FIRST!!>>>>>>ANY AND ALL CAM MANUFACTURERS WILL need more info than the common, request for....
"I want a LUMPY IDLE SOUND and a FASTER CAR, whats the best cam... so it sure helps if you have as much valid info about your car handy as you can "
crane (386)310-4875
crower 619.661.6477
erson 800-641-7920
lunati..662-892-1500
ISKY 323.770.0930
clay smith 714-523-0530
FREE software
http://www.camquest.com/
http://www.popularhotrodding.com/tech/0 ... ewall.html
there are quite useful ,cam selection soft ware programs that get you in the ball park, but the final selection is based on far more factors than most of those software programs address
http://www.camquest.com/
write a list of all factors that will influence the cam selection choice, CALL AT LEAST 6-9 DIFFERENT CAM MANUFACTURERS, 7-9 WILL BE EVEN BETTER!,
DON,T LIE tell them EXACTLY what you expect and what you have currently ,installed,
and that the cam must work with NOW, NOT what you intend to install later.
DO NOT DISCUSS IN ANY WAY WHAT ANY OTHER MANUFACTURER SUGGESTED,
OR THAT YOU'VE EVEN TALKED TO ANY OTHER MANUFACTURER
YES you NEED too KNOW your COMPRESSION RATIO, and all the other answers to the questions below BEFORE calling....knowing a few more things, than your want a lope in the engines idle and you want a fast car when your done, about your combo , like your static compression ratio, displacement, cylinder heads used, rocker ratio, max valve spring clearance, or coil bind, height, spring load rates, carb,size, if its a vacuum or manual secondary carb, intake manifold,(single or dual plane,) headers, dimensions, your car weight, tire diam., do you need to pass emission testing? are you racing the car or is it daily transportation,etc would sure help, in the cam selection process??
selecting a cam without knowing those factors, is rather like marrying a girl based only on the color of her hair brush, you might make a good match but the odds say your dreaming
car weigh?
rear gear ratio?
tire diam.
trans and gear ratios?
stall speed if its an auto?
displacement?
COMPRESSION RATIO
HEADS (flow numbers)(lift restrictions)
intake type
tire size
intended use
max rpms
launch rpms
MIMIMUM IDLE
fuel octane
carbs,mpfi? CFM
ETC.
knowing a few more things, than your want a lope in the engines idle and you want a fast car when your done, about your combo , like your static compression ratio, displacement, cylinder heads used, rocker ratio, max valve spring clearance, or coil bind, height, spring load rates, carb,size, if its a vacuum or manual secondary carb, intake manifold,(single or dual plane,) headers, dimensions, your car weight, tire diam., do you need to pass emission testing? are you racing the car or is it daily transportation,etc would sure help??
selecting a cam without knowing those factors is rather like marrying a girl based on the color of her hair brush, you might make a good match but the odds say your dreaming
AVERAGE the RESULTS FROM EACH manufacturers suggestion,as to lift, duration and LCA and buy the cam thats the closest match to that average
write down their recommended cam type,its lift, and duration at .050 and LCA.
read off the list to each manufactures tech guys,
b]but DON,T DISCUSS IN ANY WAY WHAT OTHER MANUFACTURERS SUGGESTED[/b]
AVERAGE THE RESULTING LIFT DURATION and LCA info from each cam, and buy the cam that's CLOSEST TOO THAT AVERAGE, (ALL the MAJOR MANUFACTURERS HAVE DECENT CAMS) this tends to give consistently good results
http://www.cranecams.com/userfiles/PP08 ... ePages.pdf
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.
and the linked chart info, use both as a base line, but remember to call at least 5-7 cam company's and 7-9 would be even better as it virtually eliminates the chances of some moron giving you bad info, that will screw up your cam selection
and if you call many cam companies the tech guy you'll talk to will simply asked questions so he can fill in blanks on software programs, because he may not know squat about the type of engine your building, and they darn sure have no way to check your engines clearances or valve train geometry, so thats up to YOU to get THAT correctly done!
keep in mind a cams main function is control of valve timing and lift, valve timing and lift control airflow thru the cylinder head ports,intake, and exhaust system and the displacement and compression ratio,,needs to be a factor in your calculations, then theres clearance issues ,in the valve train,that need to be addressed, and compression and the restrictions to flow in BOTH the intake tract and exhaust system need to be used in your cam selection calculations, one very common mistake, is over camming a combo, or not verifying clearances, this almost always reduces potential power and frequently results in parts breakage
DO NOT UNDER ANY CIRCUMSTANCES DISCUSS ANYTHING A DIFFERENT CAM COMPANYS TECH GUYS SAID WITH EACH OTHER CAM MANUFACTURERS TECH GUYS IT WILL ONLY SCREW UP YOUR RESULTS
heres free cam selection software to narrow your choices
just for grins put your info into this program, and don,t lie, and see what cam it suggests
http://www.camquest.com/
http://www.compcams.com/Pages/409/camquest-6.aspx
AS your displacement per cylinder increases the effective valve size per cubic inch decreases so you need a slightly tighter LSA and these charts should help.





