Author Archives: RM@dmin

Tech Talk #68 – Playing With Fire

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The bad fires are the ones that happen away from the race track.”

Last year I watched my neighbor’s house burn down. I don’t mean he had a barbecue fire that singed his hamburgers. No, he had a blaze that took the house right down to its foundation. A small fire that began as a short circuit under a deck quickly became an inferno when it reached the chemicals and solvents that were stored in the garage. Fortunately no one was injured, but the house was left in cinders.

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Tech Talk #67 – The Hidden Cost of Free Horsepower

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“For sportsman racers, using low-viscosity oil is a lot of hassle, expense, and risk for a few horsepower.”

There are two paths to improving engine performance: increase efficiency or reduce parasitic losses. An engine is like a balance sheet – the power produced by burning fuel is an asset, while internal friction, pumping losses and windage are liabilities. The difference between the power produced in the cylinders and the total losses is the engine’s net output.

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Tech Talk #66 – Go Big or Go Home

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Increasing cylinder bore diameter is the proverbial free lunch – and for once, it really is free.”

Is bigger always better? It depends on the circumstances. A bigger transporter, a bigger horsepower number, or a bigger budget is usually a good thing in motorsports. But a bigger mortgage, a bigger gas bill, or a bigger headache is not usually desirable.

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Tech Talk #65 – The Right Tool for the Job

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“There are several tools that I consider absolutely essential for racing.”

I can’t remember how many cars, trailers, and trucks I’ve owned since I started racing. Most of them are long gone, but I still have many of tools that I used in the back room at Mansfield Auto Parts when I first started to mess with engines some 40 years ago. Good tools are an investment that lasts a lifetime.

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Tech Talk #64 – Why Stuff Happens

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“If a racing part never fails, then it’s probably too big, too heavy, or too slow.”

Washing machines, refrigerators, and pickup trucks come with warranties. Race cars don’t. You can get reliability ratings on televisions, lawn mowers and bicycles from Consumer Reports. You can’t find out how reliable a racing engine is from a magazine.

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Tech Talk #63 – Spare the Rod and Spoil the Engine

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Connecting rods tend to be taken for granted – until they break.”

Imagine riding an elevator that makes a 10-story round trip 7,000 times a minute, alternately stretching and compressing its occupants with every cycle. That’s exactly the kind of punishing treatment a connecting rod endures. A connecting rod must bear the compression force of thousands of pounds of cylinder pressure, withstand the tension loads produced by the piston’s inertia at TDC, and survive the bending loads that try to push the piston through the cylinder wall.

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Tech Talk #62 – The Truth Isn’t What It Used to Be

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“If you want to move forward, you have to look where you’ve been.”

In the 11th century, it was a fact that the world was flat. Any medieval scholar, astronomer or captain could affirm the self-evident truth that the Earth was the center of the universe and that anyone who ventured too close to the edge would fall off into the abyss. It wasn’t until centuries later that skeptics like Copernicus, Galileo and Columbus reasoned that our world was actually a tiny globe orbiting a distant star. Reality hadn’t changed, but people’s perceptions did.

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Tech Talk #61 – No Compromise? No Way!

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The best racing engine is usually the one that has the best set of compromises.”

There is a widely held belief among racers and fans that a racing engine is a no-compromise design. Auto manufacturers must balance the conflicting demands of performance, fuel economy, emissions, long-term reliability, smoothness and cost when they design an engine for mass production. In racing, the requirements are pared down to the basics: power, reliability, legality, and affordability

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Tech Talk #60 – How to Beat the Heat

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“On a blistering summer day, it’s unnecessary to warm up an engine excessively.”

As a Texas resident and taxpayer, I know about long, hot summers. Long before anyone on TV talked about global warming, I was enduring month-long sieges of 100-degree heat. Without the advent of air conditioning, Dallas would probably be just a sleepy gas stop on Interstate 20.

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Tech Talk #59 – Planning for Performance

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“We’re making more than 1300 horsepower with engines that were originally designed to produce perhaps 400 peak horsepower.”

Whether you’re remodeling a kitchen, coaching a basketball team, or racing for a championship, you’ve got to have a plan. In my last column, I wrote about the importance of the fun factor in drag racing. For the vast majority of racers, it’s not about the prize money – it’s about the enjoyment and personal satisfaction that comes with a fast run, a perfect reaction time or a round win. Developing a plan – and then sticking to it – is the key to maximizing the fun and minimizing the cost of racing.

