One of the most important additions you can make to your Buick is a quality set of aftermarket gauges. If your car came factory equipped with idiot lights, this is even more important. By the time you see an idiot light, the problem is critical, and engine damage is imminent. Gauges allow you to see a problem coming. If you are familiar with your carís normal readings, you can spot an abnormal reading, stop the car and investigate, before a problem causes damage or leaves you stranded on the side of the road. The stock gauges are better than lights, but they have no markings on them, so you really donít know where your engine is running. For example, the stock temperature gauge on a Skylark/GS will be running at 200-210* when the indicator is halfway. Thatís quite a bit warmer than I like my engine to run.
The most important gauges to have are oil pressure and coolant temperature. I also run a voltmeter. A broken fan belt would first show as a low voltage reading and a generator light. The engine would then shortly overheat from a non-functional water pump and fan. Gauges come in two popular sizes. 2 1/16Ē, and 2 5/8Ē. If you have the room, I recommend the larger gauges. They are easier to see and read. Get the best gauges you can afford. In my opinion, you canít beat Autometer gauges. They have a budget line of gauges under the Autogage line. Get the better gauges if you can. I like to mount my gauges under the dashboard. If you want to keep the interior of the car original looking, use the smaller size gauges, and mount them in the glove box. Mounting bezels can be ordered from the same place you get the gauges. Jegs, and Sumitt Racing have a very complete selection. You can also get angle rings that let you aim the gauges toward the driving position. There are also mounting cups that enclose the back of the gauge and allow you to aim it. The mounting cups are more expensive, and you need to buy one for each gauge you are using. I use a bezel and angle rings.
The next decision you need to make is whether you want mechanical gauges or electrical gauges. There is no accuracy difference between the two. Up until recently, electrical gauges were of the 90* sweep design. Mechanical gauges have a 270* sweep. The 270* sweep means there are more lines on the gauge, and that means the gauges are easier to read accurately at a glance. For instance, the Autometer mechanical oil pressure gauge has a line every 5 psi, the electrical gauge has a line every 12.5 psi. If the needle is in between lines, it would be much easier to read the mechanical gauge at a glance, but both gauges would show the same reading. Recently, Autometer has introduced a line of full sweep electrical gauges, but they are close to twice as expensive as the full sweep mechanicals and short sweep electrical. Electrical and mechanical gauges each have their advantages and disadvantages. Electrical gauges can be easier to install. It is easier to run a wire than a tube. Mechanical gauges measure directly, and will work with no electrical power. The oil pressure gauge entails running a tube that carries the oil inside the car to the gauge mounting position. A nylon tube is commonly supplied for this purpose. The nylon can harden with heat and age, and can break spilling oil inside the car. A better choice is to use the copper tubing, or, even better, braided stainless steel hoses with fittings. Mechanical temperature gauges come in two ranges, 120-240*, and 140-280*. I like the 120-240* type. It places the normal readings of 180* closer to the center of the gauge sweep, besides, I donít need a reading of 280* on a gauge, Iím going to shut my engine down once I see 220*, and find out why it is running so hot. Mechanical temperature gauges come assembled with the sending unit. A sealed copper tube runs from the gauge to the sending bulb. The tube is filled with an ether type gas that transmits the readings. These gauges are harder to install because you must have a 7/8Ē hole in the firewall to pass the sending bulb through.
After you decide where to mount your gauges, and have mounted the gauges in the bezel or individual cups, the next task is to run the wiring, and or tubing. I have found that in the Skylark/GS, the easiest place to go through the firewall is where the climate control vacuum hoses are. There is a large rubber grommet over a inch in diameter. It is easy to poke a hole through this grommet, and run your wires or tubes. If you drill any holes in the firewall, remember to use a grommet to protect the connections from sharp edges. I have found that the easiest way to run lighting for the gauges is to connect all the lighting power leads together, and run one wire that taps into the ashtray light wire. This enables you to dim the gauge lighting along with all the other dash lights. Also run all the lighting grounds together, and run the single ground to a metal portion of the dashboard. I use one of the mounting screws for my bezel.
If you want to keep your stock gauges or lights operational, along with the aftermarket gauges, you can use a brass tee for oil pressure. With a temperature gauge, a tee is not practical because of size and clearance constraints. I use the threaded hole in the intake that housed the stock thermo-vacuum switch. That way, I can run both temperature gauges.