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1971 Corvette Stingray - All Systems Go!

Our C3 Project Gets Ready To Hit The Road

Dave Young Sep 1, 2009

We've Got Project Cars!
Whether considering automobiles, homes, or antique furniture, purchasing someone else's used property generally comes with the aggravation of making repairs. As even a well-maintained house will eventually need a new roof, and a well-preserved piece of antique furniture will inevitably need to be refinished, a used automobile--especially a performance model--can likewise present a variety of issues that need to be addressed before the car is driven. Such is the case with our latest project, a '71 Stingray we recently picked up from eBay. Although we feel like we got a lot for our money with this purchase, there were several areas that needed attention before the car could be deemed roadworthy. This month we'll completely inspect our project vehicle, and perform some necessary routine (and not-so-routine) maintenance before hitting the road. Though we're working on a C3, remember that our techniques can be applied to any used vehicle prior to trusting it on the streets.

Knowing that even a fairly new Corvette may have been poorly maintained or improperly modified by its previous owner(s), we decided to give our Stingray a thorough mechanical evaluation to determine its roadworthiness. Of course, you may not care to perform this work yourself, but if you don't have the skills or desire to mechanically evaluate a used car you've recently purchased, we suggest taking it to a mechanic who can inspect it for you. As you'll see, we found a couple of safety-related items with our Stingray that could have led to catastrophic results had they gone unnoticed.

It's always a good idea to inspect a vehicle before purchasing it, but since we made our transaction over the Internet, we could only rely on the description and pictures the seller posted on the website. Luckily, the vehicle we purchased was basically as described in the advertisement, with the major mechanical components in pretty good shape. When inspecting a vehicle like ours, we generally begin with the obvious, like looking under the car for puddles of leaking fluids. Next, safety-related items such as the brakes, suspension, fuel and electrical systems, and seatbelts should be inspected. Of course, the airbags of newer cars should be checked as well, as they are sometimes not replaced properly after being deployed. Since our Stingray is a '71 model, we didn't have to worry about that.

What we did worry about was the odor of fuel when we started the car. Since there are basically two systems in a car that can catch fire, and the fuel system is one of them, we had to make sure ours was working properly and not leaking. Starting at the rear of the vehicle, we discovered that the fuel tank and main supply line had been replaced with new parts, but as we worked our way forward we found out where the scent of petrol was originating. The fuel line connecting the main supply line to the carburetor, through the filter, was a mismatch of steel tubing and rubber hose of various sizes. Making matters worse, several fuel-line clamps were incorrectly sized; this was the main cause of the leaks. After making the necessary fuel-system repairs, we moved on to the second system that could cause a fire, the car's electrical system.

Like all domestic cars of its era, the '71 Corvette is equipped with a 12-volt, negative-ground electrical system, with an alternator providing power while the car is running. While this type of system is basically safe, the electrical hardware in our Stingray was nearly 40 years old, so we decided to carefully inspect it for issues. Under the hood, we checked the wiring harnesses for bare wires or chafed insulation. We then checked the car's lights, all of which worked after replacing a couple of bulbs. Unfortunately, a previous owner had installed a pair of electric fans, and the wiring was a mess. To rectify this, we removed the fans and wiring and replaced them with the stock engine-driven fan and factory fan shroud. The worst thing we found, however, was evidence of a fire under the hood, in the area of the HVAC box. Though the damage was minor and looked to have been repaired, we checked the wiring and discovered what was likely a contributing factor in the fire. The fuse for the heat and air-conditioning had been wrapped in aluminum foil in an apparent attempt to make a shorted fan operable. While we've seen this done more than once, we still can't believe people are willing to risk their cars by bypassing the fuse, which is a safety device. We quickly removed the foil-wrapped fuse and replaced it with a fuse of the appropriate amperage rating, then moved on to find the remainder of the car's electrical system in roadworthy condition.

Continuing on, we placed the car on a lift to inspect the undercarriage and brakes, and to change all the fluids. We always like to change the oil, transmission fluid, and differential oil in any recently purchased vehicle, as the previous owner may have neglected to follow fluid-change intervals while the car was up for sale. While draining the fluid from the engine and transmission, we carefully checked the brakes for any signs of wear or leaks, checked the universal joints (all six of them), and looked over the suspension bushings and steering to evaluate their condition and verify the proper installation of the cotter pins. Fortunately, the brakes, suspension, universal joints, and steering on our car had been serviced recently, and were in great shape just like the previous owner claimed. With those checks completed, we finished changing the oil and transmission fluid and addressed the rear differential.

Because every C3 came equipped with an independent suspension, the car's differential presents a specific problem when it comes to routine service. Since the differential's center section is an integral part of the car's chassis, the rearend cover can't be removed without first removing a significant number of rear-suspension components. Not wanting to disassemble the suspension just to change the gear oil, we had to choose between siphoning the fluid out with a suction device (which won't completely remove the old fluid), and drilling a hole in the housing to modify it for a drain plug. Since we'll likely be driving this vehicle aggressively and will therefore need to service the fluids fairly often, we opted to install a drain plug by drilling and threading the bottom of the center section housing with a 1/8-inch pipe tap. There are kits available that allow you to perform this modification, or you can get all the necessary items at the local hardware store. Since we had all the tools and the proper plug in our shop, we simply performed the work there.

Otherwise, our '71 Stingray seemed fit for the road, despite being "cosmetically challenged," as Editor Heath wrote in his recent column. The engine recently had been rebuilt and runs fairly cool with good oil pressure. The clutch and pressure plate had also been replaced by the previous owner, so with our inspection and maintenance complete, we deemed the car ready for a road trip. To build confidence we began driving short distances, and have since gradually increased the length of our jaunts. So far, we've made the 60-or-so-mile round trip to the office and back without incident and have been putting the car through its paces regularly on the street. Next month, we'll tackle the Vette's subpar aesthetics, and possibly head to the dragstrip for some baseline testing.

We still haven't named this project, so be sure to send us your suggestions and let us know what modifications you'd like to see performed. As always, we can be reached at



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