Help picking a cam

Grind No./Type: 264-MEGA HYDRAULIC FT**
Application: Tremendous torque & good mid-range power.
9-10.5:1 compr., good idle, stock converter.
3.23-3.70 axle ratio. Up to 625 CFM Carb.
RPM-Range: 2000-5800
Valve Lift Int/Ext: .450/.450 (1.5), .480/.480 (1.6)
Valve Lash Hot Int/Ext: .000/.000
ADV Duration Int/Ext: 264/264
.050 Duration Int/Ext: 214/214
Lobe Center: 108 108° LSA /108° ICL = straight up

Seat-to-seat timing (Wallace) (IN .007”, EX .010”) ISKY
IVO is 24.0 ° BTDC (- indicates ATDC)
IVC is 60.0 ° ABDC
EVO is 60.0 ° BBDC
EVC is 24.0 ° ATDC (- indicates BTDC)
Overlap is 48 °

.050” Valve Events – IN Opens 1 ATDC IN Closes 35 ABDC
EX Opens 35 BBDC EX Closes 1 BTDC

The Lunati 60102 looks good on paper. Let's see what Grumpy says.
You must realize that cam descriptions vary. What one company might call a good idle,
another might call fair. Remember, they are all trying to outsell each other.
The same camshaft will also behave differently in a small CI engine than in a larger one.

Have you looked at this one?
http://www.lunatipower.com/Product.aspx?id=3855&gid=110
 
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Oh yeah, I just remembered...... your stock rockers might not work at these valve lifts
because the slot for the stud in the rocker might not be long enough and there could be
interference between the rocker and the stud at full valve lift.
It's another quick way to kill a camshaft.

Grumpy is not a fan of them, but I like their simplicity - the CompCams roller tip rockers.
They have a longer slot and a roller tip. What I like - no needle bearings to fail.
http://www.compcams.com/information/Products/RockerArms/MagnumRoller.asp
DO NOT BUY THE IMPORT COPIES!
 
No I haven't seem that cam yet. I do realize that cam companies are all trying to sell sell sell. I have however read allot of independent reveiws of the 60102 in combos with even less compression then me and people seem to love it. I also came across a forum where a guy with an identical setup to mine was recommended that cam by UDHarold.
 
I tried downloading that calculator and I could not get it to work. I was using a calculator off of an old post grumpy had made about DCR that I found on this forum. Those rockers are about halfway to full roller rockers maybe I should just get full rollers then.
 
4doorscooter said:
I have a new question. Some cam kits come with pushrods, how can they possibly know they are the correct length?
Click to expand...

They can't. That is more for the people who buy parts and slap them together without measuring anything.
Sometimes they get lucky, sometimes not. Engine builders actually measure. That's the difference.
With all of your good questions, you are smarter than those parts changers.

It's also that their supplied parts work probably 95% of the time.
I don't know about you, but I find myself in that other 5% category 95% of the time.
 
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keep in mind the cam lobe ramp acceleration and valve spring load rates.
as any decent mechanic will tell you, you need to finish a race to win it and having a car that constantly breaks parts won,t be fun, and gets darn expensive very rapidly
if your valve train won,t remain stable and under control consistently and handle the stress at the cams intended max rpm, (plus a bit more) your almost sure to have low durability, lots of valve train wear and parts breakage!
lets say your comparing two similar cam,s with listed specs
ones got 215 duration with .450 lift,
the others got 215 duration with 510 lift
Id bet 90% of the guys reading that figure.....hey I get more lift with the second cam, thats obviously going to improve air flow & potential power, so thats the route to take....WRONG!!!

with flat tappet cams, if you exceed a certain lobe acceleration angle you tend to develop valve control and wear issues rather rapidly , mostly because the valve spring load rate required to maintain lifter to cam lobe contact at higher rpm ranges, potentially causes extremely high contact pressures between the two moving surfaces.

