The formula for figuring valve events. ..would that be helpful
Thread Starter
Joined: Oct 2003
Posts: 1,386
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From: Tri-Cities, TN
The formula for figuring valve events. ..would that be helpful to anyone on the board. As long as you have duration and centerline you can calculate opening and closing of the valves. I was asked for this on another board after the fella called several cam companies and no one new how?
Chris
Chris
6600 rpm clutch dump of death Administrator
Joined: Dec 2001
Posts: 4,983
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From: Texas
Chris knows how, trust me on that. I think his point was that he can provide it for anyone who needs it. I put it in my Excel spreadsheet so you can plug an go. The actual formulas are in the cam thread.
https://ls1tech.com/forums/showthrea...aft+discussion
The spreadsheet is here.
http://users3.ev1.net/~black_ops/cam...calculator.xls
https://ls1tech.com/forums/showthrea...aft+discussion
The spreadsheet is here.
http://users3.ev1.net/~black_ops/cam...calculator.xls
Thread Starter
Joined: Oct 2003
Posts: 1,386
Likes: 39
From: Tri-Cities, TN
J-rod, that works, now I don't have to do it long hand in my mind. It was helpful on another board and I did not realize you had done this.
We got the prints on the "07 Gen 3. It will be pretty cool.
Chris
We got the prints on the "07 Gen 3. It will be pretty cool.
Chris
6600 rpm clutch dump of death Administrator
Joined: Dec 2001
Posts: 4,983
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From: Texas
Originally Posted by 99 Black Bird T/A
Chris, I would be greatful for the formula.
thanks
wade
thanks
wade
From page 1 of the thread...
How to calculate VE's given duration, LSA, & ICL:
Example cam 230/236 112LSA 108ICL
IVO = ((intake duration/2)-ICL)
Ex: ((230/2)-108)= 7 BTDC (negatives indicate ATDC)
IVC = ((-IVO) + intake duration - 180)
Ex: ((-7) + 230 - 180) = 43 ABDC
ECL = ((2 * LSA) - ICL)
Ex: ((2 * 112) - 108) = 116
EVC = ((exhaust duration / 2)- ECL)
Ex: ((236 / 2) - 116) = 2 ATDC (negative indicates BTDC)
EVO = ((-EVC) + exhaust duration - 180)
Ex: ((-2) +236 - 180) = 54 BBDC
Overlap = ((intake duration + exhaust duration)/2) - (2 * LSA)
Ex: ((230+236)/2) - (2 * 112) = 9
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Verdad Gallardo Thanks for the formulas I missed the link when I glanced at the thread.
Question about overlap.
What's the most overlap you have have and still pass emissions with a sniffer?
~1-2 degrees?
Question about overlap.
What's the most overlap you have have and still pass emissions with a sniffer?
~1-2 degrees?
wayy more than 1-2 degrees has blow clean. depends on more than just cam, tune, how effecient everyhtign in the motor is, clean burn. Cam with some overlap 230/230 for ex. in a huge motor wont be much cam at all
Originally Posted by Revelation222
Quick question..how do you establish the ICL? It is different than the LSA? J-rod, someone... help 
www.compcams.com/Technical/TimingTutorial/
TECH Enthusiast
Joined: Jun 2003
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From: So Cal
Originally Posted by wrencher
This might help;
www.compcams.com/Technical/TimingTutorial/
www.compcams.com/Technical/TimingTutorial/
6600 rpm clutch dump of death Administrator
Joined: Dec 2001
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From: Texas
Originally Posted by Revelation222
Well that gave me a headache. lol thanks. So, if you have a cam with a lsa of 114 with no advance ground in, the ICL will also be 114? But if it were ground with 4 degrees of advance the ICL would be 110? Is this correct? Assuming I got all that...you can also change the ICL by installing the cam advanced or retarded...for instance with the 114LSA ground straight up but then installed 4 degrees advanced would give us our 110ICL? Hope I got it this time.
ICL = LSA-(Advance)
So, if you have a 114LSA +0, you get a 114ICL 114-(0)=114
Most cams coming from the big name shops grind 4 degrees of advance into the cam, so you get 114-(+4)=110ICL
If the cam was retarded 4 degrees 114 -4, 114-(-4)= 118ICL.
ICL can be modified either from the manufacturer in how the cam is ground, or the end user can modify it by advancing or retarding the cam.
Thread Starter
Joined: Oct 2003
Posts: 1,386
Likes: 39
From: Tri-Cities, TN
Ok with all this math taken care of, what do these engines like?
Well, what they want is much different from whats going in them. . .their is still power to be found in these cars.
Chris
Well, what they want is much different from whats going in them. . .their is still power to be found in these cars.
Chris
I've been toying around w/ VE's using 93Pony's way of thinking then corresponding it to some of Comp's XE-R lobes. Maybe I can put something together, throw it in, and see if it works.
TECH Enthusiast
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From: So Cal
Originally Posted by J-Rod
ICL = LSA-(Advance)
So, if you have a 114LSA +0, you get a 114ICL 114-(0)=114
Most cams coming from the big name shops grind 4 degrees of advance into the cam, so you get 114-(+4)=110ICL
If the cam was retarded 4 degrees 114 -4, 114-(-4)= 118ICL.
ICL can be modified either from the manufacturer in how the cam is ground, or the end user can modify it by advancing or retarding the cam.
So, if you have a 114LSA +0, you get a 114ICL 114-(0)=114
Most cams coming from the big name shops grind 4 degrees of advance into the cam, so you get 114-(+4)=110ICL
If the cam was retarded 4 degrees 114 -4, 114-(-4)= 118ICL.
ICL can be modified either from the manufacturer in how the cam is ground, or the end user can modify it by advancing or retarding the cam.
