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. Photo by Jeff Huneycutt
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
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.
-Larry Wallace
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. Circle Track Archive
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.
-Scooter Brothers
Valvetrain
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.
-Doug Yates