Engine Evolution - 25 Years Of Engines

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 Of course, you could argue that this "outdated technology" very regularly produces the best auto racing to be found in any form.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.

Our Panel
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 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.

Increased Specialization
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.
-Doug Yates

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.
-Larry Wallace

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.

Losing Weight
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.
-Keith Dorton

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.

Custom Components
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.
-Keith Dorton