Engine building lesson for the day
 

A good friend and mentor, Walt Adriance used to have a saying.
It was both prophetic and financially motivated.

"Better than new, because it's tested".

The sign on the wall that explains that sentiment: "Sometimes new parts don't work"

From the manufacturers perspective they knew the difference. You'll often see something like, "Test using a known good part" in diagnostic trouble trees. GM even had a bulletin or two stating that fact.

Just because it's brand new in the box doesn't guarantee anything.

Never more true than in today’s world.

Of course you want to measure everything but issues get missed.
My intent in posting this simple concept is to suggest the it is very easy to ignore the "new" part when diagnosing a problem.

"Oh, it's can't be that, I already replaced it."

Like my 1 month old Uro antenna power mast that hasn't seen rain, click, da clickckckckckck.
new clutch release forks, new rod bolt centre diameter, valves with stem mating offset..., are the new valve springs really supposed to sit at an angle when placed on a flat surface? who knows, but in they went.. so on, can't remember what else, maybe nothing, but this is one engine.

I guess the more you work, the more you find.

I hear you Henry!
Nothing like a known tested part.
1. Like the 996 Turbo Fuel Pump directly from the dealer.
The connector was wired backwards.
2. two new Carrera tensioners that never pumped up. Replacing with other new ones pumped up immediately.
New Sebro intermediate shaft chain sprockets that were not large enough to fit on the shaft. Didn't matter how hot they got.
I could go on...

VR failed. Bought new one, failed within a couple of months. Next one worked fine when we sold the car several years later.