Catch as Catch Can

In days gone by, decoking engine internals was a common task, but as time marched on, fuel injection, emissions control devices, and fuel additives brought that task to a grinding halt. However, the need to manually decarburize engines is back stronger than ever. The drivers of that sharp uptick in this service are myriad.

The principle behind our OE FIX catch can is one that has existed for many years. Catch cans, popularized in the world of high performance, incorporate screens and baffles to help filter the oily mist of blowby gas that is routed to the intake. Our 46110 catch can is a universal item; a performance part built for everyday cars, and we’ve tailored it—curiously, we know—to stock applications. We expect you’ll install it right after you’ve just shocked a customer with the cost to manually clean his intake. But how did we get here? How did Dorman wind up designing a universal catch can as an OE FIX for workaday cars and trucks?

To understand our nuanced solution, you need to understand the whirlwind of complex problems that have cropped up very recently that have made the catch can an indispensable prescriptive item—and why it should be on a lot of the estimates your shop is writing. OE FIX parts aren’t usually so universal, but our catch can truly can reduce expensive manual and chemical carbon removal and bring the cost of owning these vehicles back in line with customer expectations.

Direct injection

Gasoline direct injection is perhaps the most influential contributor to dirty intakes. DI packs a one-two punch when it comes to carbon fouling on both intake and exhaust valves. Fuel that’s injected directly bypasses the intake valves. For years, mechanics knew at the very least intake valves were likely to be clean, since modern, additive-bearing fuel acted as a solvent to wash off any errant oil that had been drawn into the manifold and cylinder head. But with no fuel passing over the backs of the valves, oil drawn into the intake coats the valves and is never washed off. This problem was severe enough that some manufacturers have since elected to add a set of port injectors that fire occasionally to help clean the intake.

DI vehicles also generate quite a bit of soot, due in part to their very nature—fuel doesn’t have a long intake tract where it can tumble and swirl with the air. Instead, since it’s injected at the last second, fuel burns somewhat incompletely. That soot cakes up on the back of the exhaust valves, where engine heat bakes it in place.

If you find yourself cleaning valves and ports on a modern DI engine, it’s highly likely all valves will be rather dirty.

Forced induction

In model-year 2000, fewer than 1% of cars produced were turbocharged (fig. 1). Now, though? You don’t need us to tell you what you see in your bay every day: turbos are becoming as common as bellybuttons. Once the domain of fringe vehicles like diesels and exotica, the turbo has been tapped for its ability to exploit power gains. Because of this, engines are now produced in displacements that would have been unthinkable around the turn of the century. Cylinder pressures—and the resultant blowby—have increased dramatically. All that oil has to go somewhere, and that place is usually into the intake manifold. Our catch can extends the PCV lines, gives the hot gas a place to expand and shed heat, and adds surface area for oil to cool, condense, and collect.

Sales of new turbocharged vehicles. Source: S&P Global Mobility

Low-tension piston rings

Reduced friction equates to less power lost, which is the exact reason we have low tension piston rings. However, when coupled with the increased cylinder pressures just mentioned, rings of this design don’t seal the sump from blowby as well, nor do they scrape excess oil from the cylinder walls as aggressively as their counterparts from yesteryear. Our catch can helps intercept that oil before it makes its way into the intake tract.

Thinner oil

10W40? The only place you’ll find that used in 2023 is in a shed next to the garden tiller. Oil weights have trended thinner and thinner to reduce frictional losses and improve fuel efficiency. Customer demand for longer oil change intervals has permitted the widespread use of synthetics, which is how the current crop of 5W20, 0W20, and even 0W16 oils have come to rule the auto parts store shelves. Thin oil is oil that can blow by easily and collect and condense in places it doesn’t belong—like the PCV system and intake manifold. The 46110 uses a two-stage collection system. Oily mist is routed directly into a baffle, which causes oil to collect and uses gravity to separate it. As the gas moves through the can, a 50-micron filter blocks any oil that has circumvented the baffle and also routes it downward into the can.

The OE FIX

Now, if this has all sounded like the perfect storm to you, it is. Manually and chemically cleaning intakes, valves, and cylinder head ports is time-consuming and difficult. It’s a far cry from the days of just popping the top off an old flathead and scraping away. The catch can is elegant in its simplicity and infallibility, exactly why performance-minded enthusiasts have relied on them for years. They’re pretty low-maintenance, too—just empty the can every now and then.

Unlike most catch cans, ours isn’t a flashy piece anodized in a garish color, meant to draw attention to a modified hulk within an engine bay. Instead, we designed ours with a conservative appearance specifically to help it blend in for a factory look, which we know most customers want. And while some specialty setups are built specifically for a particular engine in a particular chassis, Dorman’s included universal mount kit renders the 46110 highly adaptable to most vehicles on the road.

The two mounting brackets and an almost infinite amount of indexing options clearly showcase the engineering employed to make this a snap to install on a breadth of different vehicles. You’ll be hard-pressed to find a vehicle where this installation is difficult if you’re using our OE FIX kit.

The can itself spins off for occasional emptying, and we’ve also incorporated a drain plug into the bottom in case removal of the can from the head is difficult. All the hardware you need to install this is in the box and plumbing one in couldn’t be simpler.

If you’re scraping, soaking, or blasting passages in an intake or cylinder head, sell a catch can. You’ll increase your ticket average and truly help your customer avoid such needless, expensive service so frequently. You can also let them know that by servicing the catch can, they’re taking a proactive step to sidestep these heavy repair bills, all for the modest cost of the kit and your time to install it.

The OE FIX 46110 is meant to be easy to sell and easy to service. It looks professional when installed under the hood, and helps you deliver on a promise to extend time between cleanings and reduce the cost of ownership. When it comes to keeping customer cars running reliably and economically, OE FIX parts really are performance parts.