is a roller cam worth the extra cost vs a flat tappet design



is a roller cam worth the extra cost vs a flat tappet design

Postby grumpyvette » October 30th, 2010, 8:19 pm

heres some info from COMP CAMS
" Flat Tappet vs. Roller Tappet Lifters
theres far more than just the cam and lifters required to swap types of cams, if your engines currently equipped with a flat tappet cam your almost sure to need a new
timing chain set
cam button
new push rods
obviously a new cam and roller lifters.
and its almost always in your best interest to add better valves springs, retainers,keeper rockers etc.
its also very common to need spring pockets cut, new spring shims etc.

a flat tappet hydraulic cam will function correctly if properly installed but compared to a decent roller cam it can easily cost you 30-40 plus hp in some applications
good hydraulic flat tappet cams and lifters are significantly less expensive at $170-$600 for name brand components vs $870-$1500 for a roller set up,obviously depending on components selected and changes required.

CAST CAM CORES ARE NOT DESIGNED TO HANDLE OVER ABOUT 130lbs SEAT and 400lbs OPEN SPRING LOADS YOU NEED A BILLET CAM CORE FOR DURABILITY IF THOSE LIMITS ARE EXCEEDED
Isky claims that the Comp XE cams violate the 47.5% rule. The 47.5% rule applies to flat tappet cams for SBCs with 1.5 rockers but the concept is still the same for other configurations where the designs are "on the edge" or "over the edge" for lobe intensity. For 1.5 ratio SBCs, the duration at .050 must exceed 47.5% of the total valve lift or your asking valve train problems. For example, take a Comp Cams Magnum 280H, with 230 duration and, 480 lift...230/.480 = 47.9% which exceeds 47.5% therefore would not pose a threat to components. We do not regularly hear about the older, safer HE and Magnum designs rounding off lobes anywhere near as often as the XE cam designs. Unfortunately, some of the Comp Cams XE dual pattern lobes break this 47.5% rule on the intake side so they are likely to be problematic. The design has "steeper" ramps that are too quick for durability and reliability according to other cam manufacturers. They will wipe lobes in a heart beat especially if you have not followed the proper break-in procedure. Other designs are more forgiving during break-in and less likely to fail.
In nearly all circumstances, a good roller camshaft design will outperform its flat tappet counterpart. Among the benefits of roller cams are higher tappet velocity, more lift and more area, along with reduced valve train friction (often a 15+ hp increase) and higher engine rpm with little effect on low speed driveability and power.

Roller tappets are also reusable, which makes it possible to swap just the camshaft without the expense of new lifters. And finally, roller tappets are far less prone to wear, allowing higher spring loads, and they are more consistent with today’s oils.

The biggest advantage to building an engine with a flat tappet cam and lifters is the lower up-front cost. It can be significantly less expensive to use a flat tappet setup but should you decide to install a new camshaft, flat tappets are not reusable, roller lifters are more expensive. You will need new lifters as well.[/color]"

the answer depends on your goals, a good flat tappet cam and lifters usually costs $400-to under $240 some times under $159,
keep in mind the main reason solid lifter roller cams tend to have reputation for durability issues is the much higher valve spring pressures and stress levels used to allow solid roller cams to operate at high rpms, once you exceed about 6000 rpm valve train stress loads increase rapidly

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MouseFink wrote:The Cadillac CTS-V lifters, GM-88958689 (box of 16 - $296.36 msrp) will not withstand bone crusing valve spring spressure for long. The Cadillac CTS-V lifters are lighter weight and are no stronger than standard Chevrolet LS-7 lifters, [b][color=#0000FF]GM-12499225 (box of 16 - $139.76 msrp)[/color][/b] or GM-17122490 (box of 8), AC Delco HL-224 hydraulic roller lifters. If you use standard or aftermarket SS valves and valve train components with more than 130 - 150 lb. seat pressure and 330 -360 lb. open pressure, you are better off using hydraulic roller lifters that can withstand that much pressure, such as Comp Cams 875 Reduced Travel or Comp Cams 15850 Short Travel hydraulic roller lifters with restricted oiling.

