We've come a long way, baby....
We've come a long way, baby. This 1982 shot of the DiGard race team was shot just before the birth of Circle Track magazine. Larry Wallace, who worked in the engine department at DiGard at the time, remembers it as a time when creativity was king but building an engine that could withstand a 500 mile stock car race required many hours of tedious prep work.
Critics of stock car racing often use the familiar complaint that we are still racing using 1950's technology-namely carburetors, flat-tappet lifters and cam-in-block V-8 engines. Of course, you could argue that this "outdated technology" very regularly produces the best auto racing to be found in any form. And that includes the circle track racing done on Saturday nights as much as the Nextel Cup guys racing on Sunday afternoons.
But that also ignores the fact that there actually has been quite a bit of innovation in engine technology in stock car racing. Seeing that this issue marks Circle Track's 25th anniversary, we decided to consider just how much has changed in the way stock car racing engines have been built in the past quarter-century. And to get a better picture, we went to some of the top names in the industry who where there in '83 and are still plying their trade today. Three of our informal panel are engine builders, but then to get a different perspective we also went to a manufacturer, Scooter Brothers of Comp Cams.
In case the names don't ring a bell, here's a quick-hit list of our panel:
Doug Yates - Owner of Yates Racing, Co-owner of Roush-Yates Engines
Keith Dorton - Owner/lead engine builder at Automotive Specialists, which specializes in Hooters Pro Cup, but has built everything from Cup to Hobby Stock
Scooter Brothers - Owner Comp Cams
Larry Wallace - Former lead engine builder for Penske Racing South, currently owner of Larry Wallace Racing Engines which specializes in Dirt Late Model
Advanced testing equipment...
Advanced testing equipment was available in the '80's, such as this early "Spintron" setup by the one and only Smokey Yunick, but it was incredibly rare, and almost always home-built. Today, such equipment is available and widely used by engine builders at just about every level.
The thing, I think, that has changed the most is the engine builder used to be a design development guy, a quality control person, an engine assembler, the track tuner, and really everything in between. And as we've grown in Nextel Cup racing, the business has become a lot more specialized, where now, we have specific guys for each job. It may actually be a bit to the extreme where we have entire quality assurance departments.
That specialization has allowed the rate of development to grow very fast, however. In past years, if you picked up 10 horsepower during the offseason, that kind of carried you all year long. But now, you have to continually improve your engine all year long or you can get behind. You may have to make three or four running changes to your engines during a year. The rate of development has really accelerated over the years as this sport has grown.
Twenty-five years ago, most Cup engine shops only had five or six guys working in them. And even though each of those guys may have had his own specialty, if you gave them enough time, just about every guy in the shop could give you a completed engine on their own. Now, it's more like a Detroit assembly line. You may have 50 employees, but there may not be five or six guys in the entire building that can take the raw materials and give you a complete engine. That's not to say that what they are doing now is necessarily bad, because what the Cup guys are doing every Sunday is just tremendous. But it definitely takes a different mindset to go to work every day and just work on one small component of the engine over and over. That's why I think a lot of the old guys, like myself, got out and started building engines for other series, where we can see a project from start to finish.
Engine builder Keith Dorton...
Engine builder Keith Dorton dug up a pretty interesting comparison between connecting rods used now (left) and then (right). Incredibly, both are for Dodge race engines and both are designed to withstand approximately 500 horsepower. The new rod is from Carrillo and designed for use in a Late Model or similar racing class while the older rod was used in Cup racing.
Back then, we weren't as concerned with weight. Actually, we thought it was necessary to keep an engine together for a 500-mile race. Even on the Cup side, we were using a connecting rod built for a battleship. It was just way overkill, but they were built to work with a really heavy piston on top of it, too. If somebody involved in engine building 25 years ago was in a coma and saw what we are doing now, they'd think there is no way it would last. But we've learned a lot about how to make a lightweight part stiff, and that lighter weight can not only help engine speed but also durability if you use it smartly. I think in '83 we were using a 700 gram connecting rod, and now we are using a 400 gram rod, while at the same time making 40 percent more power with 30 percent more rpms.
