Of five major threats to a clutch system, what would you consider the most forbidding?

Of five major threats to a clutch system, what would you consider the most forbidding?

Archie Bosman: As you sit quietly reading these lines, a whirl of activity is taking place in the bell housing. Let’s imagine for a moment the clutch assembly could express its greatest anxiety, what might it be? Might it be the use of excessively harsh friction compounds on the clutch discs or inadequate clamping forces causing slippage? Perhaps, extremely sticky tires are the main threat? Enumerating the cardinal sins: Apparently ‘no’, according to Ram Clutches none of these represent its greatest fear…its principal concern would be mass—that is the weight of the car carried into motion by the clutch. A heavier vehicle imposes a greater load on the clutch system than a lighter one. Further perils include poor gearing, improper flywheel mass and, indeed, sticky tires. A high performance car with an inadvisably high rear-gear requires more manipulating of the clutch pedal to prevent it from slipping than one with a lower gear. A higher first gear (lower numerically) is also problematic as it, too, imposes a greater load on takeoff and, furthermore, can be detrimental to the clutch even when it is fully engaged. Linked closely with high first-gear ratio deficiencies is the flywheel. The purpose of the flywheel is to create inertia, which refers to preserving a state of uniform motion that helps to get the car moving. A heavier flywheel generates more inertia and thus makes it easier to accelerate from standstill. It also reduces clutch slipping on takeoff. On the other hand, with a properly geared vehicle, that is one with an appropriately low gear that invites the use of a light flywheel, it will...
How to find a vacuum leak in a gasoline engine

How to find a vacuum leak in a gasoline engine

Ray Bohacz is a journalist in the automotive field and author of CarTech’s book “How to tune and win with Demon Carburetion”. He is also a monthly contributor to Hemming’s Muscle Machines magazine. Additionally, Ray writes short articles for the agriculture industry and is featured in a series of videos as the SF (Successful Farming) Engine Man. His videos are short, informative features which apply to both farm and automotive equipment. Here Ray shows you how to find a vacuum leak in a gasoline...
Pressing on in difficult circumstances: the trouble with racers

Pressing on in difficult circumstances: the trouble with racers

By Vic Moore: ChumpCar has been a well-head of cost-effective endurance competition for the road racer since its founding in 2009. It introduces hours of valuable road racing experience with a special emphasis on long distance driving and affordability. The race cars are converted road-going machines mostly from the nineteen-eighties and nineties with strict cost limits in place to control spending. Competitive Dirt Late Model race cars often consume four sets of expensive racing tires on a weekend unlike ChumpCars that typically run two endurance races on one set of tires by rotating them. The principal safety measure consists of a specified roll bar structure. On the first Saturday of summer, I had come to Atlanta Motorsports Park. A mere seven miles from our office, I was there to compete with the Borg Warner team from Asheville, North Carolina in a 12-hour race organized by ChumpCar rival World Racing League. AMP’s compact 2-mile course is one of contrast. A short straight that runs past the start-and-finish line connects a seemingly unending sequence of undulating third and fourth gear corners. In my ignorance I had wondered why so many drivers missed their apex at Turn One. Now I understood: situated on falling ground it’s almost impossible to see and appraise the tricky turn from a low racing seat! On this occasion five of us would take the wheel of a 1984 Mazda RX7. For the Borg Warner team, who thrive on five or six endurance races each year, preparations had come together by the barest of margins. During Friday testing with ambient temperatures nearing three figures and humidity levels similar,...
Kaase abandons traditional two-piece big-block rear main seal

