Looking for some Heads/cam basics
11-27-2001, 02:04 PM
#1
Looking for some Heads/cam basics Hey guys (and girls). I want to start off by saying I have learned more in my few days here than I have in months on "other" boards.
I am looking for some Camshaft Basics. I would like this for two reasons.
1) I am trying to learn about this stuff myself.
2) I would like to have something nice to add to the tech section of sffba.com.
I am looking for things like:
What is lift/duration/lsa? What do increases/decreases in each acomplish?
What makes a good boost cam? nitrous? N/A?
What is the different types of cams (Solid roller, hydraulic, etc), and the differences between them? What makes one better for a certain application than another?
What is Split duration?
What determines if a cam is too big for a motor?
Stuff like that......
If I can find a nicely written document, I will post it on the site, with the author of course getting much credit. <img src="images/icons/smile.gif" border="0">
Thanks for the help folks!!!
- Matt
I am looking for some Camshaft Basics. I would like this for two reasons.
1) I am trying to learn about this stuff myself.
2) I would like to have something nice to add to the tech section of sffba.com.
I am looking for things like:
What is lift/duration/lsa? What do increases/decreases in each acomplish?
What makes a good boost cam? nitrous? N/A?
What is the different types of cams (Solid roller, hydraulic, etc), and the differences between them? What makes one better for a certain application than another?
What is Split duration?
What determines if a cam is too big for a motor?
Stuff like that......
If I can find a nicely written document, I will post it on the site, with the author of course getting much credit. <img src="images/icons/smile.gif" border="0">
Thanks for the help folks!!!
- Matt
11-27-2001, 02:08 PM
#2
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Re: Looking for some Heads/cam basics If you go to
http://www.speeddemonmotorsports.com/
and click on "Tech" there are a couple of articles
there I have written. The camshafts one should talk some about what you are looking for.
Chris
http://www.speeddemonmotorsports.com/
and click on "Tech" there are a couple of articles
there I have written. The camshafts one should talk some about what you are looking for.
Chris
11-27-2001, 02:42 PM
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Re: Looking for some Heads/cam basics Heres some easy answeres.
Split Duration: different numbers on the intake and exhaust side of the cam profile, i.e. 226/234.
Single Duration: same specs on int. and exh., i.e. 221/221
Ususally the bigger the duration, the greater the capacity to make big power. But the bigger dur. cams are harder to make idle and tune, also. Lift adds power of course, but with the LS1 and lack of good spring alternatives, lift numbers are limited by spring choice...and trying not to bounce a valve off a piston (although duration plays a big part in clearance as well).
a turbo cam is a mystery to me, but for a blower, a wide LSA (114 and up) and greater numbers on the exhaust side of lift and duration are beneficial. For n2o i still think tighter LSA (112 and lower) is better for cylinder pressure, but as i stated before this may be moot at our power level. I mean at 100-150hp a wider lsa would probably give more power but may stress the engine a bit more. 200 and up, the lower the better with the lsa/cylinder pressure, as the stress would outweigh the hp gain with the larger lsa. Heres a quote from James at TNT:
[quote]I would go with a cam that favors the exhaust duration 10 degrees @.050 and .010-.015 on the exhaust. 112 is a good lsa for spray. I would have to see your flow numbers at the various lifts to help more but as long as you get somthing in there that has the same amount of lift as your heads peak flow you will be good. also remember that what we are trying to do is fill the cylinder with as much spray as possible so you will want a cam that pops the valve open at just the right time so your air speed is at its peak. Th e trick is to have it aggressive enough but not overly aggressive..The later will eat valve springs.<hr></blockquote>
Solid roller set-ups have solid lifers and need MUCH better valvetrains (double springs, shaft-mounted rockers, etc.). They are noisier and need some adjustment (or at lest checking) every 6000-8000 miles, but comparitively you can run bigger numbers (larger duration, tigher LSA) with less driveaility problems. We have Hyd. cams in our cars now, so the cost up upgrading is less.
