Auto Performance FAQ (Part 2)

Here is part 2 of our series on reader submitted questions. If you missed it, part 1 is here.

WHAT DOES “AC” AND “DC” MEAN?

“AC” stands for alternating current and “DC” stands for direct current. Direct current is what’s in motor vehicles (12 volt DC). Alternating current is what powers homes, commerce and industry (120 volt AC).

The story goes that way back in the late 1800s Thomas Edison thought that DC ought to be the standard for home and commerce. The problem was that DC did not have the grunt to travel miles and miles from the power source to the end user.

Another guy named Tesla came along and invented the radio and other stuff and came up with 120-volt alternating current. The story goes that he licensed what he had invented to Westinghouse. AC alternates not in widths or spaces but by moving in a wave, alternating in polarity in a continuous cycle at the rate of 60 cycles per second. Arc-welding machines are both AC and DC.

AC machines generally use less electricity and are good for joining ferrous metals. DC machines power most professional arc-welders because it produces a smoother weld while offering a wider selection of welding rods. DC machines get the nod for welding stainless steel. Some arc-welders are both AC/DC thanks to an internal, built-in electrical rectifier.

WHAT’S FUSION AND NON-FUSION WELDING?

Both are technical terms for welding differences. Originally, welding comprised of joining metals through heat (that’s fusion). The metals were heated to the melting point – whereas they merged together. Non-fusion welding covers soldering and brazing – where a third metal is melted on two items – joining them together.

Solder is said to melt at between 250 – 750 degrees Fahrenheit (F). Aluminum melts at about 1,200 degrees F; cast iron melts at around 2,200 degrees F; stainless steel at around 2,500 degrees F; low carbon steel at around 2,700 degrees F and pure iron at about 2,800 degrees F.

WHAT’S THE OLDEST TYPE OF WELDING?

Experts agree it is oxygen-acetylene gas welding. It is also quite versatile, especially for use at home in your shop. There are two metal tanks – one for pressurized oxygen and the other for pressurized acetylene gas. Each has a set of gauges and regulators to measure the pressure and regulate the output as well as two hoses that connect to a torch.

Various welding tip configurations for the torch end are available. Tinted welding goggles or welding helmet is highly recommended so your retinas aren’t damaged due to the brightness of the flame. Besides welding, this system can do cutting as well; and that’s where its versatility is shown. Many feel this system is also the least expensive. Often, the hoses, torch and gauges are purchased and the pair of cylinders are leased.

WHAT’S ARC-WELDING?

Arc-welding according to many sources, including Haynes, is actually Shielded Metal Arc-Welding. The “arc” is the glow set off by the actual weld. The components include a power source, a “ground” lead cable that you place on the metal item to be welded, and an electrode lead, which runs from the power source to the holder.

An actual electrode lead is held within the holder. It is usually covered with a coating. In use, to strike an arc, the person touches the electrode/rod against the metal. This completes the circuit, and due to a lot of amperage being used, a very bright light with great concentrated heat is shown.

The electrode/rod melts and becomes the weld. The cover turns into a gas and is said to protect the weld from impurities. The end result is a covering of “slag” which must be chipped off with a hammer.

WHAT’S “MIG” WELDING?

MIG-welding has become a very popular home welding system. It stands for Metal Inert Gas. The setup usually includes an electrical power supply (welding machine), a large insulated cable with a torch on the end, a ground cable with clamp and a bottle of compressed shielding gas. Inside the welding machine is a roll of thin wire on a motorized wheel.

The welding is done similar to arc-welding but the wire is continuously fed through the insulated cable and out the torch/gun. When you pull the trigger of the torch/gun, the amperage melts the wire while being surrounded by the shielding gas. (It preserves the weld like flux does.)

The advantage of the MIG-welding system includes a much cleaner weld than either gas or arc. It is also quite versatile and does a good job welding thin metals. There is also no electrode/rod to keep replacing. Control is said to be easy. All you do is set the amperage via a dial on the machine and the wire speed.

WHAT’S “TIG” WELDING?

TIG stands for Tungsten Inert Gas, but it is commonly called “Heli-Arc” welding. It is said to be the Rolls Royce of the welding processes. Way back when, helium was used as the shielding gas. Today, argon is the most commonly used gas. Both gases have the capacity to exclude foreign matter during welding – plus they are unable to mix with any other gases or chemicals that could combine to be detrimental to the weld.

