Camshaft technology is continually changing. From new lobe profiles to various forms of lobe placement, each manufacturer takes its own approach to modern performance. While flat-tappet grinds remain popular for reasons including overall cost and installation simplicity, retrofit roller technology for the Pontiac V-8 has lessened the modernity gap between it and its competition.
Such developments have forced similar changes in other valvetrain components. Today, we find low-mass valves, uniquely shaped valvesprings, and lightweight hardware in virtually any engine designed to extract maximum power at high rpm. But one component of that combination, which is as critical as any other, is the lifter. Follow along as we explore the different lifters available for Pontiac engines and learn the effects modern technology has had on them.
Hydraulic Lifter Basics
A typical hydraulic lifter in an overhead-valve engine includes a main body and an internal plunger-and-valve assembly that relies on engine oil pressure to continually adjust valve lash to maintain constant contact of all the valvetrain components during normal operation.
Camshaft technology is continually changing and new developments are typically aimed at im
While on the base circle of the camshaft lobe, pressurized oil from the lifter bore enters a feed hole and fills a cavity in the lifter body that's located beneath the plunger. As the lifter body follows the cam lobe and begins rising, valve-spring pressure transmitted through the pushrod compresses the plunger against its spring-loaded check ball, immediately isolating the lifter from the engine oil supply.
As the cam lobe travels toward peak lift, the lifter and plunger raise as a unit, lifting the pushrod, which in turn lifts the valve off its seat. Resistance from the valvespring pressurizes the oil within the lifter body, which causes a small amount to bleed outward between it and the plunger. This is referred to as "leakage" or "leakdown."
Once the lifter travels up and over the entire cam lobe and is back on the base circle, internal spring pressure causes the lifter to expand, forcing the plunger upward, which eliminates valve lash, opens the check valve, and allows pressurized oil to refill the lifter body cavity before the next lift cycle starts.
Hydraulic Lifters In Pontiacs
Pontiac's engineers incorporated hydraulic valve lifters into the development of its V-8 during the '50s, supplying each lifter bore with a relatively high volume of pressurized oil. Specific degrees of lifter-body-to-plunger clearance can be used to vary leakdown rate, and Pontiac employed various specific-rate hydraulic lifters for select street applications over the years.
The standard hydraulic lifter, like this well-used Pontiac unit, was developed decades ago
In most instances, plunger depth was preset using a tapered rocker arm stud and corresponding adjuster nut. The combination placed the plunger in such a position that the lifter would function correctly in myriad conditions and with normal valvetrain wear.
As engine speed increases beyond its intended operating range, valvetrain components can bounce or "float." Pressurized oil immediately takes up the excess lash during the refill cycle, causing the lifter to displace a greater-than-normal volume of oil. If this amount is greater than the lifter's leakdown rate, the lifter can "pump up," holding the valve off its seat, ultimately limiting engine rpm and power output.
Hydraulic "pump up" can be controlled with lifters that feature limited internal plunger travel and an adjustable valvetrain, which positions the plunger near the top of the lifter body during normal operation. This produces a semi-solid hydraulic lifter that operates conventionally, but extends maximum engine speed by several hundred rpm. Hobbyists can find similar results converting their Pontiac's standard non-adjustable valvetrain to a fully-adjustable setup and adjusting the plunger into the body 1/8 to 1/4 of a turn down from zero clearance.
Rhoads Lifters offers a complete product line of hydraulic variable-duration lifters. Its
Rhoads Variable-Duration Lifters
Many manufacturers have sought ways to improve the conventional flat-tappet hydraulic lifter and a few have developed units that vary camshaft valve events with rpm. Such pieces typically boost idle quality and low-speed performance, but it seems those offered by Rhoads Lifters are among the most popular. Here's what the company's Jack Rhoads has to say.
High Performance Pontiac: How long has Rhoads Lifters been producing its unique line of lifters?
Jack Rhoads: Our company began producing variable-duration hydraulic flat-tappet lifters over 30 years ago using a patented design developed by my father, James E. Rhoads.
HPP: How many different lifter sets does your company offer for Pontiacs and what is the cost?
JR: We presently offer two hydraulic flat-tappet variable-duration lifters for the Pontiac V-8. The first is our original Rhoads lifter (PN 9518), which retails for $110. The second is our newest V-Max design (PN 9518X) and starts at $149. The Super Lube option adds $30 to the cost of either
This exploded view of an original Rhoads lifter proves how simple a design it truly is. It
HPP: Can you explain the operational characteristics and benefits of each?
