but verified they are all there, could they be stuck maybe? And true, they are a pain to keep in place when reinstalling it.

 

They are different as well. Did some fall out and get mixed up?

 

yes they did fall out, I am aware there are different sizes, the center ones are longer than the ones on the rocker arms themselves. All this talk makes me wanna take it apart and double check it again. It really feels like its not activating and choking for air at high rpm, but the audible sound of vtec makes me think at a minimum one cylinder is activating. refreshing to hear you are thinking the same thing.

 

If you dun't have VTEC, the motor won't run well above 6k rpm's. The motor needs the second set of cam lobes to run properly above 6k.

What you describe sound's like VTEC does not engage above 6k rpm's which is why the motor runs like caca.