It differs from MIG in that it has a foot-operated amperage-control, a bottle of argon gas and lastly, the Tungsten electrode/rod is not consumed. Filler rod is hand-fed into the weld as needed. It also concentrates heat in a small area and is used with more of the exotic metals such as chrome moly, stainless steel and titanium.

A higher operator skill is needed to make those beautiful welds. All it takes is practice. It is the weld of choice for critical applications such as race cars and aircraft. There are no flying sparks and very little smoke.

HOW MUCH TIME DOES IT TAKE TO CHANGE AN INTAKE MANIFOLD?

Well, it depends. If you have experience and you’ve already changed the intake on the engine in question, we estimate you could do the job in one hour. If you are inexperienced or this is the first time you’ve touched the engine, it could take you four to six hours.

Why? Sometimes a valve cover must be removed for extra manifold clearance. Original intake manifold bolts and fittings could easily take one hour or more to clean with solvent and a wire brush.

WHAT’S THE HARDEST THING TO DO WHEN SWAPPING MANIFOLDS?

Mentally, if you are inexperienced, it’ll be removing and reinstalling the distributor. It has to phase-in with the oil pump intermediate shaft. We’ve seen worn cam-to-distributor gears that allowed the distributor to be installed one tooth off, causing it to idle and perform poorly.

Upon removing the distributor, we suggest you take a peek down that hole and see to which angle the slotted oil pump intermediate shaft is angled. If it moves to a different position before distributor reinstallation, the distributor will not drop in its final 1/2-inch until it is “phased” to the oil pump intermediate shaft notch. But then the rotor won’t be pointing at the distributor cap’s cylinder #1 terminal.

FIX: Get a long screwdriver and turn the shaft back where it was.

MY MANIFOLD’S BOLT HOLES DON’T LINE UP WITH THE HEADS.

If you’ve purchased a rebuilt engine or a used car, there’s a slight possibility that the heads were rebuilt and “milled” because they were warped. Heads can be milled as much as 0.030 to 0.100-inch – causing them to be lower in relation to their prior bolt hole lineup. This may only happen to one in a hundred of you but everyone needs to be aware of this.

When at the 0.100-inch level, there’s a good chance you may have a machine shop mill the front and rear aluminum intake manifold ledge so it will sit down lower and line up with the head bolt holes. You may still have to elongate the aluminum intake manifold bolt holes with a rat-tail file. No biggie. Welcome to the real world of do-it-yourself auto maintenance.

WHAT’S THE SECOND HARDEST THING?

It’s cleaning the old gasket material off the heads. Jobs like this teach something you never learned in school and that’s patience. Before you touch a gasket scraper or single-edged razor blade to the heads, you MUST lay a plastic trash bag, paper towels or shop rags in the lifter valley to protect the area from falling dirt, carbon, coolant and other foreign matter.

NEXT, we highly suggest you stuff a wadded up paper towel into each intake port so no dirt or carbon can fall down into the port and land on the top of the intake valve. Ditto for engine coolant.

FINALLY, we recommend you have a shop vacuum cleaner nearby to use as a scraper removal aid. As you scrape off the gasket, it goes immediately into the shop vacuum hose. A bonified gasket scraper does a nice job although for little pieces of gasket and RTV, a single-edged razor blade does a perfect job.

After you’ve finished, run your fingers over the heads to see if you missed anything. If any junk fell into any of the intake ports, use the shop vacuum to remove it. Cleaning both heads can take a studious 15 to 30 minutes. Do it right the first time because you do not want to do it again.

WILL AN 8,000 RPM OPEN PLENUM, DOG LEG MANIFOLD MAKE MY STOCK 5,000 RPM V8 ENGINE RUN BETTER?

Some have tried and all have failed. Factory V8 intake manifolds have been, by design, 180-degree/dual-plane, for torque enhancement. Race manifolds, by design, are 360-degree/single plane, for horsepower enhancement. Race engines do not need 1,000 rpm to 3,500 rpm “torque, horsepower and driveability”. Street engines do.

Yes, some can rev in excess of 6,000 rpm but all street engines spend most of their time working part-throttle at lesser rpm. Having that Weiand Stealth dual-plane intake manifold help attain 42 more horsepower on a low compression, smog motor 454 is pretty cool. And look at all the fuel the engine would not have consumed over the years, too. Way to go Sam, Dave and Weiand.

