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New kids work on the engine block

For an extra $5,800, buyers of a Corvette ZR1 or Z06 can hand-assemble their car's engine.

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WIXOM, MICH.— For a mere $5,800 extra, buyers of Chevrolet Corvette Z06 or ZR1 models can build their own engines at the General Motors Performance Build Center here in this central Michigan town.

It takes about six to eight hours. Do the math. But they get a plaque to put on the engine with their name on it. For a car freak, can it get much better than this?

To date, only four customers have ticked this box on their order form, the fourth of whom happened to be the first Canadian: Mike Yurko from Vegreville, Alta.

Yurko took over the 5,000-acre family farm when his dad retired, and judging from his automotive fleet, he does okay: a Hummer, a Cadillac Escalade, a pristine 1969 Chevrolet Camaro Z28, and a black Corvette ZR1.

He had already decided to buy another ZR1 when he found out that the “Corvette Engine Build Experience,” introduced to the U.S. last July, was extended to Canada this year.

Carl Pickelman is site manager for the Performance Build Center.

He said that what they do is “essentially, bolt things onto engine blocks. It is all done by hand, each engine assembled solo by one of our 16 technicians.”

I tell him that the only other two operations I’m familiar with that do this are Aston Martin and AMG, Mercedes-Benz’s performance subsidiary.

“We have benchmarked ourselves against AMG, and against Hendricks Motorsports [one of NASCAR’s most successful teams],” he said.

“We do the LS3 for the Grand Sport manual transmission, coupes only — the theory here is that this is the version of the ‘regular’ Corvette most likely to be used as a track car, and probably the one whose owners would most likely want and benefit from a hand-assembled engine.

“We also do the LS7 7.0 litre for the Z06, and the LS9 Supercharged 6.2 litre for the ZR1. Buyers of these latter two can opt for our Engine Build Experience.”

The package includes accommodation for two, and the build process where the owner gets to assemble his engine with the help of one of the 16 pros.

Being a pro is considered a plum assignment. “We don’t have anybody in here currently who has less than 35 years on the job,” said Pickelman.

Three “material handlers” gather up the parts for each build, arrange them into “kits,” and bring them in proper sequence to the build stations along the line.

The assembler places the block on a wheeled cart, and shoves it manually from station to station. No robots here. At each station, the assembler scans the engine’s work sheet which has a bar code identifying the engine.

He then scans a code on the work station for each procedure performed at this station. The scanner reads the exact torque each bolt must be tightened to, and the number of bolts needed.

When the process is finished, another scan confirms that everything’s okay. When the eyes of “Jake,” the skull-shaped icon, turn green on the screen, that’s the signal to carry on.

Different templates are placed on the engine during various stages. These may list (for example) the sequence in which the bolts should be tightened, in order to ensure the pieces mate — and stay —perfectly flat and/or square to each other.

Perhaps the most critical part of the assembly process is fitting the crankshaft and pistons to the block. Yes, there are tolerances that must be measured and met.

But bearing shells, for example, may vary ever so slightly, and you have to guard against “tolerance build-up” — if two parts are both slightly off in the same direction, when they match up the combined tolerance might be too great.

When the crank is test-fitted, it’s turned by hand by the pro assembler, until it feels just right before the main bearing caps are torqued down.

When it’s all bolted together, the engine is subject to two running tests.

In the “cold test,” the engine is spun to 1,500 r.p.m. by an electric motor and checked for balance.

Don Henley — not The Eagles’ Don Henley — was doing one such test before Yurko’s engine got checked.

“We have a tolerance of one-half inch-ounce,” he said, pointing to the screen.

“To correct imbalance, you can either take metal out or put metal in. We have pre-drilled holes in the front pulley and the flywheel. We can tap in one or more of these tiny cylindrical weights to correct the balance at the front or back of the engine.”

A second run, and it falls well within tolerance.

Once that’s done, the engine goes to another dynamometer cell for the “hot test.” Here it runs under its own power for the first time.

Normally, Yurko is a calm-looking guy. You have to know that his face lit up when his engine fired up for the first time.

From here, the engine will be shipped to Bowling Green in Kentucky where it will be fitted to Yurko’s ZR1, which will be built in about three weeks.

Corvette also offers a program for customers to watch their car being assembled.

“I’d love to do that,” he says. “But I think we have something to do at the farm…”

jim@jimkenzie.com

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