The Lives of Lifters, What You Need to Know
By John Carollo
It's like any other mechanical part in an engine. It has a simple yet specifically designed function, it's not overly complicated and it's definitely not the proverbial rocket science, tricked-out part. But there's more to know about the valve lifter than you may think.
First off, there are two distinct styles of lifters used in vehicles: hydraulic and mechanical. The mechanical versions are often called solid lifters as they do not have the hydraulic cushioning function. From there, how they meet the cam lobe surface determines the style, either flat tappet or roller.
The majority of lifters built are hydraulic flat tappet used in street vehicles. Flat tappet lifters have a crown face that meets the cam lobe while a roller is self-explanatory with a roller contacting the cam. Again, both styles can be mechanical or hydraulic.
In contrast, an overhead cam engine uses variations of the hydraulic lifter with followers and lash adjusters but no pushrods. The performance market prefers mechanical and mostly roller styles. OEM builders typically prefer the hydraulic versions because they require less service for the vehicle's owner and need virtually no adjustment yet they can be used with both flat tappets or rollers. The performance market prefers mechanical and mostly roller styles.
With continuing improvements in metallurgy and engine design, there was a noticeable shift from one style to another in the OEM ranks a decade ago, say engine parts experts. According to Federal-Mogul performance products manager, Barry Rabotnick, "In the '90s there was a large scale evolutionary move from flat tappet to hydraulic roller lifters. That's because the same principles that govern racing engine philosophy play out to street engines - if only somewhat. Friction equals horsepower and it also equals gas mileage."
The roller lifter move cost the industry big money but was deemed worthwhile and fewer and fewer hydraulic flat tappets were seen coming on street engines.
"Basically, the old small block Chevy flat lifter has been phased out in favor of the hydraulic roller and/or hydraulic lash adjuster," Gary Wertzbar of Clevite Engine Parts says. Chris Douglas of Comp Cams says this trend has a legitimate business advantage to it: "Hydraulic rollers are really big now. Obviously, they are a growing segment." In fact, he says his company uses what it has learned from its involvement in NASCAR racing for its street performance products.
Paul Plebanek of Topline-Hylift says his company expects this growth to continue. Specializing in aftermarket OEM replacement parts, Topline-Hylift is building a new 275,000 sq. ft. plant near Tampa, FL, primarily for hydraulic roller lifters, hydraulic cup buckets and directly related components.
Hydraulic roller lifters, according to our contacts, are suitable for pretty much anything including street performance vehicles. And that includes the benefit of being able to follow a more aggressive cam design. That explains their popularity in the truck and even boat market where they can be an easy "drop in" cam kit for owners and builders. The simple nature of these "retrofit kits" can offer an easy option to customers.
They are not without their limitations, however, as hydraulic lifters usually cannot handle too much in the way of higher rpms and performance. You must consider their extra weight for both the reciprocating weight of the lifter and its effect on the cam. This added weight actually ends up working against the hydraulic lifter in those situations, adding yet another weak spot to an already vulnerable valve train. Another factor to consider is functional geometry and how a lifter can or cannot be controlled. The OEMs want the most they can get from a lifter so they use them to run up to their service envelope and not beyond, as in high performance conditions.
The transition of a lifter from street design to racing includes many facets. John Steely of Howard's Cams told us about some of the differences. One of the biggies is internal hydraulic valving via the lifter's bleed rates. While the specifics are closely guarded secrets by manufacturers, the principal idea is that valving helps to be able to withstand the spring load rates, offer less preload and be of a beefier construction. For racing parts, less bleed is usually used.
Another difference can be seen in the method used to hold the lifter together. While the materials and the heat treats used are similar, on an OE version, it's not unusual to see a stamped steel ring used; for racing versions, a dedicated snap ring is used so the lifters can be taken apart more easily. "One more critical area is lash," Steely says. "OE lifters are set up with zero lash then turned one turn. Racing lifters use only a quarter-turn."
Lifter Troubleshooting And What To Look For
Logically, the wear surface is the first place to look to see just what wear a lifter has accumulated. Is the crown correct? Unless you can precisely match that crown with the proper hardness and no soft spots - which is unlikely - you could be creating a bigger problem by reusing lifters. Most builders and manufacturers strongly recommend using new components. Another factor here is the nature of today's more advanced materials and heat treating, which can give you a "false read" on the old parts. By far the best practice is to use all new contacting pieces when installing a new cam or rebuilding an engine. Bill Skok, president of Elgin Industries, says, "Engine builders really should be looking at using new lifters in all cases. We've seen too many shops end up costing themselves comparatively big dollars by trying to save a few pennies up front."