WHAT’S BETTER, MECHANICAL/SURGE BRAKES OR ELECTRICAL?

We’ll begin by stating that “any” brakes are better than “no” brakes. For decades, many trailers had no brakes. Then along came mechanical brakes – braking action activated by wheel cylinders pressurized by brake fluid did a good job. Upon actual tow vehicle braking the mechanical brakes were activated by a “surge” assembly located at the front of the trailer that was activated by the dropping of the trailer nose due to braking.

By comparison, electrically-activated brakes come alive the instant the tow vehicle’s brake pedal is depressed. No chassis or trailer movement is necessary. Either is better than none but electrical is better than mechanical.

WHY ARE ELECTRIC BRAKES ADJUSTABLE AT THE BRAKE CONTROLLER?

The shocking thing about electricity (no pun intended) is that it is adjustable. The bright or dim glow of a light bulb is adjustable via a regulator or rheostat. We can tell you from experience that electric brakes offer such a vast high degree of grabbing that while going slow in a city street, alley or parking lot, that they can bring you to a lurch by locking up.

To eliminate the locking up, the brake controller regulates the voltage / amperage to the trailer brakes for smooth trailer brake application. The adjustment on the controller readout should say lower setting for lighter weight and slow speeds, and a higher setting for more brake application at highway speeds or heavy loads.

The numbers can vary depending upon a lot of factors, ie: brake condition and adjustment, condition of wiring, and weight of trailer vs number of brakes used. Now, when you’re towing at legal road speed and you must stop quickly, you do so effortlessly.

WHEN I LAUNCH MY BOAT, MY “BRAKE” FUSE KEEPS BLOWING. WHY?

Simple, somehow your wiring at the brakes is not “water proof”. Be happy you blew a fuse. Otherwise, the next one standing in the water who touches that wire is going to have a very shocking 12 volt experience. Consult with the pros at your marina as well as with the trailer manufacturer for recommended repairs.

This happens a lot due to an aging of the wire’s insulation, road vibration that may crack the insulation or a torn wire inside the brake assembly.

HOW COME MOST TRAILERS DON’T HAVE SHOCK ABSORBERS?

Trailers, from open car haulers to single and dual axle RV trailers have never had shock absorbers primarily because of their multi-leaf spring’s “arc”. The springs are fairly flat and heavy and do not normally move up and down a lot. But when they do, if there’s no shock absorber, there’s no stopping them until the tow vehicle slows dramatically.

Once a trailer starts whipping back and forth, it’s loading one leaf spring with energy then the other. A shock absorber can dampen this energy and keep the trailer under control. There are aftermarket bolt-on shock absorber kits a few years for a lot of different trailers. See your dealer for pricing and availability.

HOW DO I MOUNT AN AFTERMARKET MECHANICAL FAN ?

The radiator is re-cored and flows as new but a big seven-blade mechanical fan instead of the factory five-blade multi-viscous (clutch-type) fan assembly was added. Gee, the engine keeps running hotter and hotter until it reaches 240 degrees. And it won’t cool down.

How so? The actual fan position in relation to the fan shroud is not aligned. A two-inch fan spacer placed the fan just inside the fan shroud. The factory fan’s front edge was parallel with the back edge of the fan shroud. This one-inch difference in fan positioning let only the center of the radiator draw in air. Air coming through the outer fins was cut off.

The shroud could not do what it was designed to do. A change to a one-inch spacer and shorter bolts pulled the new fan back parallel to the fan shroud’s edge and the engine cooled properly forever after.

HOW MUCH MORE HORSEPOWER CAN A STOCK RADIATOR HANDLE?

The extra heat generated from more horsepower being produced is large, especially during long distance/endurance racing or when towing across country. How much more can a radiator handle depends on the fin cross section of the radiator. Adding 30-percent more horsepower to a two-core radiator (300 horsepower + 30-percent = 390 horsepower) is about max.

Make a few runs at the drags and see how the radiator likes it. It doesn’t. It can’t cool down. A three-core radiator is a must in this situation. This reminds me of a story where a faulty radiator overflow tank got the best of me. But anyway, most V8 engines that we are aware of have a mechanical water pump capable of pushing anywhere from 60 to 75 gallons per minute through the block and heads.

If you were to increase horsepower 60-percent or more you better be prepared to also increase the coolant flow capacity up to the 100 gpm range.

IS IT POSSIBLE TO OVERCOOL AN ENGINE?

