semi fool proof cam sellection

grumpyvette

Administrator
Staff member
you can start with this, the SIX cam manufacturers POSTED OR LINKED BELOW that have proven to be dependable, the soft ware below might prove useful, so use it to get a base line
INFO YOU NEED IF YOUR selecting the correct cam for YOUR combo
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
https://www.crower.com/camshafts.html?cat=854

erson 800-641-7920
http://www.pbm-erson.com/UserFiles/Documents/Catalogs/2013 erson catalog.pdf

lunati..662-892-1500
http://www.lunatipower.com/Performance-Cams.aspx

ISKY 323.770.0930

clay smith 714-523-0530

herbert cams 714-491 -2267

duration_v_rpm_range_wintakemanifold01_b2df3f98be614a599705bb1f0b557d37f1804ad2.jpg

camcomp_dde0b24eebe620648f972b4209584cb660843f2a.jpg
LSAChart01.jpg




USE THE CALCULATORS
http://www.rbracing-rsr.com/runnertorquecalc.html
http://www.wallaceracing.com/chokepoint.php
http://www.wallaceracing.com/header_length.php
http://www.wallaceracing.com/chokepoint.php
http://www.rbracing-rsr.com/runnertorquecalc.html
http://www.velocity-of-sound.com/velocity_of_sound/calculator1.htm
FREE cam selection software
(while it may get you roughly in the ball park as far as duration, its not especially accurate in my opinion)
http://www.camquest.com/

http://www.popularhotrodding.com/tech/0 ... ewall.html

http://garage.grumpysperformance.co...ing-camshaft-for-specific-applications.10162/

http://garage.grumpysperformance.com/index.php?threads/cam-wear-articles-you-need-to-read.282/

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, so I would not trust these cheap software programs to be fairly accurate in most cases
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!, ask about warrantee, and billet quality and options like extra hardened, or polished billets or better quality lifters, youll tend to get the quality level you pay for, so don,t expect supper bargains on top quality components, and it makes little sense to save $100 on the total cost if youll have to pull the engine apart later and replace a worn or broken component
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??
on the street youll almost always find that the lower duration cam in the choice between two similar cams will in the long term be a slightly more useful choice.
(the simple reason why is that most street cars spend the vast majority of the time operating well below 4500-5000 rpm, and lower and mid rpm torque not peak hp is used far more often) it hardly makes sense to build any engine to produce its peak power in the rpm range you,ll rarely use. and the extra duration will generally reduce the low and mid rpm torque you use the vast majority of the time, in exchange for a bit more peak power you'll rarely access.
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

tell them your

car weigh?
rear gear ratio?
tire diam.
trans and gear ratios?
stall speed if its an auto?
displacement?
quench distance, head gasket thickness
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
don,t be afraid to ask for suggestions on how to improve the combo and ask if in their opinion your ignoring some factor, that cold help improve the engine, or doing something wrong
AVERAGE the RESULTS FROM EACH manufacturers suggestion,as to lift, duration and LCA and buy the cam thats the closest match to that average
after talking to each tech from each company
write down EACH CAM MANUFACTURERS , recommended cam type,
its lift, and duration at .050 and LCA.


REMEMBER!

if you have a problem with a component or need info on how to test or install a part or want to purchase a part and need details or choices explained in detail..
have you ever called some company and talked to some sales guy that was rather obviously reading the info off the catalog page about the part you wanted info on,
theres going to be 99 times out of 100 some guy answering the phone that is not an engineer or some guy that fully understands the way the product is made,
potentially being used or has any concept about its stress dimensions or operational conditions.
that does not necessarily mean the guys in the tech department , sales department or manufacturing departments are all totally clueless,
there are generally a few people in any company that really know all the details and are fully experienced,
those peoples time is worth far more to the company than the typical minimum wage zombie answering the incoming call traffic.
if you have a question,
start the call by asking the guy answering the call for his first and last name, always be polite, never waste the guys time

write it down
now you may or may not ever want to talk to this guy again, but its will at least tend to make them think hard about treating you like an idiot, or slamming the phone down,
or disconnecting you if they don,t want to answer questions.
\address the guy by his NAME several times, during the conversation, and ask his function in the company.
if he can,t answer your question ask if they have an engineer or more tech savvy guy you can talk too...
start the call by asking the guy answering the call for his first and last name,
and direct phone extension number if you can.always be polite, never waste the guys time
write it down address the guy by his NAME several times, during the conversation,
that way you can in the future bye-pass the answering desk zombies if you can build a friendly conversation,
but don,t waste the guys time and be sure you thank him by name at the conclusion of any conversation if he helps you.
keep a note book with company names phone numbers and the skilled tech guys as a future reference,
and remember the guys answering the incoming calls are rarely knowledgeable or even give a crap about the company..
that does not indicate the guys in engineering that know how things actually are made and function are anywhere near as useless as the phone desk guys.
its simply a fact that, a company can produce quality parts but have hired some real clowns to answer phones



read the data and average it off the list to each manufactures tech guys,once you have 6-7 to average
but DON,T DISCUSS IN ANY WAY WHAT OTHER MANUFACTURERS SUGGESTED
with the other tech guys or even hint you talked with anyone else simply give them the basic info and let them talk, don,t interrupt or ask questions that indicate you talked to other companys as thats sure to sway the average end result.