Here's a comparison of the...
Here's a comparison of the pistons designed to go on the rods we showed you above. This time, the older component is on the left while the modern piston from Mahle is on the right. Besides the obvious difference in weight (remember, both are designed to withstand approximately 500 horsepower), the new piston also has the advantage of smaller skirts to reduce friction, a smaller wristpin to reduce weight, more accurately cut valve pockets and ring lands, a coating on the skirts to reduce the chances of scuffing, and gas ports in the ring lands to provide excellent ring seal, even with low-tension rings. The notch in the top of the older piston is for spark-plug clearance, which Dorton said killed the efficiency of the flame travel.
Only just in the last decade has there been the wealth of components made specifically for racing that we enjoy now. Twenty-five years ago, it was a lot more work to prep everything before you could assemble the engine because so many parts had to be modified. Things like pulley brackets were a big pain. You wouldn't think about them now because companies like CV Products make so much stuff specifically to work in racing conditions. But then, you either had to modify your brackets and pulleys or fabricate them yourself, because the stock stuff was just about the only thing that was available and it just wouldn't hold up in a race. And believe me, it was really frustrating to drop out of a race because something stupid like an alternator or power steering pump bracket broke.
The internal components required a lot of effort. I remember having to use stock connecting rods. We would use an aftermarket bolt, remove all the flashing and shot peen every one. Twenty-five years ago, we had gotten into aftermarket crankshafts and rods, but the parts were still heavy. We'd take the Ford crankshafts and turn the journals down to Chevrolet size (2.100 inch), and use Chevrolet rods in it because they had a smaller bearing and were lighter.
Because you had to do so much work to each part, it took a lot more time to get an engine right. Now, we can get the right crankshaft with the right weight and dimensions, and it also comes balanced pretty close. Pistons and rods arrive in a matched set, and if I find a rod that's out of balance, instead of grinding on it, I'll send the entire set back. If you know what you need, being able to order exactly what you want makes the required manpower to build an engine approximately 20 percent less than what was required back then.
Back then, you just had to take for granted that you were going to have to modify just about every part that went into a race engine. I remember we used to use a TRW titanium valve. That thing was huge-it was a slug. We'd have to put it in a manual lathe and cut it down. We'd profile it and then cut the stem down. We were basically making our own valves, and each one had to be cut like that on a manual lathe.
Twenty-five years ago, race engine builders had so many needs that you could get into the parts business and be successful just by filling in the gaps. That's changed with a lot of competition today, and being successful requires producing well-designed components that really make a difference. As we've gotten better at tooling and inspection, we've been able to produce better parts with less cost, and the racers have really been able to benefit from that. The neat thing about being in the racing business right now is that with the right idea and a little tenacity, you can go in and do things in a race engine that you never could before. The tools and technology are just that much better.
I think the valvetrain in particular has been the area of greatest improvement. When I first started, we lifted the valve 0.500 inch, and now it's approaching double that. In that time, we've developed a lot of components that have made their way down to the Saturday night guy. The first thing that people looked at was the pushrod. I remember my father (legendary engine builder Robert Yates) telling stories where they had to go with really small, lightweight pushrods at Holman Moody. And now, it has come to the point where the key to the pushrod is stiffness, not weight. The diameter and wall thickness has increased dramatically in order to make the pushrod as stiff as possible.
Another big advancement in the valvetrain is the diameter of the valve, although that has gone in the opposite direction. The perception in the old days was that the only way to make the valve strong enough was to make it really big and heavy. What we've found out is how to make them lighter and stiffer, and that has really just come through some of the advanced testing equipment that has been developed.
A big reason we've been able to push the pace of development, whether it's the valvetrain or any other part of the engine, is the improved testing equipment that has been developed. In our business, durability is just as important as peak power. We have engine dynos that are able to simulate an entire race, so we can get an accurate idea how well something will make power not just on one dyno pull but over a 500-mile race. In the past, we had to put it into the car and hope for the best because the racetrack was also your test bench. Being able to use some type of a test bench to separate your R&D from your racing really helps with the results.
