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camshaft profile how do you figure
https://slantsix.org/forum/viewtopic.php?t=48348		 Page 1 of 1
Author:  USAJon [ Sat Mar 31, 2012 7:07 pm ]
Post subject:  camshaft profile how do you figure
wondering how is the best way to find a camshaft profile for your build?
Author:  ceej [ Sat Mar 31, 2012 7:20 pm ]
Post subject: 
That's very subjective.

Depends on what your trying to do with the vehicle, how your feeding it, and what expectations you have for longevity.

At what engine speed do you want the engine to work? Any adders? Bore size? Stroke? Hydrualic or Mechanical? Lot's of stuff to consider.

The profile has to match every other part in the build, especially when working with a relatively small cubic inch engine. Mismatches create problems.

It all adds into the equation.

CJ
Author:  USAJon [ Sat Mar 31, 2012 7:45 pm ]
Post subject: 
port/polish head/large valves/10.5 comp/.30 over bore 225 engine/mech camshaft/lifers/track use but some street/4 barrel carb/intake/3800 stall..5.38 rear /30inch tires/gutted 1968 dart.

fun drive not a daily one.
Author:  slantzilla [ Sat Mar 31, 2012 8:01 pm ]
Post subject: 
I would go with at least a .550" lift and 250* .050" duration at least.

If some of those Reed cams Howard Davis had for sale are still available you wouldn't do too badly with one of them.
Author:  ceej [ Sun Apr 01, 2012 1:04 am ]
Post subject: 
Holy Shnykies! I wouldn't get to carrried away with lift. Did you know Madmax is well uinder .500 Lift? Contact MIke Jeffery about cam suggestions.

All your going to net is higher wear with .5x llift. What is your seat angle? If your running NA, stick with 30° With Boost, go 45°.

Gross at 500. Keep it at or below .470 after deucting lash. Youve got lots of rpm, so pump up the duration.

I take it your racing 1/8th. Otherwise your gears look terrible! :lol:


CJ
Author:  slantzilla [ Sun Apr 01, 2012 4:05 am ]
Post subject: 
Quote:
Did you know Madmax is well uinder .500 Lift?
Somebody is blowing smoke up your patootie. :roll:

Mark has less lift and duration than my old 300 Clifford, but not that much less. :lol:
Author:  USAJon [ Sun Apr 01, 2012 5:40 am ]
Post subject: 
I take it your racing 1/8th. Otherwise your gears look terrible! :lol:


CJ[/quote]

1/4 mile/looking @ a convert to 2004R OD when the gears go in.
do have rear/gears sitting in bacement.

possibally? end o'season T5 convert

should have funding/ work will be outside so that will be fun....
Author:  CNC-Dude [ Sun Apr 01, 2012 12:12 pm ]
Post subject: 
Even for 1/8 mile that gear is too steep unless you have a very, very heavy car. You want the engine to push the car down the track, not the gear. Your valve lift should maximize and match your port flow to get the most out of. So if you have access to a flowbench that could help you to start putting some specs together to being profiling the cam for your needs.
Author:  ceej [ Sun Apr 01, 2012 1:10 pm ]
Post subject: 
Quote:
Somebody is blowing smoke up your patootie. :roll:
That could very well be! :lol:
Author:  slantzilla [ Sun Apr 01, 2012 3:49 pm ]
Post subject: 
Quote:
Quote:
Somebody is blowing smoke up your patootie. :roll:
That could very well be! :lol:
Welllllll, it is April Fool's Day. :lol: :lol: :lol: :lol:

But yeah, somebody fed you a line. :shock:
Author:  ceej [ Sun Apr 01, 2012 4:47 pm ]
Post subject: 
Hey Mark! Did you ever get your cam card back?

Mark told me it was under .500" net lift on one of our phone calls. It could very well be he was talking about something else.

CJ
Author:  DadTruck [ Sun Apr 01, 2012 6:35 pm ]
Post subject: 
to make good choices on a cam profile, 1st thing you want to do is become comfortable with the terminology.

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

may be as good as it gets.

once you think you have a handle on :LCA-ICL-duration-lift,, start googling David Vizard and cam profiles...If you are like me you will then go back and read the cam expert article about three more times. Eventually it all becomes knowledge.
here is one of those articles that will stretch your understanding.
http://www.hotrod.com/techarticles/cam_ ... ngle_tech/

between that and a few posts here, I got comfortable enough to spec out my own cam, got it ground and its installed in a block,, may actually get it running late this spring. :D if it runs great, and I think it will, I'll have accumulated the knowledge on why it performes,, but it may be a turd,, if so. at least I will know why I spec'd out the cam, and should know what to correct from there..
Author:  sandy in BC [ Mon Apr 02, 2012 6:30 am ]
Post subject: 
Good cam choices start with an understanding of Dynamic Compression Ratios.....or DCR.
Author:  Doc [ Mon Apr 02, 2012 9:04 am ]
Post subject: 
I agree... run the DCR calculations for the static compression and find the suggested Intake Closing point, and get a cam that supports that IC point.

For your 10.5 CR, looks like an IC at 70 ABDC (pump gas) to 62 (race fuel) is about where you want to end-up. (8.0 to 8.5 DCR range)
DD
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