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
lsadig.jpg
lclcomp.png

generally its best to purchase all the listed components in a cam installation kit (cam, lifters,valve springs, etc. ) from a single manufacturer as mixing parts, sources or brands,
allows the cam manufacturer to void the warranty, even if the parts in the kit they sell are either identical or inferior to,
the individually purchased components you individually sourced. keep in mind most manufacturers will have tested parts compatibility ,
so they are reasonably sure the components they sell in the kit will work, that can,t be always assumed,
with randomly matched parts even if those parts are good quality.



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.

0607phr_11_z+camshaft_basics+lobe_centerline_angle_determination_chart.jpg

Duration_v_RPM-Range_wIntakeManifold01.jpg

craneq2.gif

Compression_Power.gif

definition.jpg

postiongraph.jpg

Ive built enough engines that I think I can post a bit of info regarding the effect of the need to consider dynamic compression, in the engine planing


fact
usable torque the engine produces tends to go up as cylinder pressure increases
fact
your fuels OCTANE LEVEL LIMITATIONS, or tolerance, to heat & rapid compression before you tend to get into potential detonation,from the fuel igniting from rapidly induced heat and compression, issues limits the effective useful compression.
fact
uncontrolled detonation will rather quickly damage pistons and rings
fact
cylinder pressure is greatly influenced by the cylinders,displacement, and valve timing as well as the static compression ratio
fact
on a N/A engine you'll rarely if ever exceed the static compression, with the effective dynamic compression, but you can markedly reduce it with cam timing changes, that delay the valves closing as the piston compresses the cylinder volume.

compec3.png

cylinderpresgr.png

cyl_pressure_vs_crank_angle.jpg

camcomp.jpg

lclcomp.png

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

CamUsageChart01.jpg

software like the free comp cams software below[/color]
[/size]

http://garage.grumpysperformance.co...mbers-or-a-good-street-combo-your-after.5078/

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



http://garage.grumpysperformance.co...s-and-a-few-similar-aftermarket.133/#post-163

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


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]



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



read thru these linked threads, as they will prove very useful





posting.php?mode=edit&f=52&p=189



http://www.crankshaftcoalition.com/wiki ... patibility



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



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.pbm-erson.com/UserFiles/Documents/Erson_Tech/Erson-custom-cams-tech.pdf

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.

flatvsroller.jpg

FlatVsRollerChart.gif

but even roller cams can wipe out lobes if the valve train components or valve train lubrication,and geometry is not set up correctly
camlobe1.jpg

camlobe2.jpg

camsd3a.jpg

camsd2z.jpg

camsd1a.jpg



vincama.png


READ THE LINKED INFO CAREFULLY
http://garage.grumpysperformance.co...ped-nose-cam-in-early-block.14182/#post-71937

http://garage.grumpysperformance.com/index.php?threads/semi-fool-proof-cam-sellection.82/

http://garage.grumpysperformance.co...-street-roller-cam-selection.5709/#post-46850

http://garage.grumpysperformance.co...a-better-cam-to-a-zz3-350-sbc.182/#post-26013
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.
keep in mind a" LAZY " cam, might be far better for low wear and increased durability,
engineers that design a cam and valve train, need to know whats expected,
any cam may be significantly easier on the valve train and durability may be greatly enhanced or extended or peak power might be the goal,
minor changes can have very significant effects on durability without changing power very much,
both CRANE AND CROWER are rather well known of tending too design cams that might sacrifice a couple peak horsepower,
if it required to significantly boost long term durability and reducer the chances of valve train stress levels,
some other company's have a few cam lobe designs that are right at or even at times in some rpm ranges a bit past the limits,
of what most builders might see as reasonable for longer term durability,
they seem more concerned with being able to produce the best possible peak power,
even if doing so might reduce the engines longer term life expectancy.
a cam designed for drag racing that might be expected to make peak power for less than 15 seconds at a time will be a great deal different than one in an engine designed to run the 24 hour race at le-mans even if both cars ran in a car with a similar engine family, and certainly both would be designed far differently than a cam designed to run issue free for 100K miles
a difference in philosophy ,
one group thinks you have to finish the race to win,
most guys don,t have unlimited cash so lets design something that will last a long time without issues!
the other group thinks, youll never win unless your making the most power available,
and race engines get torn down , inspected and re-built regularly so push the limits
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.





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.projectpontiac.com/ppsite15/compression-ratio-calculator

http://www.wallaceracing.com/dynamic-cr.php

http://www.rbracing-rsr.com/comprAdvHD.htm

http://performancetrends.com/Compression_Ratio_Calculator_V2.3.htm

http://www.wallaceracing.com/cr_test2.php

http://www.pcengines.com.au/calculators/Calculate dynamic Comp Ratio.htm

http://www.csgnetwork.com/compcalc.html

http://www.diamondracing.net/tools/

https://www.uempistons.com/index.php?main_page=calculators&type=comp

https://www.rbracing-rsr.com/compstaticcalc.html

http://www.auto-ware.com/software/eap/eap.htm
 
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I,ve had consistently good results from these suppliers , high lighted in green and would recommend them with no reservations, based on my experience, and have seen , good results with the others listed, or had limited but good results
most cam manufacturers will want some basic info similar to this crower cams info request sheet.

camformk1.png

lunati
http://www.lunatipower.com/

ISKY
http://www.iskycams.com/

BRODIX
http://www.brodix.com/heads/heads.html

ERSON
http://www.pbm-erson.com/store.php?catId=327
http://usaperform.com/-c-154_206.html


CROWER'
http://www.crower.com/

KINSLER
http://www.kinsler.com/page--Home-Page--13.html

HERBERT
http://www.dougherbert.com/

DART
http://www.dartheads.com/products/engin ... big-blocks

CRANE CAMS
(I did a ton of business with the old crane cams, Ive not yet built a firm background with the new company but so far they seem competent)
http://www.cranecams.com/?show=technicalhelp

http://www.jonescams.com/2006catalog_002.htm
Ive heard good things but never used these guys

