Ian Drysdale keeps popping up whenever we talk about interesting engines, the Drysdale V8, the Carberry V-Twin, Russell Sutton's radial and a whole lot more, but as often happens, while digging around for information on another engine, I came across the Drysdale Godzilla V-Twin which I hadn't seen before. Ian must have some gene that prevents him from building anything ordinary because once you remove the covers of this V-Twin, you know there's some wizardry involved.
The cylinders of the 50 degree V-Twin are perfectly inline on a single pin crankshaft, something Ian wanted to achieve, but without the common knife and fork connecting rods that limit high rpm performance. He knew the big aircraft radials used a master and link configuration, so, being a true motorhead, he bought a Pratt and Whitney 4360 and shipped it to Australia. Gotta love that. Connecting rods in hand, he knew what he needed to do and designed a master and link rod arrangement for the V-Twin. Working with designer Tony Foale, they came up with a design to get the front and rear strokes and timing just right. Hurdle number one had been cleared.
Knowing any classic V-Twin should have pushrod valve actuation, he again went the unconventional route with an old design dating back to the 1930s and used in Mercedes GP cars and some old farm machinery, too, a longitudinal camshaft. A single cam with 25 degree conical lobes and driven by one pair of gears actuates the roller bearing hydraulic lifters that run in direct line with the cylinders, an interesting way to achieve parallel pushrods and quite a contrast to the three cam arrangement of the new Indian V-Twin. The result is far less gear noise and easier assembly and it just looks cool, too, a big plus for anyone who appreciates these things.
As any modern engine should, it has 4 valves per cylinder and a pair of gear driven balance shafts to create a very smooth running engine. Of course, Ian wasn't done yet. While the engine can be set up with normal aspiration and fuel injection, it was designed from the start to incorporate a supercharger in such a manner that it's almost unnoticeable. In the photo at the top, the little mechanism behind the rear cylinder that looks like a belt driven twin rotor supercharger, is exactly that! When all of the covers are on, you don't see it sitting out there like that, so think of the fun you could have. Good stuff.
The engine will be available in 3 displacements, 1398, 1602 and 1836cc. Though nothing is certain yet, Ian indicates he's talked with several parties about possible production, now wouldn't that be interesting?
When you look at all of the innovative features here, you have to think there's a bit of head slapping going on in some other design departments, with a lot of "Why didn't we think of that?" mumbling among the folks. Of course the simple answer is, "You're not Ian Drysdale." Geez, I like the way he thinks! I wonder where this will show up first.