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Tech Talk #58 – Just for Fun

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The reality is that racing is a form of recreation for most participants.”

I don’t know whether absence truly makes the heart grow fonder, but I do know that it changes your perspective. After living on the front lines of the Pro Stock wars for nearly 30 years, I’m now enjoying some time away from the trenches. While I still respect the intensity of the competition in Pro Stock, I’ve gained a new appreciation for a side of our sport that’s sometimes overlooked by professionals: Racing is fun.

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Tech Talk #57 – The CNC Fallacy

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A CNC machine can’t distinguish between a good part and a bad part.”

Every decade has its buzzwords. In the ’30s, it was “streamlining;” in the ’50s, anything “atomic” was cool (except perhaps The Bomb). The ’80s were all about “turbo”, and ’90s were the Digital Decade. For many drag racers, the buzzword for the 21st century is “CNC,” an acronym for Computer Numerical Control.

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Tech Talk #56 – How to Avoid the Hop Up Trap

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“An engine is never worth more than when it’s assembled and running.”

Anyone who flies enough miles in airplanes or stays enough nights in hotels eventually qualifies for “free” upgrades. Of course, these upgrades come with a price – they’ve been paid for with time, money and the aggravation of life on the road. With a new racing season about to begin, many racers are thinking about upgrading their engines – but like first-class seats and hotel suites, there’s a price to pay for an upgrade.

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Tech Talk #55 – Keeping Cool

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Some racers have the mistaken belief that antifreeze improves cooling efficiency.”

With winter fast approaching, it’s the time of year when people start thinking about preparing their cars for cold weather. Anyone who lives in the Snow Belt knows that antifreeze is an essential part of winter survival. But I’m going to make the recommendation that you should never use antifreeze in a drag race engine.

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Tech Talk #54 – The Spark of Life: Ignition Systems for Sportsman Racers

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The most important electrical tool a racer can own is an ohmmeter.”

The combustion triangle we learned in science class defines an engine’s three essential needs: fuel, air and spark. If any of these three items are inadequate, the engine can’t achieve its maximum performance potential. I’ve written columns about fuel systems and airflow, but I’ve not previously addressed the importance of a reliable ignition system in drag racing. This month I’ll try to fill in that missing leg of the combustion triangle.

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Tech Talk #53 – Big Bore or Long Stroke: Which Is Better?

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“An engine produces peak torque at the rpm where it is most efficient.”

Recently I’ve had several conversations with racers who wanted to build engines with long crankshaft strokes and small cylinder bores. When I questioned them about their preference for long-stroke/small-bore engines, the common answer was that this combination makes more torque. Unfortunately that assertion doesn’t match up with my experience in building drag racing engines.

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Tech Talk #52 – Aerodynamics for Everyone

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A smaller, slicker car is the best of both worlds.”

Although I’m an “engine guy,” I’ve been around racing long enough to gain a working knowledge of aerodynamics. I’m also an avid amateur pilot, so I’ve developed an eye for airflow. While I don’t have formal training in the science of aerodynamics, I can look at a race car or a Cessna and come up with a fairly accurate notion of its aerodynamic characteristics.

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Tech Talk #51 – Crank Calls, Part II

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Under most circumstances, a cross-drilled crank is going to cause big problems.”

There’s big money in sequels. Just ask George Lucas; he’s managed to extend the Star Wars series to nine movies. Unfortunately I don’t think this second installment of my two-part column on crankshafts is going to challenge Revenge of the Sith at the box office. After all, a crankshaft is just not as exciting as a light saber.

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Tech Talk #50 – Crank Calls

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“These choices have serious consequences when a 75-pound chunk of machined steel is spinning in the heart of an engine.”

Once upon a time, a 454-cubic-inch engine was considered a big motor, and anything over 500 inches was referred to in awe as a “Mountain Motor”. But like Big Gulps and the budget deficit, everything is bigger in the 21st century – especially drag racing engines. While we’ve run 500-cubic-inch engines in Pro Stock since 1982, the rest of the drag racing world has adopted 600ci, 700ci, and even 800ci motors.

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Tech Talk #49 – Wrist Pins and Unintended Consequences

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“As power levels have escalated, many racers are using wrist pins that are just too light.”