JR: Our original Rhoads lifter operates similarly to a standard hydraulic unit, using the same amount of oil flow, but our design leaks at a much higher rate. This reduces valve lift and duration at low and moderate engine speeds by as much as 0.020 inches and 10 to 15 degrees, respectively. That can increase idle vacuum by as much as 3 inches, improve idle quality and overall fuel economy, and increase low-end torque by as much as 15 percent.
Our V-Max design functions much like our original unit, but is fully adjustable instead and must be set much like a conventional solid. Lash preload can be set between 0.010 and 0.030 inches to reduce the camshaft's overall valve lift and duration, which at maximum leakage can increase idle vacuum by as much as 5 inches and improve low-end torque by 25 percent, when compared to a standard hydraulic unit.
As engine speed increases, there's less time per revolution for either version to leak down and both begin operating conventionally by about 3,500 rpm, restoring maximum valve lift and duration for peak performance. And because our lifters continually leak at high speed, they typically don't pump up as quickly as standard hydraulic units, making either design desirable for high-rpm use.
Rhoads Lifters' newest V-Max design is fully adjustable, allowing owner control over the a
HPP: Can you detail the Super Lube oiling option?
JR: It's a machined groove in the lifter body that runs its entire length and injects oil onto the contact surfaces of the camshaft lobe and lifter during normal operation to reduce friction and wear. Our testing indicates positive effects on component longevity without any subsequent effect on oil pressure.
HPP: For what types of hobbyist applications are Rhoads lifters popular?
JR: They seem most popular with owners who install a performance camshaft in a street engine, but want to maintain maximum idle quality and low-speed performance. However, they're commonly used in race applications because of their excellent high-rpm capability, too.
HPP: Is there any application for which you'd suggest they not be used?
JR: They seem to have little effect on engine operation when using a mild camshaft such as that found in a low-performance, passenger-car application. Either design would, however, be an excellent choice when running a factory high-performance grind like a Pontiac No. 041 or an aggressive aftermarket unit.
HPP: Can you explain the increased level of engine noise when running Rhoads lifters?
JR: The leakdown rate of our original Rhoads lifter is higher than that of a standard hydraulic unit, which makes it noisier at idle and low speed. It causes an audible "tick" like that associated with a traditional solid-lifter cam. Because our V-Max lifter leaks down at an even greater rate, additional noise is common, if adjusted to the maximum setting. The minimum setting is quieter than our original design.
A machined groove in the lifter's internal plunger allows pressurized oil to pass between
HPP: Is the "ticking" an indication of excessive valvetrain lash?
JR: By design, hydraulic lifters continually adjust to maintain zero valvetrain lash and ours are no different. Once the desired setting is found, there's rarely a need to readjust either design. The noise emitted when using Rhoads lifters is the result of the valve closing sooner when compared to a standard hydraulic. As engine speed increases, the accelerated closing rate dissipates until the point when the variable-duration lifter begins acting like a conventional unit and the noise subsides.
HPP: Does oil type or viscosity have an effect on operation?
JR: Like most companies that market camshaft-related components, we, too, suggest quality conventional or synthetic engine oil that protects against lobe and/or lifter failure. Running thick oil can affect the bleed rate of both lifter designs, and generally speaking, the higher the viscosity, the less leakage that occurs, which can lessen the overall effect our lifters have on an engine. But because so many variables are involved, we don't specifically suggest using any particular type or viscosity.
HPP: What are your suggestions when breaking in Rhoads lifters and a new camshaft, and when combining new lifters and a used camshaft?
JR: We simply suggest following the camshaft manufacturer's stated break-in and normal operating procedures when using a new cam and lifters. But there are countless instances where owners find the selected camshaft a little too wild for their taste and choose to tame it with a Rhoads. It's completely acceptable to install new lifters onto an existing camshaft and we tell owners to treat the situation like breaking in a new camshaft and suggest following the camshaft manufacturer's stated break-in procedure.
Rhoads Lifters' Super Lube and Crower Cams' Cam Saver options incorporate similar technolo
202 E. Main St.
San Manuel, AZ 85631
Crower Cams is a name synonymous with high-quality valvetrain components. In addition to its roller-lifter designs, the company also offers what many professional builders consider the best solid flat-tappet lifters on the market. We spoke with the company's David Crower to gain a better understanding of what makes its Pontiac offerings unique.