ELGIN
http://catalog.elginind.com/download/PROSTOCK.PDF


are some other companies Ive had nothing but good results from
CROWER
http://www.crower.com/media/pdf/chevrolet.pdf

CRANE
http://www.cranecams.com/uploads/catalog/Crane Cams Master Catalog.pdf

ERSON
http://www.pbm-erson.com/UserFiles/Documents/Catalogs/2013 erson catalog.pdf
http://usaperform.com/-c-154_206.html

HOWARD
http://www.howardscams.com/howards2015.pdf
https://howardscams.com/c-1268612-camshafts-and-cam-lifter-sets.html

HERBERT
http://www.herbertcams.com/herbert-cams-cam-kits/

ENGLE
http://www.englecams.com/downloads/2010_engle_catalog.pdf
 
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OK lets look at a few basic facts, and how you select the correct cam, for YOUR particular engine.
KEEP IN MIND that a good deal of the power in any engine combo will be the result of how efficiently you blend factors like,
EFFECTIVE COMPRESSION,vs fuel octane
CYLINDER HEAD FLOW rates vs displacement
and
EXHAUST scavenging efficiency.(cam timing)
theres a good deal of math involved, that can be used to accurately predict the results but there's also an ART and SKILL to tuning and engine assembly, and experience goes a long way there.
and yes a slight mis-match of components, not getting the clearances correct, or a few degrees of cam duration,plus or minus from what the engine needs, and a few cfm difference in intake or exhaust restriction,flow, a few extra fractions of an inch of valve lift, a better or worse multi angle valve job and your up or down 60-80 hp...

the first consideration is always to verify you’ve got enough internal clearance or you’ll need to modify the current engine so it can physically have the cam installed(you'll want to check ,piston to valve and valve spring .coil bind, retainer to valve seal ETC.)to run the resulting valve lift and duration, valve spring load rates and that there’s no physical limitations in the valve train or other engine components that can cause problems.


Next you'll need to verify that the engines displacement and compression, port cross sectional area and potential exhaust flow and ignition timing will correctly function with the cam selected, and the engines quench distance are all designed to enhance or at least be compatible with the cam selection, and fuel octane.

Next you’ll want to verify the drive train will hold the car in the intended rpm range the great majority of the time, so you can access the power curve potentially produced, and several dozen more factors but lets just look at TWO that may concern you here

Dynamic compression (cam timing & compression) & your cars drive train gear ratios

Heres a very useful chart from crower that gives you the cam timing at .050 lift from duration and LSA (lobe separation angle)
http://www.crower.com/valve-timing-chart/

heres two dynamic compression ratio, calculators (average the results)
http://www.kb-silvolite.com/calc.php?action=comp2

http://www.wallaceracing.com/dynamic-cr.php

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.
definition.jpg

postiongraph.jpg

lsadig.jpg

camcomp.jpg


https://www.hotrod.com/articles/wrong-camshaft-for-application/
0607phr_11_z+camshaft_basics+lobe_centerline_angle_determination_chart.jpg


Duration_v_RPM-Range_wIntakeManifold01.jpg


CamUsageChart01.jpg

First Id point out that nearly everyone occasionally confuses or at least makes the mistake of using the wrong abbreviation, (LSA, and LCA) these are terms,that are almost, at least in many discussions interchangeable. which they are not.
LSA =LOBE SEPARATION ANGLE ........LSA is ground into the cam during manufactured, and can,t change,


LOBE SEPARATION ANGLE

Above 114 Deg. = Extremely Wide
114-112 Deg. = Wide
112-110 Deg. = Moderately Wide
110-108 Deg. = Moderate
108-106 Deg. = Moderately Tight
106-104 Deg. = Tight
Below 104 Deg. = Extremely Tight

VARYING LOBE SEPARATION ANGLE
Tighten.................................................Widen
Moves Torque to Lower RPM.................Raise Torque to Higher RPM
Increases Maximum Torque..................Reduces Maximum Torque
Narrow Power Band..............................Broadens Power Band
Builds Higher Cylinder Pressure............Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock.........Decrease Chance of Engine Knock.
Increase Cranking Compression...........Decrease Cranking Compression
Increase Effective Compression............Decrease Effective Compression
Idle Vacuum is Reduced........................Idle Vacuum is Increased
Idle Quality Suffers...............................Idle Quality Improves
Open Valve-Overlap Increases.............Open Valve-Overlap Decreases
Closed Valve-Overlap Increases...........Closed Valve-Overlap Decreases
Natural EGR Effect Increases................Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance...Increases Piston-to-Valve Clearance
[color:red]LCA =(LOBE CENTER ANGLES)remember lobe center angles can be changed thru indexing the cam when degreeing it in[/color]
ADVANCING / RETARDING CAM TIMING

KEEP IN MIND MANY CAMS ARE FACTORY SET UP TO BE 4 DEGREES ADVANCED if INSTALLED DOT-TO-DOT

ADVANCING.
Begins Intake Event Sooner........................
Open Intake Valve Sooner..........................
Builds More Low-End Torque.......................
Decrease Piston-Intake Valve Clearance....
Increase Piston-Exhaust Valve Clearance...

