Engine Failure Analysis - 21st Century Detective Work

In racing, failures are going to happen. That's simply the nature of the beast when you are constantly trying to push equipment harder and faster than it has ever been before. Stuff breaks. The question is: What are you going to learn from it?

For both racers and engine builders, good failure analysis practices are often what separate the winners from the also-rans. Like we said earlier, everybody breaks stuff. But how much do you learn from your failures in order to eliminate them in the future?

For example, one engine builder once told us of a blown engine that definitely originated as a connecting rod failure. In order to eliminate the possibility of this happening again in other engines, plans were made to upgrade to a heavier (and more expensive) connecting rod right away. But after a second, closer inspection of all the rods, it was discovered that the problem wasn't really with the connecting rod at all. Instead, the problem came from a new rod bolt that the engine builder began using that was considered an upgrade.

If you looked at the rod bolt in isolation, there was nothing wrong with it. The new rod bolts were, in fact, an upgrade over the old bolts. The problem was with a poor fit between the new bolts and the connecting rods themselves. It turned out that the new bolts featured a head that was slightly wider in diameter than the old bolts by just a few fractions of an inch. But it was enough that it was hitting the chamfer at the edge of the flat spot machined into the rod caps for the bolt. When the rod bolts were tightened down and the engine run, it created enough stress to cause a stress fracture that quickly turned into a broken rod.

As a result of improved failure analysis, the engine builder discovered the real cause of the blown engine instead of the generic answer of "broken connecting rod." By switching back to the original rod bolt, the builder eliminated any further engine failures, maintained better on-track performance by not switching to the heavier rod, and saved a lot of money.

In the "good old days," which weren't actually that long ago, failure analysis of either engine or chassis components often required sending that part off to a dedicated lab or the manufacturer. That meant that quality failure analysis was often quite rare because independent labs cost money and the manufacturer often kept the part.

But now, companies are using technology to produce tools at reasonable cost that were only available to big money outfits just a few years before. Think about the many different options we have now for small, high-definition video cameras that we can mount on and under race cars and get broadcast-quality results. Just a few years ago, only the networks had that type of capability and now cameras like this are readily available for three-hundred bucks or less.

Along those same lines, we recently ran across a new digital microscope that can make doing your own high-end failure analysis easier and more effective than ever. Big C produces the Dino-Lite series digital microscopes, which are used in a variety of industries. Like the new generation of small video cameras, the Dino-Lite digital microscopes are easy to use and quite affordable. After talking with the guys at Big C, they recommended their Dino-Lite Pro as a great option for engine builders. It works with most computers, comes with user-friendly software, features built-in lighting and offers adjustable magnification from 20 to more than 200x. Best of all, the Dino-Lite Pro is affordable for the common guy. You can find it for around $330.

The benefit of using a digital microscope is obvious: you can see details that are hard to make out with the naked eye. But that's something you can do with a strong magnifying glass. A digital microscope like the Dino-Lite has other advantages that we can see being useful to an engine builder or race team. For example, all the images are displayed on a computer screen instead of using a traditional optical eyepiece. Because of this setup, the software has built-in options for using the computer to record the images the microscope gathers. These pictures can be incredibly useful. You can email them to other experts or the manufacturer to get a second opinion on exactly what's going on. Or, you can simply save them for reference later on. Maybe you can get reference shots of the main bearings, the distributor gear or the cylinder walls after each rebuild so that you can watch wear patterns develop and get a better idea of just how long such components can last before they must be replaced.

The Dino-Lite Pro is even capable of producing video. We're interested to try this out for things like checking spray patterns or other carburetor functions as soon as we can develop a secure mounting system. With the built-in lighting system, getting the right exposure is a lot easier than we thought it would be.

While experimenting with our own Dino-Lite for this article, we discovered that engine builder Keith Dorton of Automotive Specialists had many of the same ideas we did and had already invested into a Big C digital microscope of his own. (There are probably others options out there. We know about Big C because the company is actively trying to find ways to make its products better suited to racing.) After talking with Dorton about his experiences with the microscope, he shared with us a few of his experiences and even allowed us to reprint some of the photos he's taken with the microscope. There's more that Dorton is doing with this new technology that he's keeping to himself in terms of maintaining his competitive advantage. But with what we're allowed to share, you should be able to get a pretty good idea of the types of failure analysis you can accomplish with a digital microscope like this, and hopefully, take it further to find ways specifically suited to your needs.