High Performance Pontiac: Does your company produce its own solid flat-tappet lifters?
David Crower: Ours start out as premium hydraulic units that we outsource and convert into solid units. They feature a high oil band to minimize leaks and maintain maximum oil pressure.
HPP: How many different solid flat-tappet lifters does your company presently offer for Pontiacs?
DC: We offer three. The first is our standard lifter (PN 66962-16), which retails for $145. The second is the standard lifter with our Cam Saver option (PN 66962X3-16), which retails for $170. And the third is our standard with the Cool Face option added (PN 66962X980-16), which starts at $220. All are available direct from Crower or through most major mail-order suppliers.
In addition to its Cam Saver option, Crower also offers its Cool Face option, which includ
HPP: Do your lifters require lifter-bore oiling restrictors or restricted pushrods?
DC: Our solid flat-tappets are designed to promote maximum-required oil flow to the top end to cool the valvetrain components and lubricate the valve guides. They are, however, internally restricted so there's no need for additional flow restrictors.
HPP: Can you specifically detail the Cam Saver and Cool Face options?
DC: The Cam Saver option incorporates a machined groove on the side of the lifter body that delivers about 25 percent more lubrication onto the camshaft lobe and lifter to combat excessive wear from high spring pressure. On a typical engine, that might provide as much as 15 ounces of additional oil flow per hour directly onto the components without affecting oil pressure.
Crower Cams solid flat-tappet lifters are among the best on the market. The company offers
As Electrical Discharge Machining (EDM) technology was introduced, we began exploring the effects of directing oil flow onto the camshaft lobe by way of the lifter face. We determined using our in-house spin fixtures that a 0.024-inch hole located 0.200-inch off the lifter's centerline significantly reduced lobe and lifter wear, especially when used on high-rpm engines equipped with high-ratio rocker arms and excessive spring pressure.
Our testing shows no adverse effects on overall engine oil pressure when using either type of lifter.
HPP: What do you see as the main benefits of a solid flat-tappet camshaft?
DC: The function of the hydraulic lifter can limit the effective rpm range of a given engine. Solid lifters give the option to run the engine higher, assuming that it's built to accommodate the extended power band.
Crower states that its solid flat-tappet lifters begin life as high-quality hydraulic unit
HPP: Do you have any comments/suggestions for those considering a solid flat-tappet camshaft?
DC: Along with the quality materials used to produce today's components, modern poly-locks have significantly reduced the need for continual adjustment, but any flat-tappet cam is susceptible to failure due to the lack of anti-wear additives in modern-spec oil and we suggest using our oil supplement to combat that. We also suggest that bracket racers regularly check lash settings to maintain maximum performance, while most hobbyists with street-driven engines can get away with checking them once or twice per year. Immediately search for any signs of wear if lash changes.
HPP: Do you see any immediate changes in solid flat-tappet lifter technology in general?
DC: Not when concerning lifter function, but we do offer a new line of solid flat-tappet lifters designed for extreme competition applications. The body is machined from billet steel, the Cool Face option is added, and the face is polished to a mirror-like finish. A typical cast-body lifter might pass the Rockwell hardness test in the 51 to 55 range. Our billet lifter tests between 64 and 66. It's the ultimate for those running extreme rpm and spring pressures, and requires a billet camshaft. Each set is made to order and starts around $450.
Crower Cams And Equipment
6180 Business Center Ct.
San Diego, CA 92154
Crane Cams has been producing valvetrain components for more than 50 years and, like its other lifters, the company's hydraulic rollers are some of the best on the market. The company's Product Manager, Chase Knight, explains the features of Crane's hydraulic roller lifters to us.
A machined hole passes pressurized engine oil upward into the lifter's hydraulic assembly.
High Performance Pontiac: Does your company produce its own hydraulic roller lifters?
Chase Knight: Our hydraulic roller lifters are produced in-house with long-term reliability as a primary goal. The lifter body is precision machined from billet steel that's heat-treated and ground to our stringent specifications. Its hydraulic internals are custom-fit in the body to ensure proper leakdown rate and quiet operation. A special wheel, bearing, and axle assembly is then installed.
HPP: How many different hydraulic roller lifter sets does your company presently offer for Pontiac engines?