RETARDING
Delays Intake Event Closes Intake
Keeps Intake Valve Open Later
Builds More High-End Power
Increase Piston-Intake Valve Clearance
Decrease Piston-Exhaust Valve Clearance


lcadc1.jpg


"Lobe Centerline Angle Determination Chart
To use this chart, first establish the number of cubes in the INDIVIDUAL cylinder, per inch of valve diameter. To get this number, divide the engine displacement by the number of cylinders, then by the intake valve diameter. Find that number on the vertical axis, then move across to the green line. At the intersection point, drop down to the base and read off the LCA required. Because big-block Chevys have angled valves, they need to have about 2 degrees less than this chart indicates."

LSA_01.jpg
0810chp_05_z+comp_cams_camshaft_technology_insite_tech+lobe_separation_angle.jpg


116_0403_basic_10_z.jpg


http://forum.grumpysperformance.com/viewtopic.php?f=52&t=1070

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=480

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=2782&p=7215&hilit=+overlap#p7215

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=90

http://garage.grumpysperformance.co...vs-lsa-lobe-seperation-angle.3816/#post-10147

http://garage.grumpysperformance.com/index.php?threads/cam-wear-articles-you-need-to-read.282/

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=2782&p=7433&hilit=+overlap#p7433[/quote]

http://garage.grumpysperformance.co...chevy-cams-and-a-few-similar-aftermarket.133/


Good related threads that all give you valid additional info on selecting the correct cam choice YES I KNOW its a good deal more to read but KNOWING what to look for and what the potential problems may be helps select the correct cam.


lower wear, less friction,less heat generated, higher lifter acceleration rates and allowing the valve to remain open longer, thus the ports to flow more volume in a given time frame at any given duration, make the roller cam potentially the more powerful choice

p174971_image_large.jpg


flatvsroller.jpg


FlatVsRollerChart.gif





 
Last edited by a moderator:
Fuel Injected Engine Camshafts in nearly stock engines


For a camshaft to work in a fuel injected application, it needs to make a good vacuum signal.



To create a vacuum signal, that stands a reasonable chance at working in an application without having to re-flash the ECM computer, a camshaft needs to be:

A) Short duration, 220-222 degrees @ .050” maximum.

B) Wide lobe separation/centers, 112 to 114 degrees minimum.

Do not attempt to install a camshaft with a 108 lobe separation in a fuel injected engine, unless you are planning to re-program the ECM computer.

There are camshafts that are ground to work within the stock ECM computer parameters. Usually these camshafts have 208/208 degrees duration @.050” (intake/exhaust) and 112 degrees of lobe separation, or 208/214 duration with a 114 L/C.

Both of these camshafts would be designed to function in stock cid engines/stock compression and stock computer programming.

However, if the cubic inches of the engine or compression ratio is larger than stock, the camshaft grind needs to grow accordingly and a custom camshaft would then be in order.

Also, having the computer re-programmed/re-flashed is recommended with any camshaft change, even the “no hassle/safe” type grinds.

While the camshaft may work with the stock fuel/timing curve programmed into the ECM unit, it will not be working at its optimum level. Think of it along the lines of taking a performance carburetor out of the box, bolting it onto the engine, hooking up the fuel lines and running it. It may run but without tuning/jetting the carburetor to the engine, but it will not work to its full potential.

While we are on this subject, there are some engines that you need to be wary of:

* Late ‘80s-Early ‘90s 350 Chevrolets with a K engine code and an idle speed of 500 rpm (TBI).

• Early Ford V8s with the Speed Density fuel injection.

• Dodge Magnum V8s

• Any fuel injected application where the customer wants a loud/radical idle.

These engines/computer combinations have very special camshaft grind requirements, so should you run into one of these combinations, it would be best to call your camshaft manufacturer for a recommendation.

–Tech Tip courtesy of PBM-Erson Cams
 
if your building a 383 sbc these links and sub links will help

lsadig.jpg
lclcomp.png


Engine Types | General Tips
stepnoser1.jpg


Starting in 1987, GM began using a hydraulic roller cam in their production car engines.
This required a cam thrust plate on the front of the block.
The step in the nose of this cam (left) identifies it as a cam intended for use in a production roller cam block.

If your ever in doubt, about the correct timing chain application,
CALL THE TECH GUYS AT CLOYES:D

cloyes tech dept 1-479-646-1662 EXT 228

with the older style non-step nose cam, in the newer style "08" block, you will NOT use the retainer plate
you should use a cloyes 9-3100 timing chain, set

https://www.summitracing.com/parts/clo-9-3100


http://www.compcams.com/Pages/412/general-motors-technical-info.aspx

Small Block and Big Block Chevrolet engines have become legendary since they were introduced over 50 years ago. The people at COMP Cams®, along with a lot of top engine builders, have spent many years improving these and other Chevrolet powerplants. We know the basics, and the basics are important. We have also learned a few tricks along the way.

If you’re rebuilding an engine, it will be worth your while beforehand to either read our books or watch our videos on the subject. If you need more help or have any questions, call our CAM HELP® line at 1-800-999-0853.



Small Block V8
There are several varieties of small block engines currently in use in the aftermarket. Although they mostly use the same block, the cylinder heads are very different and require totally different camshafts. The valve arrangement in the heads is different, and therefore the lobe placement on the camshafts must coincide with the head you are using. The “54” is the first cam to completely stray from the original design. It is .300” larger in diameter.

image004.jpg

The nose of the standard early model cam “12” is very different from the later model hydraulic roller “08”. The nose of the hydraulic roller “08” is necked down to accommodate the cam retention plate. The “07” is an LT1/LT4 shaft which has a longer dowel pin and a center hole for the distributor. Be sure to check the diameter and depth of the hole in the front, as well as the length of the dowel pin.


