Battle of the Lifters: Flat Tappet vs Roller, Solid vs Hydraulic

Let’s cut right to the chase: We like lifters. They’re something we can all easily understand. They perform a very simple job, which is to work between the pushrods and camshaft to help open the valves. However, these little buggers can have a serious impact on performance.

As you go through your engine build you will have many voices screaming in your ear. Whether it’s to go solid flat tappet—based on nostalgia—or to go hydraulic—based on street ability—or maybe even to blow your money on a fancy roller set. But what’s best for you and why?

Flat Tappet vs Roller

I’m not going to pull any smoke and mirrors nor pretend like this isn’t a topic that’s visited regularly. Out of the gate, I will say that roller cams and lifters are pretty much the best all-around choice. (So long as budget and event rules aren’t of concern.)

With that in mind, are they the choice for every engine builder? No. Why not? Well, because budgets can be tight, rules can be restrictive, and, of course, there are purists and traditionalists.

In the case that you plan to drag race, the class you are competing in may not allow you to run a roller camshaft. Something like Pure Stock classes will not allow a roller cam or really any cam that’s not within range of the factory-specs cam for the engine you are running. This is enforced to keep things fair in competition—so to compete, you’ll need to abide.

That being said, roller lifters will offer major power advantages, along with a smoother operating engine. One reason is that roller lifters have less friction on the camshaft, which makes it easier for the cam to spin. Additionally, lobe profiles can be much more aggressive. The cam can open and shut the valves much faster, which means they can keep the valve at full lift longer as well. This is because of the rollers on the bottom of the lifter—the smooth rolling surface makes it possible for the more aggressive lobe grinds to be used, as they won’t scrape or bind like the surface of a flat tappet lifter will.

But don’t take our word for it…

From SuperChevy: “The big advantage roller cams have over their flat-tappet cousins isn’t the reduced friction most people immediately think of, it’s increased tappet velocity (i.e., faster ramp rates). This increased velocity—as much as 30 percent—equates to more power. … The more aggressive ramp rate of roller cams typically requires higher spring loads to control the valvetrain motion.

Another major benefit to the roller cam is increased durability. The roller design is far less likely to fail compared to a flat tappet since they are not as reliant on oil splash to keep things functioning properly. Also, with flat tappet cams, dialing in the right spring pressure is far more critical compared to the more forgiving roller design. This reliability is why the OEMs shifted from flat tappet to roller cams in production vehicles. It’s also what makes a roller valvetrain the best choice for a hot rodded street engine.”

But it’s gonna cost ya…

The major drawback here is always thought to be price and installation. Where you can buy a flat tappet cam kit for something like $120, a roller cam kit will run you around $700. These are two low-ball prices, too—if you intend to buy from high-quality brands like COMP, you’re moving more towards $180 flat tappet and $1,000 roller. So, you pay for brand power.

As far as installation goes, you may have heard that roller cams can be a pain to install. “It is true that a roller cam and lifters cost more than a flat tappet cam and lifter set. But it isn’t necessarily true that you have to change much in your engine to run a roller cam,” explains HOT ROD. “Depending upon the specific grind you select, you may not have to add more than one or two parts to your engine.”

With that in mind, if you are capable of installing a flat tappet cam in an engine, you shouldn’t have much trouble installing a roller cam yourself. Valve springs are often changed (as per usual) and, if the engine is swapping from flat tappet, a camshaft retainer is often required. This is because the difference between the nature of cam grinds isn’t limited to just how aggressively these camshafts open valves.

On flat tappet camshafts, the lobes are sometimes pitched at a slight angle toward the rear of the block. This is done to help the lifter rotate during operation. It not only aids with lifter wear but also works to pull the cam into the engine as it rotates. Without this grind nature, the cam can tend to slide back and forth. Roller cams do not feature this design characteristic and will need a retainer to keep the cam in place.

Solid vs Hydraulic

There are a lot of debates on hydraulic vs solid lifters, but there are some key factors that come into play when running either lifter type in the performance world. Solid lifters are simple solid pieces of metal that ride on the cams surface and work to open the valves of the engine a little more. Hydraulic lifters are designed to do the same exact job, but they pump oil to the top of the valvetrain through the pushrods.

With hydraulic lifters, maintenance is low and you won’t have to spend much time worrying about preload outside of the initial installation. (Preload is the distance in which the pushrod sits down within the lifter. It is important in allowing the lifters to move.)

With solid lifters, valve lash will need to be set and adjusted from time to time. (Valve lash is the clearance between the rocker arm and the tip of the valvestem.) This is a crucial setting, as it will determine the performance and lifespan of the valvetrain and will keep valve duration and lift on key with the cam’s specs.

When to Use Hydraulic or Solid

Hydraulic lifters are traditionally thought to have a common weak point: the pumping design. This type of lifter collapses a little as the cam pushes up, and the resistance of the rocker arms keeps the pushrod in place. This creates a little bit of a buffer, which leaves them opening the valves just a little slower than the solid lifters will. On a street driven vehicle, the added protection of the valvetrain makes this sacrifice worthwhile. However, on high-revving track cars, this loss in response can be detrimental to real performance.

Though, it’s important to note that lifter technology isn’t what it used to be. “Hydraulic roller lifters are tall and heavy compared to flat tappet lifters, and also prone to pump-up,” says SuperChevy. “But, with the advances in hydraulic lifter design—namely short-travel lifters, tighter hydraulic piston clearances, and lightweight valvetrain components—many hydraulic lifter-equipped engines can easily handle 7,000 rpm or more.”

While SuperChevy is referring to roller lifters here, the same holds true at times for flat tappet cams. Though, if you do opt to run a hydraulic lifter on a high-revving engine, you should make sure that the camshaft can operate at the RPM you intend to reach out and touch.

With that in mind, if you intend to wind out into the wider RPMs, I’ll be the first to promote playing it safe and just going solid. Why? Well, it’s simply less parts to break. Solid lifters won’t pump up or collapse because they simply can’t. I’m not saying it’s the only way to go, but when the valvetrain is moving as fast as it will at 8,000 RPM, the margin for error becomes extremely small and the less factors that are involved, the safer one can feel.

When to Use Flat Tappet

While it’s pretty much accepted that roller cams will always be better, sometimes running flat tappet is still a good choice. Let’s not forget that for decades, flat tappet camshafts were the only option on the market and guys running them were easily able to crush the quarter mile, oval track, road courses, or any other type of race track on the planet.

So, are roller cams and lifters superior? Yes. But are they the only option for real performance? Absolutely not. They are a fantastic option, but so are flat tappet cams. Flat tappet cams are very straight-forward and, though a roller cam installation isn’t far off in terms of difficulty of installation, flat tappets are just a touch easier to install.

Let’s also not forget that they are much more abundant and you do have a better chance of finding the one you’re looking for locally. Maintenance of either is about the same, in terms of the process. But, if you do have issues with a roller cam and need to replace lifters, you’ll be spending a little more money. Basically, if flat tappet is what you can afford or if that’s just what you prefer, then rock it and go have a blast.

We’re sure you have an opinion on this–weigh in down below.