CK: Just one. Our No. 28532-16 retrofit hydraulic roller lifter is specifically designed for the Pontiac V-8, so it isn't the same as other 0.842-inch diameter roller units we offer. The set carries a retail price of $635 and is available direct or through most major mail-order suppliers.
HPP: Have you found an rpm range where pump-up occurs?
CK: The maximum engine speed of a hydraulic roller combination is dependent on the camshaft profile, valvespring pressure, and overall weight of the valvetrain components. In most instances, 6,500 to 7,000 rpm is achievable in a correctly prepared street engine. Extreme racing applications have turned over 8,000 rpm successfully, but we're talking about all-out race-prepared engines with very stiff valvesprings and lightweight components.
These beefy hydraulic roller lifters from Crane Cams are produced using a unique manufactu
HPP: Does lifter weight have any bearing on maximum rpm?
CK: The weight of the lifter and pushrod is of much less consequence. It's the weight of the valves, valvesprings, retainers and locks, and the overall multiplication effect of the rocker arm ratio that tend to limit maximum engine rpm. The heavy valvetrain components and stiff valvesprings cause hydraulic lifters to leak more quickly, which can limit maximum engine speed along with the less aggressive profile of a hydraulic roller grind.
HPP: Do your hydraulic roller lifters have direct-axle oiling?
CK: Our hydraulic roller lifters don't use direct-axle oiling, primarily to prevent the loss of internal oil pressure, which could have a negative effect on the lifter's hydraulic function. Instead, we use a dynamic system we refer to as "focused oiling." Since some oil is left behind during each lift cycle, this residual oil on the camshaft lobe and lifter roller wheel is directed to the lifter's needle bearings through channels machined into its body. Both ends of the needle bearings receive a supply of oil for lubrication and to carry away frictional heat without any loss of oil pressure.
HPP: Is continual preload adjustment of any concern?
CK: We recommend that 1-1/4 turns of preload be used to minimize oil volume in our hydraulic roller lifters. Once proper preload is set, there should be no need for future adjustments unless something drastic happens, such as over-revving, which can compromise other components in the valvetrain.
HPP: What types of hobbyist applications do you see hydraulic roller camshafts used most in?
CK: Retrofit hydraulic roller camshafts and lifters are being used in a broad range of applications, from street machines and musclecars to dedicated drag racers. The benefits associated with roller profiles typically include wide torque and power ranges and, when combined with the low-maintenance design of a hydraulic lifter, they seem to provide superior results when compared to a conventional flat-tappet cam and lifter setup. They're also unaffected by modern oil quality concerns.
HPP: Is there any application for which you'd suggest not using a hydraulic roller cam?
CK: We feel it may be more advantageous to use a solid roller cam and lifters in applications that will encounter engine speeds in excess of 7,000 rpm over long periods of time. As mentioned earlier, a hydraulic roller will certainly reach those figures, but the expense of the premium valvetrain components required may not be reasonable for the usage intended.
HPP: Do you see any advantage in combining solid roller lifters with a hydraulic roller camshaft?
CK: This is something we simply don't suggest. It seems some feel that they're saving money by installing less-expensive solid roller lifters on a hydraulic roller cam, but it could cost them in the long run. The lobe profiles of a hydraulic roller camshaft don't incorporate the clearance ramps necessary for the proper operation of solid lifters, and severe valvetrain damage and shortened reliability are very possible. Just the same, we don't advocate combining hydraulic roller lifters and a solid roller camshaft.
530 Fentress Blvd.
Daytona Beach, FL 32114
Comp Cams solid roller lifters are the choice of many builders. These high-quality units o
Comp Cams remains on the technology forefront and is often considered an industry leader. The company's Research and Development Engineer and Cam Designer, Billy Godbold, explains the features of its solid roller lifters.
High Performance Pontiac: Does Comp Cams produce its own solid roller lifters for Pontiac engines?
Billy Godbold: Comp Cams designs all its lifters from a clean sheet of paper and our solid roller units are no exception-they're processed from bars of steel.
A tiny hole machined into the lifter body applies pressurized oiling directly onto the rol
HPP: How many different solid roller lifters does your company presently offer for the Pontiac V-8?
BG: While some lifters may fit multiple applications, we won't force a lifter into an application just because it fits in the same hole. We offer one specifically for Pontiac-No. 859-16. It retails for around $450 per set and is available direct, or through most mail-order suppliers.
HPP: Do Comp Cams solid roller lifters require lifter-bore oiling restrictors or restricted pushrods?