Standard Small Block Chevy -uses “12” Prefix
This is the basic engine configuration found on all small blocks from 1955 until 1987, when Chevrolet introduced the roller cam. It’s important to note that the 1955-1957 versions require an oiling groove to be machined into the rear cam journal, but the camshafts are interchangeable.



OE Hydraulic Roller Small Block -uses “08” Prefix
Beginning in 1987 small block V8 engines were equipped with hydraulic roller cams. There are differences in the block to accommodate a cam retention thrust plate and antirotation mechanism for the lifters. These blocks are identifiable by bolt holes for a cam retention plate behind the upper timing sprocket, as well as bosses and tapped holes in the lifter valley.

The camshafts on these engines have a step nose and smaller bolt pattern on the front of the cam. An earlier model camshaft may be used in these blocks by using the appropriate timing chain set and adding a thrust button when using a roller cam.



LT1 and LT4 Engine -uses “07” Prefix
These engines are, as far as the camshaft is concerned, essentially the same as the hydraulic roller engines, with one exception. The distributor is driven from the front of the cam, requiring some changes in the cam core. There is a deeper pilot hole in the front of the cam, as well as a longer dowel pin to locate this drive. These engines require a special timing chain set, and they utilize a self-aligning rocker arm. COMP Cams® LT1 and LT4 Magnum rocker arms can be found on page 268.



Buick Head, Splayed Valve GM and Dart Buick
Small Block, -uses “19” Prefix

Buick made a small block cylinder head in the early 1980's which fits a small block. This head was made by Dart and is still very common in drag racing and some oval track racing. The camshaft is different because of the different valve arrangement in the head. The valve arrangement of Splayed Valve GM and Dart Buick heads are identical to the Buick, so the camshaft is the same.



SB2 -uses “03” & “04” Prefixes
One of the latest versions of true race engines from GM is the SB2. It uses a totally different valve arrangement, and therefore a different core. One major item that changed is that there is a special SB2 block. The lifter bore spacing and lifter angle are different, specifically to work with a flat tappet for cup applications. When using a standard block and SB2 head, use prefix “03”. When using the SB2 block and the SB2 head, use prefix “04”.



GM Gen III/LS1/LS2/LS6 -uses “54” Prefix
This engine is the first real departure from GM's original small block design. Almost none of the parts carry over from previous engines. The camshaft is a steel roller cam, approximately 4” shorter and .300” larger in diameter, so there should be no problem with misapplications.



Big Block -uses “11” Prefix, Gen VI Big Block -uses “01” Prefix, 8.1L Big Block -uses “46” Prefix
This engine was introduced in 1965 and with the exception of some of the very early 1965-1966 models, which had an oiling groove in the rear journal, the camshafts are interchangeable. This includes all of the big blocks, including the Mark V, with just about any style cylinder head until the 454-502 Gen VI was introduced in 1996. This engine is similar to the earlier standard big block. The heads are interchangeable, but there is nonadjustable valve train. It is equipped with a hydraulic roller camshaft. There is a positive camshaft retaining plate on the front, and the nose of the cam is stepped down to accept this plate. The lifter bosses are taller to accommodate the lifter anti-rotation plates. This engine will require a special timing chain set.



Older Engines
The very first 1955-1957 265 c.i. small blocks had a unique oiling system. The same holds true for the first 1965 and 1966 396/427 big blocks. When one of these blocks is used, it is necessary to machine a small groove in the rear journal of the cam to allow oil flow to the top of the engine. COMP Cams® camshafts come without this groove, so it is important to check the vintage of your block prior to camshaft installation. COMP Cams® can perform this operation or supply the specs to you for local machining.



image005.jpg

This chart shows the valve arrangement of typical Chevrolet cylinder heads. You can see each of these will require a different camshaft.




Small Block Spring Pockets
When machining a small block head for larger diameter valve springs, be aware that the area around the spring pockets in the head is very thin, especially the end or outboard exhaust. Care must be taken not to machine through the head when increasing the diameter of the spring pocket. You can round the edge of the cutter used to machine the pocket to resemble the diameter of the wire in the valve spring. Another way is to insert a .030” standard 1.250” diameter spring shim in the pocket prior to machining and cut only down to that point. The safest way is to seek professional help before ruining the heads.



Studs
When you are using a high performance camshaft and have problems with the valves not staying properly adjusted, one of the first things to check is the rocker arm studs. Most early model small block heads utilize pressed in studs. When high spring loads and high engine speeds are used with these stock type studs, they tend to pull out of the heads. You can check for this by laying a straight edge across the top of the studs to see if any of the studs are too high and out of alignment. If so, the heads should be removed and machined for screw in studs.

Factory small blocks were equipped with 3/8” studs and rocker arms. One of the most common practices on these engines is to replace these with larger 7/16” versions similar to those found on the big block engines. This is a simple conversion but requires a roller trunion rocker arm. See page 269.

In 1991 Chevrolet introduced the Mark V Big Block, which comes from the factory with a non-adjustable valve train. When changing to a non stock camshaft, the valve train must be converted to adjustable. We developed a special stud (Part #4514-16, page 277) to convert the heads with no required machining. Also on page 275 is a series of Magnum rocker arm kits engineered specifically for these engines that include this stud.



