I am curious if aluminum blocks are still assumed to lose power over an iron block?
I checked the lash this afternoon, block was at 65 degrees. Lash was loose on all, some as loose as .011 intake, many at .009. Cam card says . 019 intake lash, .020 exhaust lash. I set them at . 006 intake and .007 exhaust at 71 degrees block temp before the dyno session.
Since the valvetrain is all new except the lifters, i expected to see .002 extra due to breakin. But with some as wide as .011 i wonder if that could have cost me a couple of ponies. I did attempt to set the lash after a number of full pulls, but was not able to accurately check at tdc, 90, 180, 270 where i wanted to. Which brings up another test i can do now that i have the drive manderal off, exposing the damper bolt. I want to see where i should be checking lash, which i assume would be close to the zero lash point on the ramps. I charted actual lash change every five degrees on the base circle and saw the lash go from . 019 to . 025 in the middle of the base circle, then gradually back to . 019. The actual duration on the intakes is 350 degrees. At . 050 lobe lift it is 284 degrees. So the ramp is 33 degrees long on each side before reaching .000 to start valve lift. I am a bit paranoid over this, having had more than my share of broken valvetrain parts over the years.