Four-Links – the Mystery Machine demystified, Switch Pitch explained, Blue Train Bentley, celebrating the Defender

If you ever watched the mystery-solving Great Dane Scooby Doo on Saturday morning television (or now, in syndication), chances are good you wondered the same thing as Jalopnik’s Jason Torchinsky: what kind of van is the Mystery Machine, anyway?

* Ever wonder why Buick and Oldsmobile marketed, and then abandoned, variable-vane torque converters? KingElvis over at GM Inside News gives a thorough look at the pros and cons of GM’s torque converter designs.

* The car known today as the “Blue Train Bentley” isn’t the same one (or even the same model) used by Woolf Barnato to race “Le Train Bleu.” Even the original Gurney Nutting coupe owned by Barnato has been lost to time, but its modern recreation is beautifully depicted here by Jonathan Moore at Speedhunters.

* Land Rover’s venerable Defender goes out of production in late 2015 or early 2016, and this year’s Goodwood Revival will honor the legendary off-roader with a daily parade. The mix of models participating is said to be an eclectic one, and stretches from pre-production examples through civilian and military variants. Erin Baker at Goodwood Road and Racing has the full story.

* Finally, have you ever wondered how the GM “No Draft I.C.V. Ventilation” system worked? The Old Motor takes us through it.