I come from a family of teachers, so perhaps I’m genetically programmed to stand in front of a classroom. Maybe that’s the motivation behind the engine building classes that we conduct regularly at Reher-Morrison Racing Engines. What I’ve discovered, however, is that a teacher learns as much from the students as the students learn from the teacher.

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Tech Talk #48 – The Fundamental Things Apply

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Why does an engine with standard parts run better than one with all of the latest tricks, gizmos and gadgets?”

Sometimes technology can go too far. I recently purchased a cell phone that came with an instruction manual as thick as a brick. I use a telephone for one reason: to make calls. I didn’t buy a cell phone to play video games, take fuzzy photographs, download disco music, get directions to my house or monitor the stock market.

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Tech Talk #47 – Raising the Redline: Why RPM Matters

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“I’m excited about the emerging trend toward fast sportsman drag racing.”

Looking back at the 2004 season, I can attribute much of the performance improvement in Pro Stock to faster engine speeds. It’s difficult to believe that 500cid Pro Stock engines now routinely turn 10,000 rpm, but the truth is plain to see on the data recorders and on the time slips.

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Tech Talk #46 – The Simulation Situation

By Darin Morgan, Reher-Morrison Racing Engines
DARIN MORGAN, author of this issue’s Technically Speaking column, is in charge of cylinder head research and development at Reher-Morrison Racing Engines.

“Comparing the Space Shuttle to a racing engine may seem like a leap, but in fact the underlying variables in an engine combination are equally mind-boggling.”

With four national events in four weeks, including two round trips to Maple Grove Raceway, David Reher has been spending more time sitting on airplanes than on writing his column for National DRAGSTER. David asked me to pinch hit for him in this issue, and since my subject is computer simulation, you might think of this as a simulated David Reher article.

Engine simulation software is a hot topic in the automotive industry. Sophisticated programs such as WAVE and MANDY cost millions of dollars, which limits their customer base to auto manufacturers and Formula 1 teams. For the rest of us, there are engine simulation programs with prices that range from less than $100 to several thousand dollars.

I admit that I’m addicted to engine simulation software. I’ve played with numerous programs, and I’ve spent hours running “what if?” scenarios. But as a professional engine builder, I also understand the limitations of these programs. Unfortunately, some racers don’t.

In my conversations with simulation software designers and code writers, I’ve learned that these programs were never intended to design an entire engine. Rather, their primary objective is to note specific trends of individual changes. In other words, a program can tell you with reasonable accuracy what the likely result will be if you change the bore, stroke or runner length in a Corvette LS1 engine. It can’t tell you how to build a Quick 16 engine from scratch.

My specialty at Reher-Morrison Racing Engines is cylinder head development. I’m frequently asked about equations or formulas that can determine specific engine design criteria. Customers want to know how to calculate the perfect port volume for an engine, how to select the ideal intake manifold, or how to determine the optimum valve diameter for a runner. They want a magic formula that explains how a racing engine works – but such a shortcut simply doesn’t exist.

Consider the Space Shuttle. It’s just an airplane with rocket motors, right? But when you look into the details of launching, flying and recovering the Shuttle, it becomes apparent that this is a task of mind-boggling complexity. The variables are almost infinite.

Comparing the Space Shuttle to a racing engine may seem like a leap, but in fact the underlying variables in an engine combination are equally mind-boggling. If you don’t understand what these variables actually do, it’s tempting to plug numbers into a simulation program until you get the results you want. One likely consequence of this approach is to design an engine that’s not applicable in the real world.

Here’s an example. Recently a racer questioned me about all of the components in one of our Super Series bracket racing engines. I gave him the information he requested, and he modeled the engine with a simulation program. His results were fairly accurate, with an error of about 2.5 percent (20 horsepower), which I thought was reasonable. But the software stated that if the exhaust duration were increased 10 degrees, the engine would gain 25 additional horsepower. I just wish it were that easy!

We’ve built and dyno tested dozens of these engines. They’ve logged thousands of runs on drag strips. Now a customer tells us that we left 25 horsepower on the table. But what the simulation software didn’t allow him to do was input the discharge coefficient of the exhaust port. In other words, the program didn’t “know” the design specifics of the exhaust system. It based its calculations on simple airflow, and therefore didn’t have enough information to generate a realistic answer.