The Chevrolet LS and Cadillac CTS-V lifters are designed to be used with less than 100 lb. seat pressure and 300 lb. open pressure. That is because instead of bone crushing valve spring pressure, the Chevrolet LS and Cadillac CTS-V engines use titanium locks and retainers with sodium filled and titanium valves. Those lifters also have restricted oiling for moderate load beehive valve springs. Those type valve springs have progressive pressure and do not need to be flooded with oil for cooling. The Chevrolet Z06 and Cadillac CTS-V engines are supercharged and don't need to be be spun up to the stratosphere to make over 500 HP.BTW...You don't have to specify "LS7 lifters" anymore. You can just call them "Chevrolet roller lifters" because GM uses the GM-12499225 (AC Delco HL-124) roller lifters as service replacements in all 1991-2013 V8 engines, except the Cadillac CTS-VR engines.

example
http://www.summitracing.com/parts/LUN-60104LK/

http://www.summitracing.com/parts/CRN-110692/

http://www.jesel.com/valvetrain/index.p ... rs/tie-bar

for name brand parts, off brands can be even cheaper

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http://www.hotrod.com/techarticles/engi ... z2FeQk91VU

viewtopic.php?f=52&t=8582

viewtopic.php?f=55&t=58&p=36446#p36446

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factory blocks with sheet steel lifter retention springs are NOT designed to exceed about .550 lift or 6000rpm
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STOCK dog bone design hydraulic enclosed wheel roller lifters are generally designed for less than .550 lift and less than 6000rpm
the stock Chevy hydraulic roller lifters , dog bone and spider springs don,t always work reliably, ALL THE TIME with engines having over .500 lift or when spun over 6000rpm, its not all that rare for the lifter ,retainer to bend the retainer spring allowing the lifter to spin sideways, in the lifter bore, resulting in a destroyed cam, thats why Ive suggested BRAND NAME ,AFTERMARKET RETRO FIT CAM COMPONENTS BE USED
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roller blocks have taller lifter bores, because roller lifters are taller, and a provision to bolt the lifter retainer spring, but they can be very easily used for the earlier flat tappet lifters if desired by simply removing the spider(SPRING RETAINER), keep in mind most roller blocks use one piece rear seals
example

http://www.summitracing.com/parts/SUM-K1106/

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notice the more aggressive cam lobe acceleration rate on the roller cam lobes
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notice the stepped cam nose to fit retainer plate

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a good hydraulic roller cam and lifters costs a good deal more
example

http://www.summitracing.com/parts/ISK-201282294/ cam $280

http://www.summitracing.com/parts/HRS-91164N/ lifters $297


or more


http://www.summitracing.com/parts/LUN-60113/ cam $320

viewtopic.php?f=55&t=58&p=36446#p36446

http://www.summitracing.com/parts/CCA-885-16/ lifters $499

http://www.summitracing.com/parts/CRN-11532-16/ lifters $635

viewtopic.php?f=52&t=282&p=345#p345


having a REV-KIT that retains the lifters in their bores, to maintain oil pressure, even if the rocker comes loose or push rods breaks is a good idea
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Tech Tip - 2008

Roller Lifters: Keep 'Em Rolling Longer

Most racers are aware of the advantages of Roller Lifters. For those who are not, a brief review is in order. Roller Cams & Lifters are employed today in all-out racing engines where valve lift/area requirements preclude the possibility of employing a flat tappet (solid lifter cam). Higher Lift requires higher valve spring loads (pressures) and flat tappet cams can only handle so much. Additionally, increased rates of lift (cam lobe velocity) above .007" per degree for example on an .842" diameter G.M. lifter, would cause the lobe to reach-out over the edge of the lifters' cam face. Consequently, with either too much spring or too high a lift rate, most racers know that extremely radical flat tappet cams will eventually self-destruct.

But, what about Roller Lifters? Are they as indestructible as many believe? How do we prolong the life of their roller bearings in today's modern race only engines? Roller lifters require special care and maintenance if they are to provide good service life. Here are the 4 most important factors you should consider to insure their success.

1. AVOID DRY "START UP": Roller Lifter Bearings are assembled with a "tacky" rust-preventing grease that is not intended for lubrication. Therefore, new lifters should have their roller bearings thoroughly washed in clean solvent or acetone to completely remove this assembly grease. After air drying, premium motor-oil (non-synthetic) such as Penzoil SAE 25W50 GTP Racing Oil (The best of the mineral based oils) or Amzoil "Red" Racing Oil (synthetic) should be used to pre-lube the bearings just before installation.

2. AVOID "OVERLOAD": Increased load always means reduced service life. Want 50% more thrust from a jet engine? Ask Rolls Royce or G.E. and they'll tell you to expect about ¼th the service life between overhauls. Similarly, employing drag race valve springs in the 900, 1000 to 1100 lb. Range will reduce the life of your roller bearings between rebuilds much the same as will employing high-impact roller cam profiles.

