Minor discrepancy in valve clearance reading

Question

I started my engine work on a V6 Toyota Tacoma 3 mohths ago and continuing now from where I left off. Back then I did a valve clearance measurement on all the 24 valves with all the timing chains on (main, left and right). I just took all the chains off and the reading I am getting are consistently 0.001" (one thousandth of an inch) less than what I was getting before.

Could it be that the removal of the timing chain caused a different reading (by slightly changing the position of the camshafts) or could it be because of different air temperature (August vs December)?

Answer 1

Ambient temps surely can cause the difference. .001" isn't much of a difference, either. Most likely, unless you were shooting on the tight side of lash, it's still going to be within tolerance.

but do you think the presence/absence of the timing chain also could? (from comments)

Not at all. The clearance is there set by the lash caps and the bearing journals. All the chain does is keeps things organized so pistons don't meet valves.