heres a chart I found that I don,t fully agree with, I think its a bit conservative, by about 3%-5% on the required cam duration ,required to avoid detonation with todays crappy octane fuel, but it at least gives you a base to work from, but Id suggest selecting a bit more duration

software like the free comp cams software below[/color]
[/size]
http://www.projectpontiac.com/ppsite15/ ... calculator
http://www.hotrod.com/how-to/engine/113 ... -camshaft/
http://www.superchevy.com/how-to/49224- ... gine-cams/
http://www.superchevy.com/how-to/148-04 ... m#cxrecs_s
http://www.superchevy.com/how-to/engine ... m#cxrecs_s
viewtopic.php?f=52&t=155&p=189#p189
http://www.superchevy.com/how-to/engine ... t#cxrecs_s
http://www.superchevy.com/how-to/148-03 ... t#cxrecs_s
http://www.compcams.com/Camquest/default.asp
but its almost always a good idea to get info from at least 6-7 sources, because you need to compensate for the occasional bad bits of info,
its not all that hard to calculate ,approximately the most efficient cam lift, duration, and LSA of a cam in an engine, if you know the cars tire diam. car weight, drive train gear ratios, engine compression displacement, head flow numbers,port cross sectional area, valve size, and a dozen other factors, its just that very few people that even understand what they need to look at and how each factor effects the combo,take the time and effort to do so , even the cam company Techs rarely bother, to factor in all the related components, but if you were to call lets say 7 cam companies and lets just as an example say that these were the suggested cams,
READ THESE LINK s
viewtopic.php?f=52&t=324
viewtopic.php?f=52&t=1070
USE THIS SOFTWARE TOOL
http://www.compcams.com/Camquest/default.asp
lets just say you got THESE HYPOTHETICAL EXAMPLES as suggested cams
(1) 245 /245 dur 106 lsa
(2) 255/260 dur 108 LSA
(3)252/258 dur 110 lsa
(4) 260/267 dur 112 lsa
(5) 246/249 dur 112 lsa
(6)250./250 dur 110 lsa
(7) 260/270 dur 106 lsa
your average would be
253/257 dur 109 .618/.630 , so you could reasonably assume that you would be very close to correct if you selected a cam with close to those specs, cam #(3) IN THIS CASE COMES CLOSE but look at the range, suggested 245 all the way to 260 , intake duration and 106-112 LSA ,thats fully 15 degrees spread in intake duration and 6 degrees in LSA, is it any wonder that most guys have a problem selecting cams when theres that much latitude in even what the cam tech guys suggest, let alone the guys on the internet who may be far less knowledgeable and just suggesting what they read worked in some magazine article on an engine that was only slightly similar designed for a car and drive train that bore little resemblance to your current application, thats why I always suggest getting a few cam company tech guys input, and by averaging the results you can effectively find and easily see , the OFF THE WALL SUGGESTIONS, and YES , RARELY SOME TECH SUPPORT GUYS SEEM TO BE CLUELESS MORONS
IVE had best results sticking with CRANE,CROWER, and ERSON generally
given a choice between two similar cams for a street car, selecting the lower duration, wider LSA and LOWER lift generally produces a better more durable combo for a daily driver car engine, or put a different way trading increased durability and lower stress over a bit more peak horsepower is rarely a bad idea if your dependent on the car for transportation
read the links below as they hold a great deal more important info [/color]
viewtopic.php?f=52&t=155&p=189#p189
viewtopic.php?f=52&t=181
http://www.compcams.com/Community/Artic ... 2026144213
http://www.aa1car.com/library/camshafts.htm
http://www.aera.org/ep/downloads/ep1/EP012008_34-40.pdf
http://www.hotrod.com/techarticles/113_ ... index.html
viewtopic.php?f=52&t=82
read thru these linked threads, as they will prove very useful
viewtopic.php?f=52&t=282
viewtopic.php?f=52&t=324
posting.php?mode=edit&f=52&p=189
viewtopic.php?f=52&t=425
viewtopic.php?f=52&t=904
http://www.crankshaftcoalition.com/wiki ... patibility
viewtopic.php?f=52&t=90&p=114#p114
http://www.crankshaftcoalition.com/wiki ... ationships
look you may not want too hear this but...IF YOU FOLLOW the advice BELOW EXACTLY, you'll have a decent cam, ignore it and your very likely to find you've selected a cam that won,t run correctly in YOUR APPLICATION
heres a semi-fool proof method
THERE'S A GOOD DEAL MORE INFO, and several sources for cams IN THE Links BELOW
viewtopic.php?f=52&t=399
viewtopic.php?f=52&t=553