BG: No, they're internally restricted and contain a 0.016-inch hole that's Electrical Discharge Machined (EDM) into the body to feed the needle bearings of the roller wheel's axle.
HPP: Can you detail the positive axle-oiling feature?
BG: Oil flow toward the wheel is in the range of 5 to 15 percent of total flow through the lifter. Our in-house testing with and without holes shows no measurable effect on overall oil pressure using a standard-style gauge.
HPP: Does that testing show extended lifter life?
BG: We have a tremendous number of bracket racers running season after season on our older (non-oiling) lifters without any issues, including engine speeds in excess of 8,000 rpm, open-load spring pressures of 900 pounds, and high-ratio rocker arms that result in 0.800-inch valve lift. You'd ultimately assume that a majority of our solid roller lifter warranty issues would come from this venue of the hobby, but we found most came from vehicles driven primarily on the street.
In street applications, the ratios are typically lower and the spring loads and operating rpm are dramatically lower, so the components should theoretically live longer. Oil thrown from the crankshaft and connecting rods at high rpm lubricates the roller portion of the lifter in race engines, but the lack of lubrication in low-rpm street engines limits life expectancy. So we changed the axle material to a special tool-steel alloy and incorporated direct-oiling provisions.
Because Comp Cams rebuilds its lifters for customers, we've been able to see how much of a real-world effect positive axle oiling has had on solid roller lifters. There's been dramatic improvement across the board. The end result is a vehicle that can be driven on the street without the owner feeling as if the solid roller lifters are living on borrowed time. And while our older (non-oiling) lifters would last for years when used in race applications, racers seem just as happy with the upgrade.
HPP: What advantages do you feel solid roller camshafts typically contain?
BG: Roller cams of any type give a tremendous advantage to performance because of how fast you can move the valve into the region where heads typically flow best. With an 0.842-inch flat-tappet lifter, like that of a Pontiac V-8, the tappet moves about 0.007 inch per cam degree without running off the edge, while a roller can move the tappet 0.009 inch per cam degree or faster. This gets the valve off the seat and to max lift quicker, providing more area and lift under the curve.
HPP: Is continual adjustment a concern?
BG: It certainly was some years back, but poly-lock adjustment nuts are much better today. We suggest checking lash with the first oil change, and if it didn't move, check it with every other oil change unless you notice increased valvetrain noise at idle.
HPP: Do you see any advantage in combining solid roller lifters with a hydraulic roller camshaft?
BG: The initial acceleration rate of a hydraulic roller camshaft lobe is typically more aggressive than that of a comparable solid roller grind. The hydraulic unit tends to get the valve off the seat quicker and into the meat of the lift where the cylinder head flows best, but, unlike a solid roller grind, the profile of the hydraulic roller lobe tends to limit maximum engine rpm.
This diagram from the Pontiac Service Manual provides the names of all the components foun
A solid roller lifter can be used with a hydraulic roller camshaft and a lash setting of about 0.006 inch, cold. The main advantage of the combination includes extending the engine's maximum operating rpm by a few hundred from improved valvetrain stability and the fact that the lifter doesn't leak down.
We've also seen instances where customers have successfully installed hydraulic roller lifters on a "tight-lash" solid roller camshaft. We consider a tight-lash solid grind as one that requires less than about 0.020 inch cold lash, and since a hydraulic is designed to run between 0.004 and 0.010 inch, the lifter can take up the lash, operating quietly while maintaining strong high-rpm capability. We do, however, suggest contacting the camshaft and lifter manufacturer(s) to ensure that either combination is compatible.
HPP: Do you see any immediate changes in solid roller lifter technology in general?
BG: Not in the immediate future, but the material, heat-treatment, and coatings industry is changing so rapidly that we can't look forward without seeing opportunities for improvement. The technologies we use today were simply unavailable 10 years ago and I feel that will be the case again 10 years from now.
3406 Democrat Rd.
Memphis, TN 38118
For this story, we asked that each company highlight a specific type of lifter in its product line to avoid repetition and to explain the advantages of the various designs of lifters. Please keep in mind most of these same companies, as well as others that were not interviewed, do produce solid and hydraulic flat-tappet lifters, and solid and hydraulic roller lifters
We didn't explore all offerings from all companies, as it wouldn't be practical. However, the presented information should provide a better understanding of the types of lifters presently on the market, how modern technology has affected each, and aid for hobbyists when making camshaft-related decisions.