Watching out for lifter trouble is relatively simple. For flat tappet lifters - hydraulic or solid - the break-in period is absolutely critical. More aggressive cam designs and valve spring pressures may "amplify" the problems. True, with more pressure on the valves and cam grinds moving the lifter in a more dramatic gesture, the use of a good break-in lube becomes even more critical. Likewise for the contents of engine oils as additives have had to change to suit environmental requirements. Although break-in failures are easy to sidestep thanks to the vast array of extremely high quality break-in lubes available today some experts say the preventable failures actually seem to be increasing.
Another area that can be the site of trouble is the lifter bore in the block. As an example, Rabotnick describes some older engines that may have cycled around for their third, fourth and even fifth rebuild. The odds are that the lifter bores haven't received much attention and may now be out of round from excessive or premature wear. Much like a piston's bore, improper sizing in the lifter bore can contribute to a quicker and catastrophic failure.
Higher end race engines typically use bronze bearing sleeves in their lifter bores which can be checked often for any out-of-tolerance problems. When one is found, the sleeve can be easily replaced saving not only the valve train but the expensive block that has now become more of a parts holder. An engine builder's only option for a car owner who wants to keep his "numbers-correct" engine is to fix the problem correctly and maybe prevent future problems that would be bigger and more disastrous.
Another lifter problem is often revealed by the familiar sound of lifter clicking or ticking. It's called lash tick by most people in the business and can be caused by something as simple as a few small pieces of dirt in the lifter that collapse the hydraulic mechanism. Our experts say in 99 out of 100 times, the problem is caused by dirt that got in there, and unfortunately, that contamination can cause wear to the metal-to-metal contacts. This wear can also go into the body of the lifter, giving the needle bearings more room to dislodge from their cage.
According to Stephen Kutch from Jesel Valvetrain, if you're looking for problems in racing applications, "normally, it's the needles. Probably the weakest link of a solid lifter are the needle bearings themselves."
Other manufacturers agree, and, like Jesel, continuously addressing that problem in their extensive R&D departments. According to Comp's Douglas, the tallest needle bearing always carries the load. By sizing all of their needles right down to the microns, Douglas says the load is distributed more evenly so needle bearings will live a longer life.
In a more extreme engine valve train environment, lifter bounce can occur. Called "loft" or "launch," the lifter actually jumps off the cam. This not only increases the wear on the lifter's roller and supporting areas such as the roller's axle and bearings but often establishes a "divot" on the back side of the cam where the lifter comes back into contact much like an airplane's wheels upon landing. Sometimes the lifter will actually skid on the cam, too. The preferred method of operation for a lifter is to work smoothly in transmitting the motion. In racing applications, a simple over rev can create the perfect conditions for this to happen. Again, with the aggressive cam grinds and stronger valve springs, it's only a matter of time until the weaker component gives up after the abuse reaches the breaking point.
Street Vs. Racing Sales
Chris Douglas points out that there is more bundling of components for street performance than hard core racing sales. Bundling, perhaps best known in the fast food industry and their "combo meals," allows parts manufacturers and distributors to do the same with a cam kit.
Putting a package together complete with lifters, pushrods and even rockers provides one stop shopping for street performance customers. Douglas cites the popularity of "matched components for the street," but says racers are unique, usually preferring to pick and choose components, often preferring to buy their pieces separately.
To service both shopping styles, Douglas says his company's "Cam Help" service, where a bank of tech service people, mostly racers, manning a toll free phone line, has grown to be extremely popular: techs handle 2,500 - 3,000 calls a day.
Bill Skok of Elgin - which offers a full line of performance lifters under the Elgin PRO-STOCK® brand - says two key areas of opportunity are lifters for "claimer" engines and units precision-matched to an upgraded cam.
"Our strongest area of growth has been at more of the moderate-performance level, where engine builders and consumers are looking for exceptional quality and value in lifters and other parts. You'll find there are excellent options out there that might not be viewed by some as the ultimate in technology for a maximum-output engine but which are great parts that will handle almost anything you throw at them," Skok says. "Claimer engines are really driving our volume in a lot of performance components; it's not just lifters, but cams, rockers, pushrods and other performance parts that feature premium materials and designs. The bottom line is, there are excellent parts options out there for any performance motor and virtually any budget."
Skok says the same is true of matched cam and lifter kits for performance applications. "Take a close look at the quality that's available for most engines; you'll be surprised to find that it's not always necessary to go with the premium brands to get really good parts for most performance engines."
Leave It To A Racer To Go A Different Direction
The way Joe Shubeck (yes, that Gentleman Joe Shubeck, the famous drag racer who used to pilot the Hairy Hurst Olds, the first twin-engine four-wheel drive Funny Car back in the mid- 1960s) tells the story, he was under his drag car cleaning out the pieces of yet another blown up motor. He was particularly annoyed with having to find all the needle bearings that were formerly part of the lifters.
"There's gotta be a better way," he said back then, ultimately making the connection to rod bearings (stay with us, it will all make sense shortly). Rod bearings, Schubeck reasoned, ride on a layer of oil and last forever. Why couldn't the roller of a lifter ride on a layer of oil instead of all those darn needle bearings?
