Design, Build, Test, Iterate

Z4 power top lock fix (also my first 3D print!)

Belated post from July 6.

Z4 power top lock gearbox innards

Z4 power top lock gearbox innards

The broken power top was the issue that led me to drain the battery and to watch as the car dumped half of its coolant onto the concrete. With some of the more critical fixes out of the way, I used this as an excuse to learn how to use the robotics club’s new 3D printer (a Solidoodle).

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Z4 headlight restoration

Belated post from June 3.

Sanded, clearcoated, and polished

Sanded, clearcoated, and polished

Careful wet sanding from 1000 down to 2500 grit, some polishing compound, and clearcoat (and more sanding/polishing) made my headlights as good as new.

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Z4 spark plug check

Belated post from May 30.

Spark plug looks fine. Bah.

Spark plug looks fine. Bah.

I was still debugging the RPM drop issue during ignition. Thought it might be bad spark plugs, though in hindsight that would have caused the engine to run rough all the time, not only during ignition. As far as I can tell from this guide, these spark plugs looked fine.

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Z4 valve cover gasket replacement

Belated post from May 23.

No sludge!

No sludge!

Replaced valve cover gasket to resolve a slow oil leak and mayonnaise under the oil cap. The more I work on this car, the simpler it seems. With the cylinder head so easily in view like this, even the infamous “blown head gasket” isn’t so menacing anymore.

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Z4 DISA valve fix

Belated post from May 21.

“Differenzierte Sauganlage” (differential air intake)

For a couple of months, I’d thought the gurgling noise emanating from somewhere under the dash was caused by air trapped in some fluid — coolant, maybe. It turned out to be a loose piece of plastic in the intake manifold.

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