http://www.aa1car.com/library/camshafts.htm
http://www.compcams.com/Technical/FAQ/C ... stions.asp
http://www.camcraft-cams.com/index.php? ... ting-a-cam
http://www.chevyhiperformance.com/techa ... index.html
http://www.cranecams.com/?show=faq&id=2
keep in mind solid lifters generally have an rpm advantage and roller cams generally out perform flat tappet designs but cost more
http://www.crower.com/
http://www.cranecams.com/
http://www.mr-gasket.com/pdf/Chevrolet.pdf
http://www.lunaticams.com/
http://www.chetherbert.com/newchet.html
http://www.howardscams.com/index-2.html
http://www.iskycams.com/
http://www.reedcams.com/
http://www.schneidercams.com/cams/20.htm
http://www.lazercams.com/CamTables.html
http://www.bulletcams.com/BulletCatalog.htm
http://www.englecams.com/
you should also keep in mind that a roller cam valve train with the same lift and duration can provide a good deal more port flow and resulting power.


but even roller cams can wipe out lobes if the valve train components or valve train lubrication,and geometry is not set up correctly


NO! ONE SIZE LARGER WON,T GENERALLY WORK BETTER, IN FACT ITS FAR MORE LIKELY TO BE A HUGE P.I.T.A to DRIVE AND HURT PERFORMANCE .
If your re-building a known combo,the questions that really should be asked here......
were you completely happy with the old cam or did you feel you wanted more upper or lower rpm band torque, did you like the way the engine ran, or did you feel it needed some tweaking?.....
what would you have liked to be changed about the power band when the old grind was in use?
BTW are you aware that reducing cams lift and valve spring load rates /pressures, and the degree of the aggressive cam ramp acceleration tends to increase durability in valve train components? yes it may cost you some hp, but it may be a good trade for increased durability
its critical that the converter stall speed and rear gear ratio match the cam timing and compression ratio if its an AUTO TRANSMISSION,......
MORE than if you have a manual trans, which is far more flexible as to what it will function with.
but having the rear gear ratio and compression ratio match the cam is mandatory for good results
and the larger the displacement and the better the heads flow the more likely it is that you'll find both good low rpm tq and mid to upper rpm hp you'll want in a street/strip combo, Ive seen many bad combos put together due to selecting a cam based on, the flawed logic
(well my buddies running cam (X) his car runs good...and I want to beat him so ILL buy the NEXT more aggressive cam with just a bit more duration and outrun him)
in most cases you'll be far better off, researching and selecting a combo with better cylinder heads, intake flow rates and larger displacement, rather than trying to go with a wilder cam.
remember your rarely going to make a huge improvement in hp per cubic inch with cam upgrades once you've reached about 1.25 hp per cubic inch displacement, but increasing the displacement, compression ratio and DISPLACEMENT tends to give a good boost over similar combos with lower displacement/cpr and head flow rates
if a 350 with 9.5:1 cpr that makes 1.25 hp per cubic inch that's 437 hp
build a similar stroker combo that has 401 cubic inches and 10.5:1 cpr and your far more likely to have about 520hp based on similar components
(the same 1.25 hp per cubic inch plus .04 increased tq due to the higher cpr and increased stroke ) plus all that at a slightly LOWER rpm that's easier on the valve train stress.
you might want to remember that a restrictive exhaust will kill much of the power potential, so decent TUNED headers and a low restriction exhaust is a necessary part of any build, and unless you can maintain the correct fuel/air ratio you can,t make good hp, so matching the fuel delivery and injector size to the applications mandatory
http://www.digitalcorvettes.com/forums/showthread.php?t=39010
http://www.compcams.com/Camquest/default.asp
comp cams is now offering a free cam selection software,THIS IS A USEFUL TOOL, this is useful in seeing the lift/duration/LCA they suggest for your application, in most cases they get fairly close so its a tool thats useful, now you don,t necessarily need to buy a COMP CAM but a cam with a similar lift/duration/LCA from your favorite manufacturer probably should be fairly close to whats recommended
willing to spend a few bucks ,want far more detailed results and a program requireing FAR more detailed input??
http://www.auto-ware.com/software/eap/eap.htm