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Tuesday, May 17, 2011

GM: 90 MILLION V8S MOTOR MOUTH: ONE

By David Booth, National Post - This will hardly come as a surprise, but I'm a gear head. Like others so afflicted (that's how the rest of the human race describes our condition), I suffer a variety of symptoms. I spend all my money on things internally combusting. My spare room is a magazine-cluttered homage to Gordon Jennings, David E. Davis Jr. and Henry Manney III. Perhaps most annoyingly, all my metaphors, no matter what the subject at hand, inevitably end up automotive related. Pathetic as it may be, the automobile is my context for everything in life.

I have raced motorcycles, screamed along the autobahn at speeds I really don't want my mother to read about and, on more than one occasion, I have completely disassembled engines in my bedroom. In other words, there's grease under my fingernails. But I have never built a small-block Chevy.

Quite how I missed this rite of passage, I'm not quite sure. General Motors has built more than 90 million V8s of various displacements since 1955, and a large proportion of those have been built, hot rodded or otherwise tinkered with in the ensuing 56 years. It's not for lack of experience; I've rebuilt everything from Honda Civics to two-stroke motorcycles. But, somehow I've never spun a wrench on the most ubiquitous of North American engines.

Until now.

It turns out that General Motors has a brand new, very exclusive (as of my writing, only 15 people have participated) program that allows prospective customers of the company's Z06 and ZR1 Corvettes to go to suburban Detroit and build the 6.2-litre V8 that will power their very own supercar. It adds US$5,800 to the price of the car. Yes, paying extra to build your own engine is a little like going to McDonalds and paying a premium to fry your own burger, but I suspect there will be more enthusiasts clamouring for the opportunity if for no other reason than "I built that" will get you some serious props at the Sunday Show&Shine.

And you really do build your own engine. The Performance Build Centre in Wixom, Michigan, has an entire assembly line reserved for the amateurs among us. And, while one of the small factory's master technicians follows your every step so you don't put a camshaft where the crankshaft should be, you really do torque all the bolts and fit all the pistons yourself.

The reason GM is confident offering this service is that the entire process has been made virtually foolproof. The engine, as advertised, is completely hand-built, but the processes, tools and jigs the Performance Centre has created makes it very difficult for a mechanical faux pas.

One master artist -- or, as you can see from the picture, on ham-handed klutz supervised by a master artist -- builds the entire engine along a line of 11 sub-assembly "stations" in a system that is a combination of small artisan shop and large automated factory. Unlike a conventional production line, for instance, our engine has to be pushed manually -- thank God for this morning's Wheaties -- along to the next station.

On the other hand, every one of the torquing procedures is fail-safed by a computer monitoring system. Before you can screw the rocker arms to the head, for instance, you use a scan gun to calibrate the powered torque wrench. Not only does the computer inform the gun that 30 Newton-metres (yes, even GM has gone metric) of torque is the required amount of twist, it monitors that you're repeating the procedure exactly 16 times. Do it less -- or more -- and you will get a red light informing you, as it did me, of the aforementioned klutziness. You can't leave that substation until the issue is rectified and, at the very end of the entire build, the computer knows that a total of 367 torquing procedures were required for that particular engine and it checks to see if all have been tightened correctly. It even stores the information in case of future warranty issues.

Even more impressive, though, are the various jigs, guides and protectors the technicians have contrived to make the assembly process as idiot-proof as possible. Installing the camshaft -- a tedious procedure for the backyard mechanic -- is a doddle thanks to the guide GM has fashioned. An ingenious ring compressor and connecting rod protector, meanwhile, make it literally impossible to damage either the cylinder wall or the crankshaft bearing surfaces when even you-know-who is hammering the piston into the block. Even something as relatively inconsequential as the electronic "knock" sensor has its own jig so that, after it's bolted on, its outlet is perfectly aligned for the wiring loom it will eventually have to join.

Of course, the highlight comes after the assembly is complete. The last production line item is signing your name to the back of the intake manifold (some poor ZR1 owner is going to wonder who David Booth is). And, finally, there's joy/rapture/cold clammy relief when the engine starts for the first time. For gear heads of all stripes, it's nirvana.


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