3. EMPLOY A REV KIT WHEN POSSIBLE: The primary advantage of Camfather Ed Isky's invention of the 1950's is that by pre-loading each Roller Lifter Bearing to its respective cam lobe, you eliminate needle roller bearing "skew". Skewing (the momentary mis-alignment of the bearings' needle rollers to their respective races) is provoked by the start-stop skidding action of the roller bearings each time the lash is taken-up. Eliminate it and you extend roller bearing life dramatically! Unfortunately, many engines such as the Big Block Chevy which could use one the most, don't lend themselves to such an installation because of the severe angularity of the pushrod coming out of the lifter.

4. EMPLOY LIFTERS WITH "PRESSURE-FED" OIL TO THE NEEDLE ROLLER BEARINGS: Hope is a good thing. But hoping oil will eventually find its way to your Roller Lifter bearings is not. Unfortunately, most roller lifters on the market do not pressure feed oil to the needle rollers, depending on the "splash & a little luck" system instead. In contrast, all Isky Roller Lifters feature pressure fed oil to their roller bearings. Isky's Top of the line "Red Zone" Series lifters feature an exclusive 3-Point "Multi-Port" oiling system to constantly bathe the needle rollers with cooling lubrication. Additionally, they feature our famous Marathon Roller bearing with the toughest shock absorbing heavy duty outer bearing race on the market for the highest possible load carrying capability and sustained Hi-Rpm Endurance. And, they're fully rebuildable, making them your best long-term value!

back to top
read thru this info, in the links below
http://www.idavette.net/hib/camcon.htm

http://www.chevyhiperformance.com/techa ... index.html

http://www.badasscars.com/index.cfm/pag ... prd100.htm

http://www.thirdgen.org/sbc-camshafts-primer

http://www.moparmusclemagazine.com/part ... index.html

viewtopic.php?f=70&t=1701&p=4159#p4159

http://www.chevyhiperformance.com/tech/ ... index.html

http://www.stockcarracing.com/techartic ... index.html



you should also keep in mind that a roller cam valve train with the same lift and duration as a flat tappet cam, can provide a good deal more port flow potential and resulting power, , how much more power is mostly the result of how much more port flow and volumetric efficiency you can get from the engine combo that the flat tappet cam will not be able top access because the valve opens longer per degree of rotation on the roller cam lobe and the lift and duration,the valve sees increases, roller cams have a far lower percentage of lobe wear and less friction, both tend to result in more usable horsepower.
now if your current flat tappet cam is providing most of the engines potential then the roller cam will only provide a mild improvement, but in most cases you can expect a 15hp-40 hp gain, (depending on displacement, port flow,exhaust scavenging etc,)over a similar flat tappet design with similar duration at .050 lift, but in many case the roller cams peak lift will be noticeably more.
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within certain limits ,the larger the lifter diameter the faster the cam lobe acceleration ramp can be, chevy has a lifter diam. .842
ford uses a .874 diam, Chrysler .904 diam.
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but if your willing to pay for special cams and insert solid flat tappet lifters from the cam tunnel side you can use mushroom base race lifters in a chevy
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the slight bevel on the cam lobe and the slight convex surface on the lifter base in combination with the lobe center-line being slightly offset from the blocks lifter bore results in the lifter rotating in its bores as the lobe rotates under the lifter base
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but even roller cams can wipe out lobes if the valve train components or valve train lubrication,and geometry is not set up correctly
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Comparing Cam Lobes – The roller camshaft (on the left) has steeper opening and closing ramps which allows for more time at max lift.

example
heres two similar hydraulic performance cams

heres a flat tappet with 246 duration and .500 lift
http://www.cranecams.com/product/cart.p ... il&p=23763
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heres a hydraulic roller with the same 246 intake duration with a .558 lift
http://www.cranecams.com/product/cart.p ... il&p=24185


BTW if your thinking about getting those stamped steel, roller tip rockers , DON,T!!, they have a tendency to fail, and they don,t handle high spring pressures well, and they don,t reduce friction much so they are basically a (FEEL AND LOOK GOOD" part that doesn,t do much constructively[/color]
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Because, easily 90% PLUS of the friction in the valve train is NOT on the contact between rocker arm tip and the valve stem, so swapping to a roller tip on a rocker provides negligible benefits in friction reduction.
you can buy decent quality full roller rockers, for well under $250-$300
and roller tip rockers commonly cost 1/2 or more of that making the full rollers a much better option
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: is a roller cam worth the extra cost vs a flat tappet design

