I did take measurements from a completely Cold Engine, first thing in the morning, before Starting or running, on possibly a 30 deg C or 86 deg F Day.

What bothers me most is not the small clearances, but the Volvo Dealership less than 5,000km ago, reported the Cold Before and After Clearances on the Job Card
and they are different from mine. I measured mine twice, to be fair. And, as noted my Car now smokes going downhill, when initially re-accelerating from a slower speed limit to a higher one, but never smoked before they did the job.

Cold Valve Clearances:
At 146,829km, 02 December 2004
Cheney-Dutton Volvo Adjustment Report:
#1 Exhaust Before .350mm & After .350mm
#1 Intake Before .400mm & After .400mm
#2 Exhaust Before .450mm & After .400mm
#2 Intake Before .450mm & After .400mm
#3 Exhaust Before .500mm & After .400mm
#3 Intake Before .450mm & After .400mm
#4 Exhaust Before .450mm & After .350mm
#4 Intake Before .450mm & After .400mm

Cold Valve Clearances:
At 151,794km, 24 April 2005
My Measurements: Difference:
#1 Exhaust .330mm (-.020mm)
#1 Intake .406mm to .432mm (+.019mm)
#2 Exhaust .406mm (+.006mm)
#2 Intake .356mm (-.044mm)
#3 Exhaust .406mm (+.006mm)
#3 Intake .381mm (-.019mm)
#4 Exhaust .381mm to .406mm (+.0435mm)
#4 Intake .381mm (-.019mm)

Shouldn't the Valve Clearances all be the same .400mm? Why are #1 and #4 Exhaust Valves different on the Volvo Dealership's Clearances? And, why would my measurements be so different, from theirs ranging from .330mm to .432mm?

To address your comments, which I do appreciate:

Yes Rhys, I used a Feeler Gauge with the narrow part of the Lobe at "12 O'clock High", and simply inserted progressively thicker blades until I found one that was snug, then read the value on the Blade, such as, .406mm

Rule 308, why do you prefer a warm engine, then the question is how warm? Take it for a screaming run, uphill on a hot day, rip the Valve Cover off and check it or warm to the touch? The Clearances will change, as the temperatures of the Aluminum change, which is why in a Reciprocating Engine or Turbine Engine it is cautioned never to apply full power until the engine is at operating temperature, and Oil Temps are in the Green.

Trev29, you know me . . . I am a frustrated engineer. I maintain my car to very high standards and factory original.

Thanks, again, for your input.

RLC