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 Robert Yates holding one of the famous "Yates" cylinder heads
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 exist in 1983 is performance coatings like this DLC coatin
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