Those are really simple answers to seemingly complicated questions.
Ryan
Split Duration: different numbers on the intake and exhaust side of the cam profile, i.e. 226/234.
Single Duration: same specs on int. and exh., i.e. 221/221
Ususally the bigger the duration, the greater the capacity to make big power. But the bigger dur. cams are harder to make idle and tune, also. Lift adds power of course, but with the LS1 and lack of good spring alternatives, lift numbers are limited by spring choice...and trying not to bounce a valve off a piston (although duration plays a big part in clearance as well).
a turbo cam is a mystery to me, but for a blower, a wide LSA (114 and up) and greater numbers on the exhaust side of lift and duration are beneficial. For n2o i still think tighter LSA (112 and lower) is better for cylinder pressure, but as i stated before this may be moot at our power level. I mean at 100-150hp a wider lsa would probably give more power but may stress the engine a bit more. 200 and up, the lower the better with the lsa/cylinder pressure, as the stress would outweigh the hp gain with the larger lsa. Heres a quote from James at TNT:
[quote]I would go with a cam that favors the exhaust duration 10 degrees @.050 and .010-.015 on the exhaust. 112 is a good lsa for spray. I would have to see your flow numbers at the various lifts to help more but as long as you get somthing in there that has the same amount of lift as your heads peak flow you will be good. also remember that what we are trying to do is fill the cylinder with as much spray as possible so you will want a cam that pops the valve open at just the right time so your air speed is at its peak. Th e trick is to have it aggressive enough but not overly aggressive..The later will eat valve springs.<hr></blockquote>
Solid roller set-ups have solid lifers and need MUCH better valvetrains (double springs, shaft-mounted rockers, etc.). They are noisier and need some adjustment (or at lest checking) every 6000-8000 miles, but comparitively you can run bigger numbers (larger duration, tigher LSA) with less driveaility problems. We have Hyd. cams in our cars now, so the cost up upgrading is less.
Those are really simple answers to seemingly complicated questions.
Ryan
11-27-2001, 02:58 PM
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Re: Looking for some Heads/cam basics I scanned in a good article a long time ago..might want to print em out.
http://www.austin-f-body.org/articles/cam01.jpg
http://www.austin-f-body.org/articles/cam02.jpg
http://www.austin-f-body.org/articles/cam03.jpg
http://www.austin-f-body.org/articles/cam04.jpg
http://www.austin-f-body.org/articles/cam05.jpg
http://www.austin-f-body.org/articles/cam06.jpg
http://www.austin-f-body.org/articles/cam01.jpg
http://www.austin-f-body.org/articles/cam02.jpg
http://www.austin-f-body.org/articles/cam03.jpg
http://www.austin-f-body.org/articles/cam04.jpg
http://www.austin-f-body.org/articles/cam05.jpg
http://www.austin-f-body.org/articles/cam06.jpg
11-27-2001, 03:12 PM
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Re: Looking for some Heads/cam basics [quote]Originally posted by Trans Am WS6 420:
Hey guys (and girls). I want to start off by saying I have learned more in my few days here than I have in months on "other" boards.
<hr></blockquote>
I couldnt agree with you more. <img src="images/icons/smile.gif" border="0"> This site is exellent. It is all the things an LS1"tech" site should be, minus the bullcrap found on other boards. I hope it stays that way too. <img src="images/icons/smile.gif" border="0">
Hey guys (and girls). I want to start off by saying I have learned more in my few days here than I have in months on "other" boards.
<hr></blockquote>
I couldnt agree with you more. <img src="images/icons/smile.gif" border="0"> This site is exellent. It is all the things an LS1"tech" site should be, minus the bullcrap found on other boards. I hope it stays that way too. <img src="images/icons/smile.gif" border="0">
11-27-2001, 03:13 PM
#7
TECH Enthusiast
Re: Looking for some Heads/cam basics 