Tech Talk

Tech Talk #90 – Pistons and Pressure Spikes

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By David Reher, Reher-Morrison Racing Engines

“The pressure curves explained what I’ve learned about racing engines through years of experience and observation.”

Unless your race car is powered by a jet engine or a turbine, a critical factor in engine performance is the pressure exerted on the pistons. The goal in race engine development is to maximize the cylinder pressure that pushes against the pistons and thereby rotates the crankshaft.

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Tech Talk #89 – The Eyes Inside Your Engine

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By David Reher, Reher-Morrison Racing Engines

“Spark plugs are the best source of information on what’s really happening in the cylinders.”

If you really want to know what’s happening inside an engine, look at its spark plugs. The spark plugs are eyewitnesses to the combustion process, and their expert testimony provides insights into what is really happening inside the cylinders.

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Tech Talk #88 – All That Glitters at the Trade Show

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By David Reher, Reher-Morrison Racing Engines

“CNC is a manufacturing process, not a thought process.”

When the racing season ends, the show season begins. This winter I made the journey to Indianapolis to attend the Performance Racing Industry trade show. After several years in Orlando, the PRI Show returned to its former home in Indy, and it was amazing.

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Tech Talk #87 – Myths and Misconceptions About Power Adders

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By David Reher, Reher-Morrison Racing Engines

“The only source of power in any internal combustion engine is the energy in the fuel.”

The hottest topic in engine building these days is power adders. It seems like every magazine, website, and online forum is talking up nitrous oxide injection, superchargers, and turbochargers. What’s the big deal?

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Tech Talk #86 – Spin and Win: Evaluating Valvetrains the Old-Fashioned Way

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By David Reher, Reher-Morrison Racing Engines

“In my experience, one of the best indicators of valvetrain stability is also the simplest.”

My longtime friend, teammate, and business partner, the late Buddy Morrison, had a direct approach to problem solving. When Buddy wanted to learn about oil control and crankcase windage in a racing engine, he convinced me that it was a good idea to make a dyno run on an engine without an oil pan.

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Tech Talk #84 – Dry Sumps Save Lives

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By David Reher, Reher-Morrison Racing Engines

“In a wet-sump engine, the rotating assembly whips the oil like a milkshake in a blender.”

It’s great to be back in the pages of National Dragster after taking a break from writing columns. I appreciate the many comments from racers and readers, and I’ll attempt to come up with interesting topics now that I’m back on the keyboard. Continue reading

 

Tech Talk #83 – Engines Are Engines

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“I’ve learned that engines with pistons and valves are fundamentally alike.”

I count myself among the fortunate people who enjoy going to work every day. The fact is that I love working on engines – all kinds of engines. After nearly 40 years of messing around with motors, I’ve learned that there are more similarities than differences in various types of engines.

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Tech Talk #82 – The 400-Horsepower Tune-up

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A basic nitrous oxide injection system can make a huge difference in fast Sportsman racing.”

I’ve been around drag racing long enough that I can remember when racers first reached many of the sport’s performance milestones that are being celebrated during NHRA’s 60th anniversary season. There was a time when a 6-second elapsed time was sensational. Don Garlits was so elated to run in the sixes that he famously shaved his beard on the starting line after winning the 1967 U.S. Nationals. Today, however, six-second runs are commonplace – and they have become the price of admission in fast sportsman eliminators like Top Dragster and Top Sportsman.

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Tech Talk #81 – Takin’ It to the Streets

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“It’s astounding to think about driving a car with 1,000 horsepower on the highway.”

One of the recurring themes in automotive advertising is the notion that racing improves the breed of production cars. There’s strong evidence to support that idea, at least in engine technology. Not too many years ago, 300 horsepower was a stout number for a showroom engine. Now it seems that every four-door sedan has 400+ horsepower, and high-performance models have more than 600 horses under the hood.

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Tech Talk #80 – Getting to Know Nitrous

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Something that looks simple from the outside is actually incredibly complex.”

There was a time in my life when I thought that Pro Stock was the center of the universe. I’d spend every minute of the day – and many sleepless nights – thinking about how to extract more horsepower from a 500-cubic-inch Pro Stock engine. Unfortunately, focusing so intensely on one combination can lead to a severe case of tunnel vision. I didn’t appreciate the much wider world of racing engines until I retired from Pro Stock.

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Tech Talk #79 – Are Burnouts Abusing Your Engine?

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“How a drag racing engine is treated during burnouts has a lot to do with its long-term reliability.”

In my recent back-page columns, I’ve focused on the mechanical side of drag racing – cooling systems, lubrication systems, fuel systems, and ignition systems. This time I’m going to address a different topic: How a driver’s burnout technique can affect the engine and chassis.