Postby kelley555 » November 1st, 2010, 11:15 pm

In the old days it was normal to run a 11:1 c.r. for a street car.The pump gas back then would support that c.r. They used the regular lobe cams with,not so steep ramps,that bled off cylinder psi.Today,you see lower compression engine making big horsepower with hydraulic roller cams.They kinda fake or make similar cylinder psi as the higher c.r. because the ramps on the hyd. roller are steep/fast. A regular hydraulic or mechanical cam only wishes it could run on those steep ramps. All the manufacturer's went to the hydraulic roller engine's,why,cause they ran more friction free/better mpg & made a ton of power at a lower compression ratio using our junky gas's of today.Certainly the hyd. roller setups cost wasn't the reason,they're more expensive.If one wants to make power on pump gas & in a lower c.r.engine,then a hyd.roller cam engine is the way to go.So,you get what you pay for when you try to cut expense's from the regular cam to the hyd. roller cam.That's were most old school guys get in trouble & get lured away from the close tolerance higher billet retro lifters.Even the Edelbrock Performer Rpm Series Billet lifter(1500-6500rpm) look like a Morel to me.Who wants to spend a lot on a engine,then cut a $150-$200 corner.Edel. are great lifters,a little heavier than the Crane billet ,but not even a comparison to the one's made cheaper imported. Cold cast technology Retro Hyd.Lifter,sounds like a cast lifter to me.I guess if one would use cast pistons in their engine,they'd probably match it with the hydr.cast roller lifter's anyways.As Grumpy would says,if you control the valve train with good billet hyd. roller lifter's & sufficient valve spring psi,there's a good chance you won't see the DREADFUL "valves tapping a piston".Later Jr
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Re: is a roller cam worth the extra cost vs a flat tappet de

Postby grumpyvette » April 27th, 2011, 2:42 pm

Moving Up to a Hydraulic Roller Cam


One of the quickest ways to gain a significant performance boost is to move up to a hydraulic roller camshaft. This conversion gives you a lot of advantages over a standard hydraulic cam.


The advantages of a roller cam include: no need to break-in the cam on initial startup, the lifters can be reused if you change cams, the open and close ramps of the lobes are faster, giving you more torque and horsepower for any given grind, roller cams wear at a fraction of the rate of standard cams, and roller cams can use the latest blends of motor oil with out the zinc, so no additives are needed.

A few things are different about a roller cam installation. A standard cam is ground in a way that causes the lifters to rotate during operation to minimize wear. This design causes the cam stay in place by itself as the engine turns. The roller cam design does not need to rotate the lifters, so it will “float” in place during operation.

To keep the roller cam from moving too much, you need to use a cam button between the cam cover and the cam gear to hold it in place, and a Torrington bearing behind the cam gear to keep the cam gear from damaging the block. You will need to set a camshaft end play by using shim washers (similar to setting crankshaft end play). Lastly, you need to make sure that your distributor drive gear on the cam, and the drive gear on your distributor are compatible.

Roller cams are hardened steel, and if mated to a soft iron distributor gear, it would wear out the distributor gear quickly. Most cam makers press on a soft iron gear on the camshaft at the factory, so in many cases you need to do nothing. However, if your roller cam has a hardened gear, the cam manufacturer usually sells a matching hardened steel distributor gear for you to use.

If you are retrofitting an older engine that did not use a roller cam from the factory, you will need to use a retro fit roller cam and retro fit roller cam lifters. These parts have the correct geometry to go into an older engine and have their own unique part numbers. Also, you will need to use shorter pushrods for a roller cam, and the manufacturer will have the correct length ready for you. If your engine is newer and has a roller cam from the factory, you will use a roller cam and lifters that are designed as direct replacements. Roller cams will work with any rocker arm design.

Going to a roller cam upgrade is one of those few times where you can really tell the difference it makes when you drive. Roller cams are more expensive, but if you can convince your customer to come up with a few extra bucks, it will really be worth the investment.

– Tech Tip courtesy of Summit Racing

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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: is a roller cam worth the extra cost vs a flat tappet de

Postby grumpyvette » November 14th, 2011, 9:16 am

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these two above make good cruising cams in a 9.5:1-10:1 cpr 383 and all require converter and rear gear changes to maximize the results

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these two above make good performance upgrades in cars used for daily transportation if your willing to put up with a lope in the idle and some loss of low rpm torque in exchange for more power higher up in the rpm band cams in a 10:1-10.5:1 cpr 383 and all require converter and rear gear changes to work correctly

all these cams below make good performance upgrades in cars used mostly for weekend toys with less and less compatibility for use in daily transportation if your willing to put up with a lope in the idle and some significant loss of low rpm torque in exchange for much more power higher up in the rpm band cams in a 10.5:1-12:1 cpr 383 and all require converter and rear gear changes to work correctly or even function in most cases
READ THIS
viewtopic.php?f=52&t=3810&p=10200&hilit=+small+base+cams#p10200

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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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