You still need experience and knowledge to get it right. The more complicated the software, the more essential this real-world database becomes. When dealing with ultra-high performance engines, the details become so subtle that no software can simulate them. In a high-end racing engine, a tiny change in the approach to the valve seat or the contour of a piston dome can produce a measurable difference in performance on the dyno and on the drag strip. Even Ferrari, with its whiz-bang Formula 1 simulation software, still has to build, test and validate any change in hardware before taking it to a race.

It’s a mistake to put blind faith in a computer program. Some programs are certainly more accurate in their predictions than others, but they all have shortcomings. Building an engine on a computer screen is no substitute for bolting together the parts and running it down a track. To my knowledge, a virtual engine has never won an NHRA national event.

Tech Talk #45 – Where to Find “Free” Horsepower

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A little oil consumption is a good thing because it indicates that you’re right on the edge of the minimum required ring tension.”

I’m told there is no free lunch, but I am certain there is free horsepower to be found in many racing engines. What I define as free horsepower is increasing an engine’s output by reducing parasitic losses such as oil windage and internal friction. Piston rings and oil systems are two interrelated areas where you can often find horsepower without changing the basic engine combination.

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Tech Talk #44 – Summertime Blues: How to Live with Bad Air

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Some racers wear out the threads on their carburetors trying to adjust for weather conditions.”

As I write these words, we’re loading our Speedco Pontiac Grand Am into the transporter for the annual trek to Denver. Preparing to race at a mile above sea level brings home the reality of racing under adverse conditions. While we make many adjustments for Bandimere Speedway, one of the items that is definitely not on our to-do list is to change carburetor jets.

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Tech Talk # 43 – The Trouble with Flat Tappets

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A low-tension valve spring and a heavy steel valve is the worst possible combination for high-rpm reliability.”

Faithful readers of this column know that my mantra on engine building is to spend your money wisely. Sometimes that means writing a bigger check initially in order to save money in the long run. A case in point is the decision whether to use flat tappets or roller lifters. In my view, a flat tappet is a ticking time bomb in a racing engine. Sooner or later, that bomb is going to explode with expensive results.

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Tech Talk #42 – Spin to Win: Valvetrain Revelations

DavidTechArticlesBy David Reher, Reher-Morrfison Racing Engines

“The valve spring is like a canary in a coal mine – it will usually signal a developing problem before a catastrophic failure.”

When Galileo pointed his handmade telescope at the planets and became the first human to behold Jupiter’s moons and Saturn’s rings, he saw something that had been invisible. Of course these moons and rings had existed for millenia, but they were beyond human perception until the invention of a device that could magnify the faint images. Like Galileo’s telescope, tools such as dynamometers, wet flow benches, and data recorders have given drag racers the ability to “see” events that would otherwise be imperceptible to human senses.

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Tech Talk #41 – Security Clearance: Measuring Piston-to-Valve Clearance the Right Way

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Not everyone may agree with our technique, but I am convinced that it is the best way to achieve accurate results.”

With apologies to my sister the veterinarian, there is more than one way to skin a cat and more than one way to measure piston-to-valve clearance. I’m not an authority on cat skinning (nor do I want to be), but I do know about the importance of proper valve clearance in a racing engine. I see hundreds of engines come through our shop every year, and I’m alarmed by how many engines assembled by do-it-yourself builders have incorrect piston-to-valve clearance.

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Tech Talk #40 – Wet Flow Revelations: The Monsoon Inside Your Motor

By Darin Morgan, Reher-Morrison Racing Engines
DARIN MORGAN
, author of this issue’s Technically Speaking column, is in charge of cylinder head research and development at Reher-Morrison Racing Engines.

“We felt like blind men who had been given the gift of sight.”

If you expected to find David Reher’s column on this page, I hope you won’t be too disappointed to find my words here instead. I’m in charge of cylinder head development at Reher-Morrison Racing Engines, and David asked me to write about the extraordinary impact of wet flow testing on our R&D program. I’ve given presentations on our wet flow development at the Performance Racing Industry (PRI) trade show and the Advanced Engine Technology Conference. Since most National DRAGSTER readers can’t attend these events, David thought that Technically Speaking would be a good way to spread the news. He also promised that he’d be back on this page in a few weeks.

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Tech Talk #39 – Bolt-On Admonitions

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Building a racing engine is like painting a car – the preparation takes far longer than the final act.”

