running a cast core roller cam on the street with more than MINIMAL spring pressures for the intended application IS JUST asking for valve train problems, heres a comp cams grind on a cast core failure,(BELOW) now ANY brand ,of roller cam can fail....but IVE had few (NONE) problems with CRANE,CROWER,ISKY ROLLER CAM components, when matched components were used,you'll generally want to keep peak valve spring loads under about 400lbs on a cast core cam and that's what I usually use, (PERHAPS IVE JUST BEEN LUCKY?, or its that I generally build stroker engine combos designed to run under 6500-6700rpm

CROWER AND ISKY sell decent lifters,

ERSON SELLS MOREL LIFTERS
http://www.pbmperformance.com/store.php?catId=420

Ive used them without problems, ERSON sells them, in fact the last couple engines I built Ive used the ERSON lifters MADE BY MOREL,but keep in mind the cam lobe design and spring load rates have a great deal to do with the lifter life span along with the oil flow rates. the more aggressive the lobe design and the higher the spring loads the lower the lifter and cams expected life span will be, especially if you get up into valve control issue inducing rpm ranges



high spring loads don,t play well with roller cams over long term use, heres a very clear example of why you should only use Billet cam cores with roller cams having over about 320 lbs of spring pressure and why you MUST verify valve train geometry and clearances.










I think you'll find the CRANE/ISKY/CROWER parts significantly better made. you may also want to do what I do on most blocks...


http://store.summitracing.com/partdetail.asp?autofilter=1&part=CCA%2D5003&N=700+4294925139+400114+1005+115&autoview=sku

use this tool to significantly increase the oil flow on the cam lobes (look on page 334)
http://www.compcams.com/technical/Catalogs/106-07/330-343.pdf

viewtopic.php?f=52&t=282&hilit=lube%E2%80%A6

isky vs comp roller lifters, notice the much smaller comp cams axle size, and how much wider the oil band is, on the comp the lifter oil band ,
theres advantages and dis-advantages to each design, small differences can make a big difference in durability

bits of flat tappet cam break-in info
http://www.compcams.com/Community/Artic ... 1578676008

The following Mechanical operating clearances must always be verified to ensure proper operation of the camshaft:
Spring coil bind clearance
Retainer to seal/valve guide boss clearance
Piston to valve clearance
Rocker arm slot to stud clearance
Camshaft end play
Distributor shaft and gear end play
Connecting rod to cam clearance
Proper hydraulic lifter pre-load or lash clearance
Proper valve train geometry
proper spring load rates
rocker to retainer clearance
a decent BILLET cam core, proper valve train geometry, moderate spring pressures and quality roller lifters will prevent a great deal of cam lobe wear issues

these are both cast core cams (look between the lobes) the dark surface is a flat tappet cam lobe coating, the polished is a roller cam


its been my experience that many cam failures are related to clearance issues or lack of correct lubrication far more than the use of the less than ideal spring load rates.
you might be amazed at the number of guys I see who install valve springs, even shim them to the correct height but never check the retainer to guide clearance,valve seals or valve train geometry, or bother to verify the oil flow thru the valve train, on all 16 rockers
and adding a few of the correct magnets traps almost all the metallic crud from worn lifters and lobes BEFORE it gets into the oil pump
keep in mind that some roller lifter cam lobes tend to have rather aggressive ramps to open the valves faster and hold them open longer


LINKS YOU NEED TO READ THRU
viewtopic.php?f=52&t=282

viewtopic.php?f=52&t=181

viewtopic.php?f=52&t=2166&p=5840#p5840

ISKY CAMS TECH TIPS

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!

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Don't be afraid of doing a retro fit roller conversion to your existing block. The aftermarket lifters are a couple hundred dollars more than the factory roller lifters, but are lighter than oem rollers, and are designed for higher rpms and spring load rates and in most cases lubricate the rollers more efficiently. If you plan to twist some rpm, the retro roller setup may suit you better. And, you save the expense of buying a newer block, and oil pan.

that's valid info, and Id also point out that the SBC O.E.M hydraulic roller ,spider , dog bone,springs and lifter arrangement needs clearance work, and won,t have the proper spring load rates for rpms over about 5900rpm, in most cases , or lifts after about .500 in most cases, and does not work all that well once valve lift exceeds about .550, while the aftermarket lifter designed tend to be more stable.
PLUS the fact that ALMOST ALL un-modified factory sbc heads stop flowing well at about .530 lift
KEEP in mind that both the stock cylinder heads(even modified) and standard production block are usually a restriction to your potential power and durability once your looking to exceed about 450-500hp, yes we all know guys who successfully push past those limits but stress is cumulative and its only a mater of time!

http://www.lunatipower.com/Product.aspx?id=2532&gid=310


currently the high rpm lunati hydraulic roller lifters have about the best reputation for durability , but they are expensive
http://forum.grumpysperformance.com/viewtopic.php?f=52&t=181

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=796

the use of factory hydraulic roller lifters is a great idea on a street combo to save money, but once you get more serious its a known restriction to your engines power potential