110 or 112 lsa
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
No body said anything about altering the LSA.
I was simply stating that most "street cams" have four degrees advance built in / ground in. This advance in valve timing gives the car that off-idle, gobs of torque that most customers want on the street, but few want on the full time drag strip.
So when you dial-in a cam a additional four degrees by moving the crank sprocket to a different slot, you more than likely now have eight degrees advance.
If you want a screamer that seldom runs below 5,000, then you retard the cam or set it up at zero. The power band is then moved from 5,000 - 8,000 for example.
I was simply stating that most "street cams" have four degrees advance built in / ground in. This advance in valve timing gives the car that off-idle, gobs of torque that most customers want on the street, but few want on the full time drag strip.
So when you dial-in a cam a additional four degrees by moving the crank sprocket to a different slot, you more than likely now have eight degrees advance.
If you want a screamer that seldom runs below 5,000, then you retard the cam or set it up at zero. The power band is then moved from 5,000 - 8,000 for example.
Thread Starter
Le Mans Master
Joined: Oct 2010
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From: melbourne florida
2023 C3 of the Year Finalist - Modified
FWIW
Manufacturer grinds CenterLInes where it wants and user can advance or retard install where he wants.
Manufacturer grinds Centerlines where it wants and that determines how much separation angle LSA is between the two.
User cannot change LSA (or overlap); It's ground in. If you can change your LSA, you must have one helluva grip to match that big chip.
Manufacturer grinds CenterLInes where it wants and user can advance or retard install where he wants.
Manufacturer grinds Centerlines where it wants and that determines how much separation angle LSA is between the two.
User cannot change LSA (or overlap); It's ground in. If you can change your LSA, you must have one helluva grip to match that big chip.
Thread Starter
Le Mans Master
Joined: Oct 2010
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From: melbourne florida
2023 C3 of the Year Finalist - Modified
He knows exactly what I'm looking for . I'm going to the 110 lsa cam he speced out and if my headlights are sluggish I'll address that. Thanks everyone for your input. I hope nobody is upset with me about anything. I've had some real stress lately and sometimes I need to read things a couple of times.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
With a little research, all I could find was that the L82 cam had a centerline of 110*. And a lobe separation angle of 114*.
I could be wrong but I believe that means four degrees of advance GM built-in from stock. (Take the LSA and subtract cntr line, 114 minus 110= 4*)
So, the stock 4* + your added 4* = 8* total.
But hey, its your car. Do what you want. Lots of people have done that. The RPM power band drops off early is all.
I could be wrong but I believe that means four degrees of advance GM built-in from stock. (Take the LSA and subtract cntr line, 114 minus 110= 4*)
So, the stock 4* + your added 4* = 8* total.
But hey, its your car. Do what you want. Lots of people have done that. The RPM power band drops off early is all.
Was Not me who suggested yours is advanced 8* ... was someone else
I don't question why or even if you advanced yours. Some 20 years ago, I chose a Crane-Wolverine-Blue Racer Clone of same cam for a mild budget 383 (388) I built. It did a good job and it was cheap.
Back then, maybe same company was supplying same cam to GMPP as a 962 dunno. You posed a valid question (110 or 112)? My best guess is you'll like a 110 LSA ... maybe even 108.
& as for that other thread... I ain't never been skeered of no dang intake gasket
Le Mans Master
Joined: Apr 2006
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I had a 73 with a 454 that I bought new , by 1974 i had a solid cam in it with 310/320 adv. Duration 265 at .050 the lsa was 108 and it had 90 degrees of overlap. The brakes worked with no problems and so did both headlights. Now a 454 is a bit more of a vacuum pull then a 350 and the headlight system was basically new. But the cam I just described is a monster compaired to any 280 degree seat to seat cam. You worring about 110 or 112 lsa a waste of your time you can do 108 if you like for some more overlap.
Team Owner
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Safety Car
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From: New York
A wide LSA reduces valve overlap, softens the idle and improves overall drivability–especially on the street where performance engines benefit from 112 to 114 LSA. ... Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures.
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Generally speaking yes, but as said with todays profiles you can have your cake and eat it too...to an extent.
Gone are the days where you have to "order" a wide lsa to have more vacuum.
Worst case he gets a cheap canister big deal...or vacuum pump.
82 deg overlap a simple reservoir gives me factory brake feel
Gone are the days where you have to "order" a wide lsa to have more vacuum.
Worst case he gets a cheap canister big deal...or vacuum pump.
82 deg overlap a simple reservoir gives me factory brake feel
Dr. Detroit
Joined: Mar 2012
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From: New Braunfels Texas
Thats fake news LMAO , , LSA plays a roll and to say it does not is silly.
A wide LSA reduces valve overlap, softens the idle and improves overall drivability–especially on the street where performance engines benefit from 112 to 114 LSA. ... Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures.
