1.8t vvt?

[Brett Dikeman]

At 5:15 PM -0500 2/11/03, Tom Leppke-Hennig wrote:
>Can anybody help settle a friendly dabate I have going with a friend? We
>are wondering if a 1.8t motor has variable valve timing. I say it
>doesn't, he says it does.
>
>Anybody out there have the straight dope?

They've been doing it on the V6 for years(more complexity as time
goes on, and variable intake geometry to boot at some point as well).
I believe the 1.8t only recently gained both technologies; not sure
when, but it might have come with the new redesigned A4.  Tech specs
I found quickly for the '99 model showed no variable nothin' on the
1.8t.

I saw the 5-valve V6 head on a display stand a while back; it's a
remarkably simple system- it has two sliders on the top+bottom of the
timing chain, and it moves the assembly to transfer the slack in the
chain, changing the driven cam's position relative to the other.  You
can push the piston up or down and actually see the other cam shift
slightly.

What's also interesting is how the 3rd valve in the 5-valve head is
at a different angle, which makes for an interesting cam lobe
setup...has a different profile to make it operate in concert with
the other two.

Brett
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