Greg W

I did my first valve adjustment on my '05 S2k AP2 w/56k miles. The intakes were spot on at 0.008", but the exhausts were only about 0.006" compared to specs of 0.010-0.011".

About 3 weeks ago at Thunderhill (entering turn 14), I did an inadvertent 5-2 downshift but caught it before the clutch fully engaged (CDV helped things as well). Could that have done something to the adjustment? I inspected the retainers and they all appear to be fine.

Have others had such a deviation from spec on their first adjustment?

As a curiosity, how would the performance be impacted by valves open 0.004" too much. I figure slightly hotter exhaust valves (more time in the hot gas stream, less time shedding heat to the head) and more power/poorer economy, but am just guessing. Thoughts?

Slows2k

.004 could all be in the tension you feel on the gauge. Don't loose any sleep over it.

starchland

ya i wouldnt worry about it. its common for the clearances to get tighter over time as the engine heat cycles...where as many would think the tolerances would get greater

SgtB

I agree with slow. Set a micrometer down to 0.01 and then think about how little 4/10 of that would be. I can slew a mic by almost 0.01 with poor tension adjustment.

chuhsi

my first valve adjustment was slightly too loose. I think it was the intake side. my power and fuel economy noticeably sucked until the valves were tightened to spec.