If you count the exhaust pipes on this experimental Cadillac engine, you could easily conclude that it’s a V10, but things are not always as they appear.
Several years ago at Mac’s Motor City Garage, we featured a fascinating but never-produced experimental Cadillac engine known internally at General Motors as the XV12. (You can review the story here.) Essentially a 7.5-liter, 12-cylinder version of Cadillac’s Northstar DOHC V8 with advanced upgrades including gasoline direct injection, the XV12 was first revealed at the 2002 Detroit Auto Show in the Cadillac Cien, a mid-engine coupe concept.
While the VX12 story attracted a sizable amount of interest, it drew some quizzical responses, too. First, some veteran Cadillac mechanics questioned the wisdom of adding four more cylinders to the already troublesome Northstar V8. (Eight cylinders were quite enough, thank you.) Also, a number of readers examined the story’s lead photo—the same image shown above—and, counting the exhaust pipes as they naturally would, they asked, “Hey, isn’t that engine a V10?” It’s a totally reasonable conclusion, as the photo seems to show five exhaust pipes on the bank facing the camera.
Fortunately, there’s a large, high-resolution version of the photo available for review. And a closeup detail, above, reveals the source of the freakish illusion. The fifth exhaust pipe in line is almost perfectly superimposed on the sixth pipe, effectively making the sixth pipe disappear from view. (Cylinders 9 and 11 if we follow the GM numbering convention.) It’s a one-in-a-million photo composition, fair to say. Photographers would have a hard time duplicating the illusion if they tried, but there it is, preserved for posterity. However, curious as the photo may be, it’s no more than a tiny footnote in Cadillac lore. The extended Northstar engine never went into production as a V10 or a V12.
Cadillac did in fact offer a V12 production engine at one time—from 1931 through 1937, to be exact. Designated the 370 series, the V12 (below) was closely based on the mighty Cadillac V16 architecture but with 368 cubic inches of displacment rather than 452 CID. Due no doubt to its significantly lower price, the V12 outsold the V16 by a fair margin, especially at first, and through much of the decade, Cadillac offered automobiles with your choice of V8, V12, or V16 power.
Wow, that is weird. Even after you see it the illusion remains intact.
I’m no mechanical engineer by any means, but as one who has never owned an engine with more than eight cylinders, those with 10 or more cylinders fascinate me.
In the case of Cadillac during the late 1920s and 1930s, the V12 and two V16s beg the question of “Why?” Was it for bragging rights, smoothness, or did the high cylinder count reduce the amount of shifting required in these pre-automatic transmission days? Or was it perhaps a combination of all of these factors?
power. back then the easiest and most cost effective way to increase HP was by adding cylinders.