SPEND $10 and get a calculator ,in this hobby its a darn useful tool

ticalcx1.jpg

http://www.walmart.com/ip/Texas-Instruments-TI-30X-IIS-Scientific-Calculator/1535939


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 .50 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.
ones got 215 duration with .450 lift,215/450=.47.7%
the others got 215 duration with 510 lift/215/500=43%

one factor I will mention is that each manufacturer tends to look at durability, ramp speeds and max lifter acceleration very differently, one reason I tend to prefer CRANE & CROWER is that they both company's in general realize the engine must finish the race to win and a busted valve train is a HUGE problem,they both realize, and design valve train components and cam lobes with DURABILITY and reliable valve control as top priority,s that are far more important than squeezing every possible potential HP from a cam lobe design at the expense of long term durability
http://garage.grumpysperformance.com/index.php?threads/cam-lobe-aceleration-rates.2627/#post-6777

http://garage.grumpysperformance.co...s-on-valve-spring-pressures.10268/#post-41364

http://garage.grumpysperformance.co...-rocker-ratio-help-your-combo.2632/#post-6790

http://garage.grumpysperformance.co...-calculators-and-basic-math.10705/#post-46737
 
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302 I appreciate the kind words I really am trying to do this the right way. And grumpy thanks for that formula that makes allot of sense to me. I also agree that valve train durability is something I want. That crane 114142 and mega 264 are still a top contender in my choices right now. In gonna play with that new formula and let you guys know what I've found!
 
Ok guys i took grumpy's formula and I ran the numbers here is what I found.

Lunati 60102 = 46.7%
mega 264 with 1.5 rockers=47.5% with 1.6 rockers= 44.5%
crane 1142 with 1.5 rockers=47.5% with 1.6 rockers=44.6%

So my takeaway from this is the Lunati cam is completely off the table, and both the Isky and Crane are spot on however they can not be run with 1.6 ratio rockers as this puts them farther below the 47.5% then the lunati is with very similar lift. what are you're thoughts guys?
 
you CAN RUN the 1.6:1 ROLLER rockers, on your cars engine ,, keep in mind its a rather generic formula, built on well known average results and covers factors your relatively low rpm crossfire engine will not generally push the limits on with the fairly mild duration, lower lift hydraulic flat tappet cam.
the formula is used to calculate the load rates that cause issues over time,
and roller rockers provide less effective friction.
stress is BOTH CUMULATIVE and TO A LARGE EXTENT RPM DEPENDENT, or at LEAST STRONGLY RELATED, what STRESS your valve train sees at 5000 rpm, is no where close to what it sees at 6000 rpm plus
P12CHARTS.jpg

 
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I am confused now :confused:. so the 47.5% is not set in stone its just a general guide is that correct? so really all of these cams are still valid options as they are all very close to that number? how about this if this was you're engine and you wanted a cam that gave good torque and mid range power what cam would you gentlemen choose?
 
Grumpy, correct me if I'm wrong, but the 47.5% rule is based on the rocker ratio of 1.5.
4doorscooter, think of it this way, it is about the camshaft's lobe profile (intensity) and lift vs .050" duration.
That rule is not concerned if you run higher ratio rockers, because that effects what happens the valve.
It is just a comparison formula to help compare different lobe profiles.
Adding a 1.6 rocker does not change the lift or shape of the lobe. Get it???

For cost savings, did you see the Elgin copy of that Crane cam?
 
so the 1.6 rocker is merely adding more lift but obviously has no affect on the profile of the lobe got it. I did see the crane copy but for some reason I have no idea why i just feel safer in buying the actual cam from the company. I know I could save cash and probably be fine its just peace of mind for me haha.
 
I notice a trend towards the Crane cam, it does seem like a good solid performer and I did run a crane cam in a 305 I had when I was in high school and it surprised me with its performance. So maybe I should go with what I have had success with in the past.
 
Go with what you know to be true.
You can read about other people's opinions, but you have to be happy with your decision in the end.

Opinions are like assholes - everyone has one - and they all stink!
 
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