He says the answer for him was so simple, it eluded him for another 30 some years; mostly because he thought the concept was too simple to actually work.
Yet, that's the very simple premise Schubeck used to develop his Roller X lifters. Well, that, and the basic law of mechanical and hydraulic physics that says you can't compress a liquid. The next step was to figure out how to suspend a roller in oil during the compression of a lifter's duty cycle.
Doing so resulted in the first new design for a lifter in over 50 years, no small feat. The Roller X lifters have no axles and no needle bearings. In fact, the roller itself has no center hole, it's basically a finely sized piece of round stock trapped in the lifter body but suspended in oil for both the contact with the cam and how it "floats" in the lifter body. "Suspended in a film of engine oil just like connecting rod bearings float on oil while never touching the crank journal," explains Schubeck.
Although Schubeck made his name racing extreme drag raccing vehicles, he quit racing in the late '60s. At this time, the sport of drag racing was seeing frequent and violent clutch explosions. Flywheels and clutches were being overstressed, causing shrapnel that would rip through a car's body. Schubeck devoted his efforts to improving racing safety and developed the hydroformed Lakewood total containment bellhousing, which contained the shrapnel from the explosions.
Schubeck's Roller X lifters have half of the reciprocating weight of the typical lifter, but he says, more importantly, they offer improved safety to racers.
He says it works like this: needle bearings don't always rotate and start to develop flat spots (a graphic example of this would be a driveshaft's U-joints and their needle bearings. When replacing a U-joint, we always see just how bad those needle bearings can get). Once a number of needle bearings on a lifter get a dose of valve float, that, coupled with harmonics, start to forge flat spots on them. That creates overcompensated clearances that eventually allow the needle bearings to escape their cage and broken roller axles. Also, because of their round shape, these needle bearings make only a "knife edge" of contact with the surfaces they separate.
Schubeck's lifters get their oil the usual way of being pressure fed from the oil gallery and that, coupled with the oil splash off the lobes of the cam, keeps the oil on and more importantly, around the wheel as it moves on the cam. The oil forms a .001? - .002? cushion keeping the wheel from making direct metal-to-metal contact with its contoured seat inside the lifter.
Sales of his relatively new (2003) Roller X Lifters are, Joe says, "gaining momentum" in numerous aspects of motorsports. They can be used with virtually any rocker on the market, need no special oil (he says you can use "minimum nothing weight oil") and are available for Chevy, Ford, Mopar, VW and even Flathead engines. To use them, a key way slot will need to be machined halfway down the lifter bore (to keep the lifter from rotating) and a fixture is available.
When Schubeck finally got the idea to work, he says he was "madder than hell because I waited so long…the answer to that whole thing was staring me in the face."
Topline's Plebanek says his company has seen the engine market change dramatically since the early days. "We've been in it for a long time and we serviced the industry when there were only two Honda and two Toyota part numbers!"
Plebanek recalls that many of the early imports started without using lifters or overhead cam-style engines, simply opting instead for mechanical buckets or no lifters, just rockers.
"I've seen the market go from 70 percent overhead valve and 30 percent overhead cam to an even 50/50," he says, attributing part of that to the growth of high performance overhead valve engines in and out of OEM assembly lines.
"There's always going to be a demand for the old Chevy and Ford. But the volume is going to take off for the overhead cam, as far as OEM replacement."
Just what is the future of lifters? With the widespread use of overhead cam versions - complete with hydraulic lash adjusters - are OHV engines and simple lifters ready to fade from the scene? Not true, according to Bill Skok of Elgin, one of the world's largest manufacturers of pushrods. Skok points to General Motors as a prime example of a company that sees the value of OHV technology. "We've heard the speculation that pushrod lifters are going to go away. That's just not true. They are less expensive and more reliable for OEs to use."
In fact, there's already talk about the "Next Generation" of lifters coming out of Detroit. They will sport a lower profile to match up with an engine that sits lower in the chassis to present less upper engine mass to the car or truck's hood. And it's not just the engine's location, the engine itself is being made with less upper profile, mass and weight. The lower profile means the length of the lifter will be reduced, as will the pushrod length and upper parts of the block and heads. It's a challenging concept and entirely "do-able."
Stock and Performance Lifter Suppliers
Clevite Engine Parts
Crane Cams Inc.
Egge Machine Co.
Engine & Performance Whse
Engine Pro/Engine Parts Group
Howards Cams & Racing Components
Liberty Engine Parts
Melling Engine Parts
PBM Performance Products
S.B. International, Inc.
Schubeck Racing Engine Components
Schumanns Sales & Service Inc.
Scoggin-Dickey Parts Center
Sealed Power Engine Parts -
Speed Pro Engine Parts -
Sterling Automotive Parts