Flat Tappet Break-In
All flat tappet cams will require special attention during the break-in process. Due to recent changes in motor oil formulas, a switch to a diesel or non-synthetic racing motor oil in combination with COMP Cams® #159 Camshaft Break In Lube is mandatory in order to avoid camshaft failure during break in. Cams requiring dual valve springs during normal operation will also require that the inner valve spring be removed during break in so that critical lifter rotation can be established. The appropriate COMP Cams® lifters, and correct valve springs, rocker arms, and pushrods are also absolutely essential to ensure long camshaft life. Please refer to the instructions in your cam box for complete procedures or page for our tech bulletin on the topic If ever in doubt, please call the COMP Cams® CAM HELP® line at 1-800-999-0853.


Roller Cams
Several points must be considered when installing a roller cam in an earlier block designed for a flat tappet cam. Flat tappet cams are ground with taper on the lobes to force the cam to the rear of the engine. Roller cam lobes are ground flat, so a thrust button must be used to keep the camshaft to the rear of the block. Most racing roller cams are steel billet cams, which require an upgraded distributor gear. Most street roller and hydraulic roller camshafts are made from an austempered material which is compatible with the standard gear; however, COMP Cams® composite distributor gear is the best choice.


Hydraulic Roller Cams
When installing a hydraulic roller cam in an early model block, it is necessary to use a special hydraulic roller lifter with a link bar assembly to keep the lifters from rotating in their bores. In addition, appropriate- length pushrods must also be used. A roller lifter, being physically longer, has a pushrod seat that sits closer to the rocker arm than a flat tappet lifter pushrod seat –necessitating a shorter pushrod. A thrust button is required to keep the cam from “walking” forward in the block. A wear plate is also a required (though inexpensive) part, which serves to prevent the rear of the camshaft gear of the timing set from excessively wearing the engine block as it works to keep roller cam walk under control.

When installing a flat tappet cam in a block originally equipped with a hydraulic roller, it is necessary to change the entire system. The cam, lifters, pushrods and timing chain set must all be changed in this case, as none of the old parts will interchange.



Self Aligning Rail Rocker Arms
Originally, the small block engine used a machined slot in the head to guide the rocker arm on the valve. It has been common to enlarge this hole and install a guide plate when switching to a high performance valve train.
In 1988 with many models and later, on all engines, Chevrolet utilized a small alignment slot in the valve tip end of the rocker where it contacts the valve. Although there may be an alignment guide on the head, it is not hardened and is used only to align the pushrod during assembly. This guide may not be used with a standard non-aligning rocker arm. When building a high performance engine, we recommend that the alignment guides, pushrods and rocker arms be replaced with the earlier style parts. When building a mild street engine, COMP Cams® developed the Magnum and Pro Magnum Rocker Arms™ designed specifically for the late model self-aligning design.



High Ratio Rocker Arms
A higher than standard ratio rocker arm moves the pushrod closer to the rocker arm stud. This makes it necessary to check the clearance between the pushrod and the head where the pushrod passes through. This is a very common problem and should be carefully checked whenever a rocker arm ratio change or pushrod diameter change is made. We offer a special tool (Part #4710) to machine this on page 339.



Rocker Arm Geometry
Proper rocker arm geometry is required to ensure the maximum benefit from any cam design. Camshaft base circle, block deck height, cylinder head design and lifter design all contribute to possible errors in valve train geometry. It is simple to make compensation with pushrod length. Usually, a longer than stock pushrod will be necessary in a high performance engine, but care must be taken to choose the correct length.



Rocker Arm Slots
One of the most frequent problems encountered when changing to a high lift camshaft is the slot in the rocker arm will contact the rocker arm stud, resulting in camshaft, lifter, rocker arm and/or stud failure. This is prevalent on both small block and big block engines with stock rocker arms. Always check this and change to either a roller trunion rocker or a long slot rocker arm when contact is evident. COMP Cams® Magnum Rocker Arms are a good solution to this problem.





crankshaft coalition said:
http://www.crankshaftcoalition.com/wiki ... ationships

Camshaft/Compression Ratio relationships

by: Cobalt327, Crosley, Techinspector1
(Click here to edit this page anonymously, or register a username to be credited for your work.)

The final word in cam selection should always be determined by the grinder for your specific application. It's a free service offered by all cam manufacturers.

OK, now with that disclaimer in place, I will attempt to help you see how the SCR (static compression ratio) plays out with the cam timing. There may be a mathematical formula, but I'm not aware of it, so I just use what information I have available to me and try to figure it out from there. We will not get into DCR (dynamic compression ratio) here. That's a whole other subject for another time.

The main point to consider is the intake closing point after bottom dead center. That's what controls the amount of cylinder pressure the *motor will make. You don't make any compression at all until the intake valve closes.

Here is a list of camshafts taken from the Crane catalog that I refer to when I'm trying to get in the ballpark for matching the SCR to the IC point, taking into consideration the lobe separation angle and useful range of the camshaft. Again, this will only put you in the *ballpark and you should always lean on the manufacturer for a final decision.

First is the SCR range of the motor, then the intake and exhaust duration @ 0.050" tappet lift, then the lobe separation angle, then the intake closing point and finally the operating range. Now please, don't anyone take this as the final word on camshaft choice. I only posted it to help the OP understand the relationships and this is a very short list of the thousands and thousands of cam grinds that are available to you. This chart was taken from the catalog of small block Chevy grinds with emphasis on the 350 cubic inch motor. Be aware that larger displacement motors will tolerate more camshaft and smaller displacement motors will be less tolerant of more camshaft. In other words, with the proper choice of cam for a given set of conditions in a 350, the same cam will be milder in a 406 and wilder in a 302.