Kaase abandons traditional two-piece big-block rear main seal

∇ New one-piece seal conceived for use on Ford 429-460 big-blocks; Boss Nine; and P51 engines ∇ Simple assembly; reliable service ∇ See installation sequence below Winder, Georgia: Without wishing to diminish the performance of any current rear main seal for the Ford 385-series engines, Jon Kaase wanted more. “We had to go out of our way to find it,” he says. “In fact, we had to go out of the country—to England—to get the quality we were searching for.” Using the same manufacturing source as the Sprint Cup teams and following several years of testing, the seal makers produced the tooling, the prototype seals and now the production items exclusively for Kaase. This new seal is a one-piece device that replaces the conventional two-piece arrangement. On its face there is a dot—a small indentation—that represents the exact place to cut the seal with a razor blade for installation. Once cut, the seal can be wrapped around the crank and a daub of silicone sealer placed in the joint. Before lowering the crank into the crankcase, apply a light film of silicone to the outer perimeter surface of the seal and rotate the joint such that it is positioned in the main cap. There are numerous causes for rear main seals that leak: insufficient lubrication at the sealing lip edge, shaft roughness, lip hardening, lip softening and so on. But what offends the racers and hot rodders most is the indignity of having to do the job twice, which is often a day wasted if the oil pan cannot be removed without raising the engine half-way out of the...
No arrests yet. Reward tops $20,000.

No arrests yet. Reward tops $20,000.

By Mary Maglone: When Robin Buck, wife of noted engine builder Charlie Buck, recently posted “Can anyone identify these men” on her Face Book page accompanied by photographs of two Caucasian males, she succeeded in recruiting 589,000 individuals in short order. Some responded immediately telling of resemblances to persons seen on the television series Street Outlaws while others cast about assembling a reward in an attempt to catch the criminals. Engine builder Reher Morrison’s recent contribution brought the total to $20, 110. Around 10:30 on the night of Thursday, June 18, 2015, thieves broke into Buck Racing Engines of King, North Carolina and stole eight engines valued at just under $500,000. Earlier that afternoon two unknown men had visited the shop inquiring about a short-block for sale. Their photographs had been captured while in Buck’s office area. Although the intruders occupied the building for five and a half hours, they operated in darkness in the attic for the first two hours with flashlights. Crawling along the floor in military style they inspected the wiring to the alarm and phone systems. Once the two systems were immobilized the intruders either sprayed the lenses of the video cameras with paint or destroyed them. Nonetheless, further concealed cameras continued to monitor their movements as they set about selecting their illicit prizes. Although two of the engines stolen were built for high-performance street cars the thieves focused chiefly on the nitrous-assisted engines, the most expensive of which was valued at $100,000. Interestingly, a supercharged engine remained under their scrutiny for an hour and a half, but ultimately they replaced its covers, deciding against...
Historics: the delights of the G50 and how it was developed

Historics: the delights of the G50 and how it was developed

In production from 1958 to ‘62, the allure of the G50 Matchless was simple: it was a 500cc, air cooled, single cylinder, four stroke machine that was competitive, inexpensive, and easy to maintain. A derivative of the 350cc AJS 7R engine that was created in Britain in the post war 1940s, the G50 returned to prominence in the 1970s when resurgence in national and international classic racing took hold. The engine cutaway picture, prepared by former G50 racer Chuck Huneycutt, who heads the restoration division at the Barber Motorsports Museum, allows viewers a unique insight into most of the functioning parts behind the magnesium Elektron alloy castings. Elektron was used to save weight and the anodized gold finish was used to protect it from oxidizing. Unsurprisingly, under George Barber’s development and racing program of the 1990s the G50 was transformed. With Huneycutt’s influence peak power increased by over 25 percent. The single Amal carburetor was replaced by a 44mm Mikuni VM round-slide-style. Although the original Amal produced slightly more power at full throttle it had a tendency to hesitate while cornering at maximum lean. Most notably, as the compression ratio, engine rpm, and power output increased, the original 35-tonne-steel flywheel, now working beyond its design capability, began to crack. The solution was to replace the original design, a pressed-together crank, with a one-piece style. Further development involved the addition of a second spark plug, which led to a reduction in ignition timing. As a result maximum power occurred at 18 degrees before TDC instead of the original 32-degree setting.  Though in low resolution, the deftness of the G50 can still...