Walking through the aisles in a supermarket can teach you more about marketing in the 21st century than a business school textbook. It’s easy to see the hot buttons that the experts have determined will trigger a purchase decision for anything from breakfast cereal to dog food: “New!” “Improved!” “Natural!” “Low Fat!” “Low Sodium!” shout the packages. It takes a skeptical consumer to recognize the hype behind the words. Yes, a tin of lard is low sodium; that’s because it’s pure fat.

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Tech Talk #38 – The Truth About Tuning

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

I couldn’t tune a piano if my life depended on it, but I have tuned a few engines in my career. The process of tuning is fundamentally the same for racing engines and musical instruments. In both cases, you are making the final adjustments to a complex assembly of precision components. No one tunes a piano with a hammer, but sometimes I see racers take a sledgehammer approach to tuning engines.

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Tech Talk #37 – The Hidden Costs of Horsepower

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

I believe that an informed customer is a better customer. Whether I’m buying a laptop for my daughter to take to college or a new CNC machining center for our shop, I like to know as much as possible about the product before I sign on the dotted line. So in this spirit of full disclosure, I’m going to tell you something you need to know about racing engines: The more powerful the engine, the more maintenance it requires.

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Tech Talk #36 – Dry Sumps for Drag Racing

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A dry-sump oil system is one of the few products you can buy with confidence that it will improve performance.”

According to the informal David Reher telephone poll, interest in fast Sportsman classes is skyrocketing. If the sample of racers I talk to is representative of the sport as a whole, then Top Sportsman racing has a bright future. Interest in this particular style of fast doorslammer racing is spreading as quickly as a rumor on the Internet. The fact that Top Sportsman has been adopted by several NHRA divisions is a leading indicator of the class’ future growth.

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Tech Talk #35 – Warning: Racing May Be Hazardous to Your Wallet

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

Has the world really become a more dangerous place, or are we just more aware of the dangers of everyday life? If I buy a new appliance, a power tool or a treadmill, the owner’s manuals typically have dozens of pages of warnings, cautions, disclaimers and notices before I ever get to the instructions. There are enough stickers in my truck warning me about the possible dangers of air bags, roll-overs and exploding batteries to make me think that driving to work should qualify as hazardous duty. But ironically, the more we are assailed by warning signs, screaming yellow caution notices and clever icons depicting various ways that stick people can be killed and maimed, it seems the less attention we pay to them.

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Tech Talk #34 – Chips of the Old Block

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

A strong, dependable block is the cornerstone of every racing engine. It’s the foundation that supports all of your efforts to build horsepower. Yet as important as the block is in building a reliable and powerful motor, too many racers still insist on using a “good old block” as the starting point for a competition engine. In my opinion, that’s a major mistake. The truth is that there aren’t any good old blocks – at least when the subject is big-block Chevrolet V8s.

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Tech Talk #33 – Racing Through the Years with the All-Star Drag Racing Team

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

In the drama of drag racing, drivers are the stars and engine builders are the extras. I understand why the Best Actor at the Academy Awards gets his picture on the front page while the camera operator gets a mention in the final paragraph. After all, no one interviews the winning engine after a final round; it’s the drivers who get (and deserve) the glory.

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Tech Talk #32 – The Quest for the Combination

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

When I first discussed writing the Speed Reading column with the staff at National DRAGSTER several years ago, we agreed that I would focus on engine technology for sportsman racers. At the risk of pushing the editorial envelope, this month I’d like to expand my assigned topic with some thoughts on how chassis and car setups affect quarter-mile performance.

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Tech Talk #31 – To Good To Be True

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

The 21st century has been called the Information Age, but I’m beginning to wonder whether it might be more accurate to call it the Infomercial Age. The advent of long-format television commercials has blurred the distinctions between advertising and reporting. If the production is slick enough, it’s difficult to discern the difference between a sales pitch and a documentary.

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Tech Talk #30 – Reserved Seats

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

It’s the nature of racers to work on things – even parts that may be better left alone. Ingenuity and experimentation have produced power levels that were once thought to be impossible. As a lifelong tinkerer, I confess that I find it hard to resist the urge to mess with mechanical components. Nevertheless, I strongly urge you to resist the temptation to service the valve seats in competition cylinder heads.

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Tech Talk #29 – Security Clearance

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Almost without exception, engine problems are the result of insufficient clearances.”

We are often told to think big if we want to achieve success, but today I want you to think small. In fact, I want you to think about clearances in a racing engine that are smaller than one thousandth of an inch. These minuscule measurements can mean the difference between long life and sudden death for a racing engine.

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