what do lsa#'s indicate on cam?
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 7,727
Likes: 7
From: Twilight zone
St. Jude Donor '05-'06
what do lsa#'s indicate on cam?
What are these?...if two identical # grinds...except one has a 112 and one has say a 114...whats the dif?
Also, I have seen +1-+2 after....whats that? I mean how does that change and what?
I am in Emissions tight ca., so I need to know what numbers to keep away from here,so...any advise would be appreciated
thanx fellas!
Also, I have seen +1-+2 after....whats that? I mean how does that change and what?
I am in Emissions tight ca., so I need to know what numbers to keep away from here,so...any advise would be appreciated
thanx fellas!
Last edited by flynbya2; Mar 26, 2005 at 07:20 PM. Reason: gramma..lol
Burning Brakes
Joined: Sep 2002
Posts: 1,117
Likes: 1
From: Cedar Falls Iowa
LSA stands for Lobe Seperation Angle. Usually shown as 114 degrees or 112 degrees. Its the number of degrees between the Intake center line and Exhaust center line. VALVE GEOMETRY TALK.
At least thats what I thought, could always be wrong?
My .02
At least thats what I thought, could always be wrong?
My .02
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 7,727
Likes: 7
From: Twilight zone
St. Jude Donor '05-'06
ok..thanx
that sounds good..and right
now, what does that mean "real world"..what does a higher (I guess 114?) lsa mean comparing to a lower one?
what does the difference do?..anyone? OR is it of little consequence??
thanx
that sounds good..and right
now, what does that mean "real world"..what does a higher (I guess 114?) lsa mean comparing to a lower one?
what does the difference do?..anyone? OR is it of little consequence??
thanx
Last edited by flynbya2; Mar 26, 2005 at 07:23 PM. Reason: last question
Safety Car
Joined: May 2000
Posts: 4,827
Likes: 352
From: Albuquerque NM
A 114 LSA cam will idle better and pass smog easier than a 112. The 112 will have more mid range torque but they should be simular on the top end.
FWIW I pass smog with the 5.3 heads, shaved to give 11.4 CR, and with a mild cam, 218/218 114LSA and .558" lift. I've read of folks passing smog with a 224/224 114 LSA .561" cam, bigger would be pushing it.
FWIW I pass smog with the 5.3 heads, shaved to give 11.4 CR, and with a mild cam, 218/218 114LSA and .558" lift. I've read of folks passing smog with a 224/224 114 LSA .561" cam, bigger would be pushing it.
Last edited by 6Speeder; Mar 27, 2005 at 12:49 PM.
Drifting
Joined: May 2003
Posts: 1,715
Likes: 1
From: cAshburn VA
You can also do a search on "degree-ing a cam" and see exactly what the difference is.
Generally the higher the LSA the smoother the idle, however I have heard that big cams with higher LSAs can have problem with valve clearence.
When I did my cam it was a 112 +4, which makes my target intake centerline (IC) 108 degrees (on a 360 wheel). So the the degree the cam rotates from, if I remember right (and I may not), when the intake valve starts to open until it closes, is 108 degrees. At dot-dot (cam to crank) timing my cam came in at 105-ish, using the adjustable double roller timing set I was able to "dial-in" the cam to 108.5 degrees. Money!
If you ever have any doubts, give CompCams help line a call, those guys are great.
Generally the higher the LSA the smoother the idle, however I have heard that big cams with higher LSAs can have problem with valve clearence.
When I did my cam it was a 112 +4, which makes my target intake centerline (IC) 108 degrees (on a 360 wheel). So the the degree the cam rotates from, if I remember right (and I may not), when the intake valve starts to open until it closes, is 108 degrees. At dot-dot (cam to crank) timing my cam came in at 105-ish, using the adjustable double roller timing set I was able to "dial-in" the cam to 108.5 degrees. Money!
If you ever have any doubts, give CompCams help line a call, those guys are great.