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Tech Talk #78 – The Big Chill: How to Avoid an Engine Meltdown

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Most drag race cooling systems are utterly inadequate to dissipate such staggering heat.”

An engine has two fundamental needs: lubrication and cooling. Racers typically devote a great deal of time and money to oiling systems, devising windage trays, baffles, deflector screens, and dry-sump systems to ensure continuous lubrication. In comparison, drag race cooling systems are almost an afterthought – and that’s a grave mistake.

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Tech Talk #77 – Back to Basics

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“There are some basic skills that must be mastered to build an engine successfully.”

I traveled backward in time last week. It happened while we were rebuilding a big-block Chevrolet engine. This particular engine won the 1982 NHRA Pro Stock championship, and overhauling it was like firing up a time machine.

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Tech Talk #76 – The Titanium Solution

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Installing titanium valves is simply the best way to improve a racing engine.”

The same properties that made titanium the metal of choice for nuclear submarines and high-altitude spy planes during the Cold War also make titanium an ideal material for engine valves. Depending on its alloy, titanium is 45 percent lighter than steel and twice as strong as 6061-T6 aluminum. Replacing steel valves with titanium is simply the best way to improve a racing engine.

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Tech Talk #75 – Year-End Observations

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A great car setup can’t overcome a bad engine, and a terrific engine can’t win in a lousy car.”

Although it’s been several years since Reher-Morrison Racing Engines last competed full-time in NHRA Pro Stock competition, I still follow the category with interest. The fact that we have expanded our engine business with customers competing in classes ranging from Pro Mod and Top Sportsman to tractor pulls and 400 mph Bonneville land speed racers has given me a fresh perspective. Since this issue of National DRAGSTER celebrates the accomplishments of this year’s Pro Stock champion, I thought I might offer some observations on the state of the class.

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Tech Talk #74 – The Oil Pan Paradox: Power or Reliability?

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The most powerful oil pan is not necessarily the best oil pan for a sportsman drag racing engine.”

It’s an article of faith among racers that there is “free” horsepower to be found in an engine’s oiling system. Reducing windage and cutting frictional losses can indeed improve engine performance. Unfortunately, the unintended consequences of these horsepower-enhancing techniques can be a loss of reliability, followed by a big repair bill.

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Tech Talk #73 – The Pinnacle of Piston Engine Development

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Building better engines was literally a matter of national survival.”

As a professional engine builder and a self-confessed motorhead, the development of internal combustion engines is both my livelihood and my passion. While unlocking a few more horsepower in a racing engine is always rewarding, I recognize that ultimately it’s not a matter of life and death. There was a time, however, when the fate of the world literally depended on engine development.

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Tech Talk #72 – The Price of Knowledge

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Quality is remembered long after price is forgotten.”

Anyone who buys a “Rolex” watch on the Internet for 25 bucks has a pretty good idea that it’s not the genuine article. Producing and selling counterfeit products is a lucrative global business, and it’s not just high-end luxury goods like watches and leather goods that are knocked off. There are black markets for everything from blue jeans to perfume. In the traditional auto parts business, name-brand oil filters, spark plugs, and brake pads have been counterfeited by unscrupulous operators who sell low-quality parts in familiar looking boxes.

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Tech Talk #71 – Racing Through Hard Times

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“Next year, when the weather turns warm and the days grow longer, racers will still be racing, and fans will still be watching them.”

Along with death and taxes, the third inevitability in our lives is change. Certainly the world has been going through some major changes in the last few months, and most were not for the better. But I’m not going to join the drumbeat of depressing news – there’s already a surplus of doom and gloom on television and the Internet. The fact is that racers are going to find ways to race in good times and in bad times.

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Tech Talk #70 – Airflow Fallacies: Avoiding the Pitfalls of the Flow Bench

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“The pursuit of a big cfm number has ruined countless cylinder heads.”

“What’s it flow?”

Whenever a conversation about cylinder heads begins with that question, I cringe. I know where this discussion is going, and it’s not good. When a racer wants to distill the performance of a highly developed cylinder head down to a single number, I know I’m dealing with someone who is fixated on the flow bench.

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Tech Talk #69 – The Land of the Giants

DavidTechArticlesBy David Reher, Reher-Morrison Racing Engines

“A new generation of 800-cubic-inch engines has turned those old Mountain Motors into molehills.”

Back in the early days of Pro Stock match racing, any engine with more than 500 cubic inches of displacement was labeled a “Mountain Motor.” Now a new generation of 800-cubic-inch engines has turned those old Mountain Motors into molehills. Continue reading

 

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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