What is core shift and why is it detrimental?

What is core shift and why is it detrimental?

How a clever concept remedied misalignment in competition engine blocks – By Archie Bosman: No other engine deficiency would have irritated racers, particularly professional drag racers of the last century, like core shift. A bitter source of anguish, they would describe it in a way not easily forgotten. “We used mostly Hemi blocks,” commented “Mongoose” McEwen. “Often we would test fifteen-to-twenty blocks before finding one with consistent cylinder wall thickness. Keith Black had a method of measuring them, which typically demonstrated core-shift variations from around 0.090in or 0.100in to 0.040in. Consequently, if we raced those engines, the severity of the internal pressures usually split the cylinder walls.” As you can guess, the impediment of core shift didn’t debilitate just the racing Hemi; Funny Car racer “Wild Wilfred” Boutilier’s reject ratio with big-block Chevrolets was similar. So there they were pencil and pad in hand, slavishly enumerating cylinder wall thicknesses, one engine block at a time. The term core shift relates to the deviation of a foundry core during the casting process. That is to say, the core moves from its original position, perhaps as a result of inaccuracies in the machining process or the setting of the mold, and leads to alignment problems when the mold is closed. Mold temperatures or pressure differentials on opposing mold walls also cause deflections of the cores. Whatever the cause, the result is evidenced by undesirable variations in wall thickness, which affects the final shape and, thus, the mechanical performance of the part. The Remedy: The problem has now been resolved by substituting multiple conventional foundry segmented cores with a one-piece major core....
Eaton Detroit Spring: Leaf and coil

Eaton Detroit Spring: Leaf and coil

By Martha Maglone: This summer marks the 80th anniversary of the advent of the Eaton Detroit Spring company. Founded during the Great Depression, the company is one of the most successful in the manufacture of leaf and coil springs and related attaching parts for the auto restoration and street rod markets. “The firm was first started by my grandparents, Frank and Grace” says current President, Mike Eaton. An aftermarket division of Detroit Steel Products, the Eatons originally purchased the company for $11,000. It was a perilous time; the country’s economy was stalled and prospects uncertain. Yet it thrived and a few years later, when the original lease expired, production was moved to the corner of Michigan and Trumbull—across from the former home of the Detroit Tigers baseball team. The firm still operates from this location today, manufacturing springs and components for the classic vehicles it watched debut and mature over the decades. Significantly, Eaton Detroit Spring possesses over 24,000 OEM spring blueprints for more than 166,000 vehicle applications, covering fitment for nearly every classic, muscle car or hot rod application that comes its way. “Our blueprints give us a substantial edge in leaf spring design and manufacture over our rivals,” claims Eaton. “If you provide us accurate information and install the springs correctly, the likelihood of a problem arising is remote.” Eaton’s passion is springs and, helpfully, they’ve combined it with access to an expert design staff. Dedicated to custom applications, they are willing to assist in all spring-related inquiries.  Mike Eaton again, “Others may sell springs, we make them. That’s our specialty—just as it’s been for the past 80...
Ignition for beginners

Ignition for beginners

Extracts from Drag Racer magazine, September issue: By Ben Mozart:    Early in 2017, a new capacitive discharge (CD) ignition system emerged. An innovative philosophy derived from new software—”a proprietary algorithm” as it’s known in engineering jargon, it promises substantially more than previously available. Designed to operate with a single-coil distributed spark, which includes most carbureted drag racing applications, it’s reputed to be smaller in size than any CD device with similar features. Of greater significance, it is more energy-dense, maintaining multiple spark activity from idle to 7,000rpm as well as generating greater sparking power. There are two common types of ignition systems: capacitive and inductive. The coil is supplied power by one or the other. Inductive, which is still the most common and employed on most road-going passenger cars, charges the coil with 14.6 volts and discharges between 200-300 volts into the coil’s secondary windings. Inductive systems are any of those ignition systems that do not have a capacitor energizing the coil. Inductive systems have power applied to the coil for a period of time but their electro-magnetic principals are the limiting factors as to how quickly the coil charges and how much energy it discharges. Properly seen, the standard inductive ignition system is designed to start vehicles in all climatic conditions, including those operating in temperatures of 20 degrees F. below zero rather than supporting vehicles with high compression ratios or high horsepower or high rpm. Capacitive ignition systems on the other hand are developed for high performance and racing vehicles, which operate at high RPM and generate higher cylinder pressures. Higher cylinder pressures mean the spark...
How to avoid your next traffic ticket

How to avoid your next traffic ticket

By Martha Maglone – A recent article from Your Mechanic asks: Does the type of car you drive make a difference to the amount of tickets it might receive? The most ticketed luxury car is the Lexus ES 300 and the least ticketed compact car the Honda Civic. In 2016, Insurance.com released a study ranking car models with the highest number of speeding tickets and traffic violations. Data derived from over 323,000 offenses, revealed the Lexus ES 300 and the Nissan 350Z were the highest ticketed cars, with about one-third of drivers caught violating traffic laws particularly those involving speeding. But does the category of vehicle make a difference in the amount of tickets it received? When classified by luxury cars, mid-sized, compact, sports cars, pickup trucks, SUVs, and subcompact cars, it revealed some interesting findings, not least the types of drivers typically receiving the most, and least tickets. It’s important to note that traffic violations can differ from state to state, but some of the most common include running a red light, driving at night without headlights, illegal turns, illegal parking, or running a stop sign. Speeding laws also fluctuate based on the State and road conditions. This article gives data on ten categories of cars. Read...
Streamlined Era – Pics from the past

Streamlined Era – Pics from the past

Streamlining is a form of structure that lessens resistance and turbulence to air flow. Although its golden age is normally associated with the nineteen-thirties, the first streamlined car, the Rumpler Tropfenwagen emerged in 1921. Streamline-inspired forms were most prominent in aircraft designs, but they were also applied to trains, buses, even buildings with their beautifully rounded frontages, and trucks. Here are a few sleek old haulers, some depicted in their original settings, that might keep you endlessly amused.  ...
To intercool or not to intercool?

To intercool or not to intercool?

But first an amusing brief story involving a BBC, an intercooler, and Freon. By Sam Logan “I’m no authority on intercoolers,” admits performance carburetor specialist Dale Cubic of CFM, “but I do recall a memorable moment five years ago that involved one. Nothing too scientific,” he adds; nonetheless, it seemed an anecdote worth telling. The noted carburetor specialist had visited an engine builder’s shop with a carburetor for a 1600hp 565ci supercharged big-block Chevrolet. The engine was already installed on the dyno and suspended above it an intercooler. Unsurprisingly, with the intercooler connected, the engine improved by 50–80hp. But then the engine builder unexpectedly produced a can of Freon, purchased from a local parts store, and reached up and sprayed some of its contents over and around the intercooler. He then hastened to the dyno room and made a pull. “It gained a further 40hp! Spraying Freon on that intercooler was like feeding it with nitrous oxide,” remembers Cubic. But the mischief didn’t end there, to further mark the occasion it blew the plumbing off the supercharger! The engine was powered by a small Dominator and a Stage II ProCharger and the Freon had condensed the charge sufficiently to pack in more air than anticipated. Intercool or not to intercool? Racers, by instinct, explore every avenue that might lead them to more power. They know that the introduction of compressed air to the cylinders generates heat and excessive heat provokes early detonation. The common solution for expelling excessive heat is to install an intercooler. But what about hot rodders who enjoy most of their driving pleasures at part-throttle on...