7.50-8.50........184/194....104....16....500-4000
7.75-8.75........194/204....104....21....800-4400
8.00-9.50........204/204....110....27....1000-4600
8.00-9.50........206/218....112....30....1200-5200
8.50-10.00......210/210....110....30....1400-5000
8.50-10.00......212/218....114....35....1600-5400
8.75-10.00......216/216....110....33....1600-5400
8.75-10.00......218/218....106....31....1800-5400
8.75-10.75......218/230....112....36....1800-5800
9.00-10.50......228/232....107....37....2800-6000
9.00-10.50......232/232....107....39....3000-6000
9.50-10.75......222/222....110....36....2000-5800
9.50-10.75......224/230....110....37....2200-6400
9.50-11.00......226/226....106....34....2400-6200
9.50-11.00......228/228....112....41....2800-6200
9.50-11.50......228/228....106....36....2800-6400
10.00-11.00....232/236....106....38....3000-6400
10.00-11.00....236/236....107....41....3200-6200
10.00-11.00....236/242....112....40....3200-6600
10.00-11.50....228/234....106....36....2800-6400
10.00-11.50....230/230....106....37....3000-6400
10.25-12.00....236/244....110....43....3000-6800
10.50-12.00....238/238....106....41....3200-6400
10.50-12.00....244/252....106....44....3400-7000
10.50-12.00....246/246....106....45....3400-7000

Notice that the range of operation (3400-3600 rpm) remains constant as the grind gets wilder. It simply moves up the scale with more duration and requires more static compression ratio to maintain the same cylinder pressure. The slug of air/fuel mixture running down the intake runner into the cylinder has inertia. Once it is moving, it tends to continue to move. Using this phenomenon to advantage, we can hold the intake valve open even after the piston has gone to bottom dead center, reversed its direction and is heading back up the bore. This is where the balancing act takes place, leaving the intake open so that the intake charge continues to pack the cylinder, even with the piston coming up the bore, but closing it soon enough so that the intake slug is not pushed back up the intake tract by the ascending piston. If we push the charge back up the tract by leaving the valve open too long, we get reversion at the carburetor throat. The venturis see air flow coming both ways and don't know whether to **** or go blind, so we get a rump-rump idle. It is the sound of a motor being very, very inefficient because the rpm at idle is out of the operating range of the cam. Once the revs get up into the cam's range, the motor will smooth out as it becomes more efficient.

Cams ground with a narrow lobe separation angle (LSA), such as 104/106 degrees will tend to build power quickly in the lower rpm range and then peter out higher up. A wider lobe separation angle such as 112/114 degrees will give up power at the bottom of the range for power higher up in the rpm. Most cam grinders will use a middle of the range 110/112 degrees for street motors. The wider angles would be helpful with nitrous oxide or a blower motor on alcohol (blower motor on gasoline works best at 110 degree LSA) or an EFI motor.

A rule of thumb that I use is that you need to begin considering a looser torque converter when the operating range of the camshaft hits 1400 rpm on the low part of the range. A looser converter will make any cam more driveable, even a stock cam. You won't have to stand on the brake at stop lights and the motor gets up into a useful rpm range more quickly. For instance, I'd be thinking of using a 2000 rpm stall converter with a stock cam just to make the car more driveable.

While we're on cams, I think most everyone knows that more cam requires more initial spark timing.
grumpyvette said:
First Id point out that nearly everyone occasionally confuses or at least makes the mistake of using the wrong abbreviation, (LSA, and LCA) these are terms,that are almost, at least in many discussions interchangeable. which they are not.
[color:red]LSA =LOBE SEPARATION ANGLE ........LSA is ground into the cam during manufactured, and can,t change,[/color]


LOBE SEPARATION ANGLE
Above 114 Deg. = Extremely Wide
114-112 Deg. = Wide
112-110 Deg. = Moderately Wide
110-108 Deg. = Moderate
108-106 Deg. = Moderately Tight
106-104 Deg. = Tight
Below 104 Deg. = Extremely Tight

VARYING LOBE SEPARATION ANGLE
Tighten.................................................Widen
Moves Torque to Lower RPM.................Raise Torque to Higher RPM
Increases Maximum Torque..................Reduces Maximum Torque
Narrow Power Band..............................Broadens Power Band
Builds Higher Cylinder Pressure............Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock.........Decrease Chance of Engine Knock.
Increase Cranking Compression...........Decrease Cranking Compression
Increase Effective Compression............Decrease Effective Compression
Idle Vacuum is Reduced........................Idle Vacuum is Increased
Idle Quality Suffers...............................Idle Quality Improves
Open Valve-Overlap Increases.............Open Valve-Overlap Decreases
Closed Valve-Overlap Increases...........Closed Valve-Overlap Decreases
Natural EGR Effect Increases................Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance...Increases Piston-to-Valve Clearance
[color:red]LCA =(LOBE CENTER ANGLES)remember lobe center angles can be changed thru indexing the cam when degreeing it in[/color]
ADVANCING / RETARDING CAM TIMING

KEEP IN MIND MANY CAMS ARE FACTORY SET UP TO BE 4 DEGREES ADVANCED if INSTALLED DOT-TO-DOT

ADVANCING.
Begins Intake Event Sooner........................
Open Intake Valve Sooner..........................
Builds More Low-End Torque.......................
Decrease Piston-Intake Valve Clearance....
Increase Piston-Exhaust Valve Clearance...

