14. Fuel: How long can it sit?

Gasoline does degrade over time, usually first by losing volatility. The chemical components added to gasoline during refining to promote vaporization and combustion can evaporate, especially in vintage cars with fuel systems that aren’t tightly sealed. That can result in a loss of power and increased emissions, but the good news is that topping off the tank is usually sufficient to bring the fuel back up to par.

The bigger issue is when fuel sits around long enough to begin to oxidize. That’s where the stereotypical gums and deposits that can clog carbs and filters come from. Let fuel sit long enough and you can expect to be going though the system from engine to tank. If there’s a question about whether the fuel is starting to oxidize, eyeballing it can actually tell you quite a bit; oxidized fuel is usually darker and has a stale smell. Compare the questionable fuel to a fresh sample; if the fresh one looks like “pale ale” and the aged more closely resembles an “amber,” that’s good evidence of oxidized fuel. If you really want to get precise, a gasoline hydrometer like the one offered by VP Racing Fuels is the way to go.

On top of that, most vintage cars have vented metal tanks. If they’re only partially filled, temperature swings can cause moisture to be drawn in and create condensation, which will not only water down the gas, but also promote rust in the tank.

Unfortunately there’s no single answer for how long gas can sit around since it all depends on the type and quality of the fuel, the type of fuel system, and its storage environment. Some can’t be counted on for more than a few months, while Rockett Racing says theirs is good for a solid two years due to lower levels of olefins and higher levels of additives to resist gum formation. Overall, a good rule of thumb is to add fuel stabilizer for any storage longer than several months. That can buy you roughly 12 to 15 months. Anything longer than that and you’re better off draining the system.

15. How do I know the internal condition of an engine without pulling it apart?

There are lots of tips and tricks for checking out used engines or junkyard finds, from those obvious ones like inspecting the ports and popping the valve covers off, to the more in-depth like inspecting a main bearing or sliding a borescope into the cylinders. But what if it’s in a running car you’re considering buying and you don’t have time or luxury of digging in?

If you really want to know what’s going on inside an engine and how it has been maintained, it’s the oil that can actually tell you just about everything you’d want to know. The oil can reveal the state of wear in the engine, fuel or contamination, whether the filtration is effective, and even whether or not the oil is still working or needs to be changed. That’s what oil analysis can do, and it’s cheap and easy. AMSOIL, Wix, and Blackstone Labs all have inexpensive test kits available that allow you to take a small sample of engine oil and mail it in for full analysis by their technicians. How useful can it be? Check out the sample reports on Oil Analyzers Inc. (the lab that handles AMSOIL’s testing) at www.oaitesting.com/ and also from Blackstone Labs at www.blackstone-labs.com.

16. What’s the cheapest and easiest way to go faster?

There are tons of quick bolt-ons that can yield significant bumps in horsepower and torque which will in turn make a car quicker, but from an all-around standpoint the king of them is still dieting. Take that as you like, but every pound that either you or the car drops is not only less weight to be propelled forward, but also less weight to stop or carry through a corner. In essence, you can make your car do everything more quickly by reducing curb weight and thereby reducing the forces working against you, even if horsepower stays the same.

The whole idea is to improve the power-to-weight ratio of the car and everything you can safely remove counts: carpet, sound deadening, passenger seat, A/C, stereo, and the like. Beyond that, swapping for lighter wheels and fiberglass, aluminum, or carbon-fiber body parts can all yield significant results.

The formulas for figuring out the gains through a corner or braking are complicated, but if you want to quickly check how much your weight loss is improving the car’s power-to-weight ratio, all you need is the weight of the car minus driver and cargo, and the horsepower of the engine: PW = Vehicle weight ÷ Horsepower. For example, for a C6 Corvette Z06: 3,133 pounds ÷ 505 hp = 6.2 lb-hp. Accuracy counts, and ideally you want to know flywheel horsepower, but even the chassis dyno results will give you something to compare as you lose pounds.