An oil-filter cutter, such...
An oil-filter cutter, such as this one from Powerhouse Products, is a great tool to help you read an oil-filter element to get clues to your race engine's health.
After every race or two, you probably have a list of items to check on your race car. Most likely, you check your brake pads for excessive wear and the rotors for cracks. You may check your suspension components for damage and your ball joints and tie-rod ends for slop and signs of wear.
But what about your engine? If you wait until your driver tells you that something doesn't "feel right" from the driver's seat, it may already be too late. Stock car racing engines do not have onboard diagnostic systems like modern over-the-road vehicles, but that doesn't mean that you can't get clues about your engine's health without tearing it down. Savvy racers and engine builders will frequently look at the spark plugs and occasionally perform a leakdown check on a race engine, which can tell you a lot. But there is another check you can easily perform that will help you determine your engine's health. Hopefully, it will help you catch a developing issue before it becomes a full-blown (and expensive) problem.
This is a wire-screen filter...
This is a wire-screen filter from an engine dyno, and it's easy to see how much "stuff" floats through the oiling system on a new engine build. This is the accumulation after KT Engine Development ran two new race engines on its dyno. (The screen is usually cleaned after every dyno session, but it wasn't cleaned this time so that the buildup would be easier to see.) Much of what you see here is lint from cleaning rags and other harmless matter. The amount of material that gets trapped in a filter should dwindle to virtually nothing in a healthy engine after the break-in process is complete.
It's definitely messy, but inspecting the particles your oil filter has trapped can be a valuable diagnostic tool for the smart racer or crew chief. Race teams running a dry-sump oiling system have been doing this for years, and the external oil tank makes it easy to install a wire screen filter to simplify and expedite the process. For racers in lower classes, where the more common wet-sump oiling systems are mandated, reading the oil filter is a little more difficult; but it certainly is no less useful. This is because the oiling system in any automobile engine not only provides lubrication, but also picks up any trash, contaminants, or shredded race parts. If small enough, any metal that has been shaved off of a component, or even chunks from a broken component, will eventually find its way to the oil filter if it doesn't become embedded in the bearing babbit. Inspecting the "stuff" that gets trapped in your oil filter element can give you a very accurate idea of what components, if any, are failing inside your engine.
Cut 'Em Up Almost all wet-sump race cars use a modern canister-style oil filter. This is true whether you have a remote filter mount or the filter attaches directly to the engine block. The biggest problem with inspecting the filter element inside a canister filter is simply getting the thing open. The canister-style filter is encased in stamped metal, which is quite durable, in order to prevent leaks. When attempting to get to the filter element, it can be tempting to simply go at the metal canister with a pair of tin snips. You should avoid this urge because while you will eventually succeed, you are assured to make a tremendous mess, and the likelihood of getting a nasty cut (complete with motor oil in the wound) is high.
KT Engine's Nathan Allmond...
KT Engine's Nathan Allmond places a canister-style filter into the cutter. Regardless of how much oil you've already drained from the canister, you'll still make a mess when cutting open a filter.
A few companies, such as Powerhouse Products, produce cutters designed specifically to open a canister-style oil filter as painlessly as possible. While there is no way to make opening your old filter completely mess free, a purpose-built cutter is definitely faster, safer, simpler, and less messy.
With a new race motor, you should definitely inspect your filter media after break-in and after the first race or two. But once an engine is broken-in and showing no signs of trouble, this isn't necessary. You can safely back off on the frequency and only inspect your filter media at the same intervals you change your oil filter. After all, filters are too expensive to be cut up unnecessarily.