Many of the Big Three engine specialists used to say that an engine produces the same power at 160 degrees F. as it does at 190. Famed engine wizard and old friend, Smokey Yunick is quoted as stating that V8 race engine horsepower is 2-3-percent more at 200 degrees F. water temperature than at 180 degrees F. He also feels the cooling system should be pressurized at 25 psi.

Be sure your radiator can handle this much pressure. Most street radiators can’t. He also feels that more horsepower can be made all the way up to 220 degrees F. but this temp leaves little temperature safety, so 210 degrees is max. Now mind you, Smokey is talking race engine stuff. We’re passing it on for your education. Street engines are different in that they have tighter piston-to-cylinder wall clearances, etc.

There are other tuning factors to consider as well such as total timing and carburetor jetting. Changing each in search for more power at full-throttle can possibly mean a temp change of as much as 10-15 degrees. Trust us, the temperature measuring point is where the coolant is returned to the radiator.

SHOULD I USE FACTORY TORQUE-TO-YIELD BOLTS OR WHAT?

Should I buy another set of factory torque-to-yield head bolts or should I go with aftermarket studs or head bolts? Believe it or not, it depends! Do you plan to remove the heads again during the course of your ownership? If so, you’d be better off with a set of aftermarket head bolts. Factory torque-to-yield bolts aren’t that cheap anyway and they can only be used once.

Head studs serve two purposes: For the racer who removes the heads a lot, studs are the way to go because you’re not wearing out the block threads. We’ve seen many a factory block start pulling threads after as few as two or three head bolt torque-downs. Studs are also said to give a more exact torque reading and this is very important in all engines – especially high performance, competition ones.

I SURE LIKE NITROUS OXIDE. IN CONSIDERING IT TO BUY, WHAT SHOULD BE MY BIGGEST CONCERN?

Both Jon and I agree that your number one concern should have nothing to do with nitrous oxide and EVERYTHING to do with your engine. Concern yourself totally with its internal condition – especially the piston rings and valve guides.

Nitrous oxide likes a tight engine. It doesn’t like to mix with oil, so if you have an engine with worn piston rings and/or valve guides don’t bolt on nitrous oxide.

DOES NITROUS OXIDE MAKE MY ENGINE WEAR QUICKER?

In the sense of normal frictional wear, no. Factory or aftermarket piston rings in a performance engine normally wear well for 30,000 – 50,000 miles – depending on the gearing, the driver’s right foot and high rpm use. A good nitrous oxide system should not, all things considered, hasten ring wear.

Too much ignition timing tends to lean the mixture slightly causing the moly to flake off the top ring. The ring then loses its sealing ability and oil consumption increases. Bottom line: Pay strict attention to the installation and operation instructions and do not vary from them.

WILL MY TRANSMISSION, BRAKES AND SUSPENSION HOLD UP WITH NITROUS OXIDE?

Most nitrous oxide street systems increase horsepower by 100 and torque output by 50-75 foot pounds of torque. The next bigger kit might be 150 horsepower and 75-100 foot pounds of torque. Most American V8s can handle this although we do recommend the transmission be checked out and a shift reprogramming kit installed to increase the line pressure for quicker shifts.

Huh? Generally speaking, every time an automatic transmission shifts, the temperature at the clutch pack facings increases 25 degrees. A quicker shift will decrease friction and the temperature as well.

Some rear ends such as the Monza/Vega with a 7.50-inch diameter ring gear will eventually break either the spider gears, Ring gear or an axle, so a word from the wise should be sufficient.

Nitrous oxide on a V6 Chevy S-10 or Ford Ranger may prove to be disastrous due to the miniscule driveline(transmission and rear end). It pays to ask, so quiz the nitrous oxide manufacturer for its recommendation.

WILL MY TIRES AND SUSPENSION BE ABLE TO CONTROL THE POWER?

First of all, nitrous oxide was created to enhance straight-line acceleration. It was NEVER invented for canyon racers or anyone driving around a curve or corner, banked or otherwise. Driving Crank & Chrome’s 300 horsepower Z28 Camaro is one thing but 450 horsepower is strictly another.

As stout a suspension and high-speed tires that this Z28 Camaro has, trying to make it control 450 horsepower through a turn would be, in three words: unwise and unsafe. Generally speaking, tires, suspension and brakes all must be in optimum or better-than-optimum condition.

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