RETARDING
Delays Intake Event Closes Intake
Keeps Intake Valve Open Later
Builds More High-End Power
Increase Piston-Intake Valve Clearance
Decrease Piston-Exhaust Valve Clearance





LSA_01.jpg
0810chp_05_z+comp_cams_camshaft_technology_insite_tech+lobe_separation_angle.jpg


116_0403_basic_10_z.jpg


http://forum.grumpysperformance.com/viewtopic.php?f=52&t=1070

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=480

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=2782&p=7215&hilit=+overlap#p7215

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=90

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=2782&p=7433&hilit=+overlap#p7433

"EXAMPLE, OF A
very common mis- conception, is that a cam which is ground on a 108 degree lobe center. which has more overlap and will reduce your DCR due to greater overlap."

PROBABLY one of the MOST COMMON MYTHS
( is that overlap with a tight LSA bleeds off compression)
Overlap has nothing to due with DCR. A cam with 108 LSA will close the intake valve sooner on the compression stroke and create MORE cylinder pressure than a cam with 112 LSA. That assumes durations and cam lobe designs are the same of course "

this is correct

example
LOOK heres TWO cams IDENTICAL EXCEPT FOR THE LSA,(LOBE SEPARATION ANGLES) assuming both cams are installed with identical LCA (LOBE CENTER LINE ANGLE)remember lobe center angles can be changed thru indexing the cam when degreeing it in, LSA is ground into the cam during manufacture, the tighter LSA of the crane 110921 builds a bit more cylinder pressure and results in slightly more torque over a NARROWER rpm band so its better with a manual transmission, the crane 114681 with its wider LSA tends to work better with an auto trans with its wider torque band but very slightly lower peak torque, the crane 110921 has more overlap and better savaging in the mid rpm band, but it idles rougher at low rpms and that overlap doesn,t help if you use nitrous
COMPARE the TIMING

110921.jpg

110921q.jpg

narrower LSA, more overlap & more effective compression, because the intake valve closes earlier
114681.jpg

114681q.jpg

wider LSA, less overlap & less effective compression, because the intake valve closes later



USING THE .050 LIFT figures, notice that the tighter LSA (LOBE SEPARATION ANGLE)cam CRANES 110921 has the intake close at 45 degrees ABDC while the wider lsa CRANES 114681closes the valves at 50.0 ABDC (the wider LSA results in the valve closing 5 degrees later on the pistons compression stroke, effectively reducing the effective compression ratio
 
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budget cams, if your just trying to get basic transportation up and running theres some basic cam designs that have been around for decades that are an option.
yes youll need to research what fits your application


http://www.competitionproducts.com/Elgin-Chev-SB-Hydraulic-Flat-Tappet-Kits/products/2119/

http://www.competitionracingsupply.com/item--Erson-Cams--ERS110032---SBC-Hydraulic-Flat-Tappet-Cam-&-Lifter-Kit--cam_lifter_kit_chevy_chevrolet_small_block_hydraulic_flat_tappet_110032.html

http://www.jegs.com/i/JEGS/555/2001...9&cadevice=c&gclid=CMHHya6m08YCFQkIaQodnlEI6A

http://www.summitracing.com/search/...?SortBy=Default&SortOrder=Default&mbid=802512

http://www.enginepartswarehouse.net/store.php?catId=327

http://www.northernautoparts.com/ProductDetail.cfm?ProductId=3322

http://www.summitracing.com/search/product-line/summit-racing-cam-and-lifter-kits

http://www.gmpartsdirect.com/performance_parts/store/catalog/Category.jhtmlCATID=826.html

https://www.karlperformance.com/c/Solid-Lifter-Race-Camshafts/2439
keep in mind as always mandated proper clearances,
& checking valve train geometry, having proper valve spring load rates,
and having abundant lubrication flow rates is critical to proper durable function
and yes there's tips in the video that help you make good choices

remember the LSA ( lobe
separation angle) (ground in can't be changed on single cam engines)
and LCA can be advanced or retarded and will only be the same., as the LSA if the cams installed at split overlap or strait up

related links
0607phr_11_z+camshaft_basics+lobe_centerline_angle_determination_chart.jpg


LiftCurveAread.gif

volumetric.gif


pistonposition2a.jpg


heres a very useful link
yes THE VALVE SIZE VS THE CYLINDERS DISPLACEMENT MATTERS< ESPECIALLY IN THE CAM AND HEADERS DESIGN SELECTED

images


WPCMPv3h.jpg


images
 
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You know something from Todays DC C4 Tech I don't Grumpy.
I Didn't have time to research all on that engine build there.

My Olds 425 will idle 500-750 Rpm in gear and run on 87-91 octane Pee water gas.
Rely upon Good R/S ratio & 3.975" -- 3-15/16" crank stroke with 6 degree valve inclination heads.

T/A Is full Race.
 
Hey all. I have a 75 Chevelle with a stock GM 350 crate truck motor in with about 1k miles on it. I want to install a new cam in the motor but not sure what size to go with . Its primarly a street car so I dont want to go too big. Id like to go with the stock converter and springs if possible. My friend recommended a 410 ext lift but that seems too small. Whats the max I can go before I have to start changing springs and converter. Thanks!



https://www.summitracing.com/parts/crn-114132

as a rather well document boost in performance
usually at least 20 hp,
on most rather stock basic sbc engines, even stock automatic transmissions and stock converter stall speeds,
and one that works with power brakes and rarely causes any issues,
this crane cam is one Ive used frequently in many basically stock engines.
now obviously you need to install it correctly and carefully check clearances in the valve train, piston to valve clearance, etc.

why not call crane tech dept, and ask their advice?
I would NOT consider anything much larger, in lift or duration.
crane (386)310-4875
 
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a couple related videos worth watching





 
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Thank you Grumpy. I will forward this to my grandson and give him an idea of the kind of stuff makes a difference.
 
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