We're still racing solid, flat-tappet camshafts and lifters, but they have made tremendous improvements over the years. Twenty-five years ago, in many applications, we were still using stock core castings for the camshafts and stock lifters. That really limited the power you could make, and the longevity wasn't good, either. Flat tappets have their limitations, but some of the manufacturers have really been able to squeeze quite a bit out of them. But that has come at the expense of cost, of course. The durability has been helped by improvements in materials used and the tolerances the components are held to, but you are going to pay for it.
This is an undated photo of...
This is an undated photo of Robert Yates holding one of the famous "Yates" cylinder heads used for years by Ford Cup teams. Larry Wallace says this head was born from an ability and willingness to experiment with every part of a race engine-including valve angles and locations.
We probably spent more time porting cylinder heads than working on any other single component. That was because back then, there was no such thing as CNC equipment, and everything had to be done by hand. Once the aluminum cylinder heads came along, they were easier to cut, but the raw cylinder heads were still pretty much a cube of aluminum. You could barely fit a crayon inside the intake port.
It was definitely more fun for me back in '82 and '83 because there was so much creativity involved. At the time, I was working at DiGard with Robert Yates and Bobby Allison was driving. As time went on, we started finding more ways to modify the cylinder heads. Then, later on, when we went to the Ford deal at Harry Rainer's with Robert, it really took off. We'd take the standard Ford cylinder head and start welding it up so we could cut it up even more. Then, we'd move both the valve angles and locations. The more we'd find, the more we'd change, and it got to the point where we'd come in in the morning and say, 'OK, where are we going to put the valves today?'
That Ford head was a canted valve configuration, so it looked like it was blown up anyway. So, when we started moving the valves around, they really didn't notice it-plus it didn't say anything about it in the rule book. That, of course, was the beginning of the Ford Yates head they raced for so many years.
Today, you can complete a head so much faster because you can put it on a CNC machine and let it go to work. A CNC is also really good because it is so consistent. But I still think there is something lost because a classic head porter has gotten so rare. He's the one sitting around working on a port every day, and while he's working, he's thinking-coming up with new ideas and things to try. They are a different breed of people, the old head porters.
One big advancement that didn't...
One big advancement that didn't exist in 1983 is performance coatings like this DLC coating on this wristpin (right), which significantly reduces the chances of the pin galling inside the pin bores in a dry-sump engine pulling a lot of crankcase vacuum.
Coatings are another area that has really improved performance. When we first started really sealing up the engine and pulling a lot of vacuum, we couldn't get an engine across the dyno and to the track to test. We started using piston and pin oil squirters, and we actually had to vent the bottom end of the engine. But what really helped solve the problem was the development of DLC (diamond-like coating) on the wristpins. That really helped stop the problem we were having of the wristpins galling to the pistons. Without that coating, we wouldn't be where we are today with the power we can make pulling vacuum in the crankcase. Other coatings have also helped in other areas, but that is the big one to me.
One thing I will say that has gotten tougher, is the demands a racer will make. You could go to any racetrack 25 years ago, and you might find four or five cars capable of winning. Whether it was Nextel Cup or a local dirt track, the difference in lap times between the First-place car and the Last-place car might be a second-and-a-half. Today, there are usually 14 cars capable of winning in just about every division at any track you go to. And then, the difference in lap times between the top car and the tail of the pack may be 0.4 second.
The competition has really improved, and that's a good thing. I'm glad to see it, but that puts the burden back on the engine builders. The rules are so strict that we're all running the same stuff, so you really have to think and work hard to find any little advantage you can get.-Keith Dorton
Doug Yates (right) speaks...
Doug Yates (right) speaks with his father, Robert, in one of the RYR dyno cells. Doug says the development of advanced test equipment has allowed engine builders the freedom to experiment, without the fear of having to test untried components on the racetrack and contributed significantly to the sustained level of progress we've seen in engine technology in the last decade.
A lot has changed in the motor biz in the 25 years that Circle Track has been around. With competition as tight as ever in all forms of racing, it's a safe bet that engine builders around the country will be constantly refining and reinventing better ways to make more power. Where will it go in the next 25 years? That's anybody's guess, but stick with us and we'll find out.