A wide LSA reduces valve overlap, softens the idle and improves overall drivability–especially on the street where performance engines benefit from 112 to 114 LSA. ... Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures.
Back to your regularly scheduled programming.
Jebby
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
GM did not retard the cam for emissions. I already showed you the L82 specs: LSA is 114, minus the centerline of 110 equals 4* of advance.
That four degrees is very, very common for street grind cams.
So. If you install your cam "straight-up" as they call it, or right at zero degrees, you have four degrees advance already built in. End of that story.
But wait!
Then, some people set the crank sprocket to the slot that indicates four additional degrees advance.
Last I looked four and four are eight degrees.
That four degrees is very, very common for street grind cams.
So. If you install your cam "straight-up" as they call it, or right at zero degrees, you have four degrees advance already built in. End of that story.
But wait!
Then, some people set the crank sprocket to the slot that indicates four additional degrees advance.
Last I looked four and four are eight degrees.
Last edited by HeadsU.P.; Jan 16, 2020 at 04:45 PM.
Thread Starter
Le Mans Master
Joined: Oct 2010
Posts: 6,903
Likes: 834
From: melbourne florida
2023 C3 of the Year Finalist - Modified
GM did not retard the cam for emissions. I already showed you the L82 specs: LSA is 114, minus the centerline of 110 equals 4* of advance.
That four degrees is very, very common for street grind cams.
So. If you install your cam "straight-up" as they call it, or right at zero degrees, you have four degrees advance already built in. End of that story.
But wait!
Then, some people set the crank sprocket to the slot that indicates four additional degrees advance.
Last I looked four and four are eight degrees.
That four degrees is very, very common for street grind cams.
So. If you install your cam "straight-up" as they call it, or right at zero degrees, you have four degrees advance already built in. End of that story.
But wait!
Then, some people set the crank sprocket to the slot that indicates four additional degrees advance.
Last I looked four and four are eight degrees.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
FWIW as a comparison
OE iron Vortec L31 350ci LSA = 111* (FYI: that OE cam has Plenty of vacuum for brakes).
Specs for Melling replacement cam (M1320) for above is .414/.428, 191*/194*, 261*/263*, ICL 106*, ECL 116*, LSA 111*
for Melling replacement cam (22210) for OEM 3896962
.450/.460 224*/224*, 291*/287*, ICL 114*, ECL 114*, LSA 114*
IO -3* BTC, IC 47* ABC
XO 46* BBC, XC -2* ABC
**Melling cat 010118-1 c2018
OE iron Vortec L31 350ci LSA = 111* (FYI: that OE cam has Plenty of vacuum for brakes).
Specs for Melling replacement cam (M1320) for above is .414/.428, 191*/194*, 261*/263*, ICL 106*, ECL 116*, LSA 111*
for Melling replacement cam (22210) for OEM 3896962
.450/.460 224*/224*, 291*/287*, ICL 114*, ECL 114*, LSA 114*
IO -3* BTC, IC 47* ABC
XO 46* BBC, XC -2* ABC
**Melling cat 010118-1 c2018
Specs for Melling replacement cam (M1320) for above is .414/.428, 191*/194*, 261*/263*, ICL 106*, ECL 116*, LSA 111*
LSA 111* - ICL 106* = 5* (cam ground with Five Degrees Advance)
<addendum in red>
Specs for Melling replacement cam (22210) for OEM 3896962 aka L82 cam
.450/.460 224*/224*, 291*/287*, ICL 114*, ECL 114*, LSA 114*
LSA 114* - ICL 114* = 0* (cam ground with Zero Degrees Advance)
Last edited by jackson; Jan 17, 2020 at 04:48 PM.
Le Mans Master
Joined: Feb 1999
Posts: 8,351
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From: Tampa Bay FL
talking to my cam grinder about a replacement for my L-82 cam. he thinks it may be safer from the engine vacum aspect to do a 112 lsa to play nice with power brakes and headlights. were right at 10-1 compression were talking 280 ish duration and .500 lift. his thought is with the 1.6 rockers i have with 112 lsa i won't gain much but 110 would allow a bit more horsepower. any thoughts? please none of this roller cam is better stuff. these guys grind high quality cams that I've used several times in over 40 years. otherwise i will stay with what i have. thanks for any intelligent input.
Remember, everything else needs to be in top shape or you will replace a cam/lifters and still be unhappy. Initial timing, spark advance curve, carb jetting, cylinder head flow/valve sizes, intake, exhaust, healthy vacuum system (no leaks). It all matters.
Summary of my setup is in my signature. Achieved from 1997 thru 2014. I stopped after I got as much as I can out of the current .020 over 350 without adding (more) lift and cubic inches (next step would be a 383 in my opinion). Just not wanting to open the wallet more (at least in engine).
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
There is other factors involved in determining the vacuum an engine makes, its not ALL about LSA.... Duration numbers, valve opening/closing events, overlap etc all affect vacuum production. I have cams with 110 LSAs that make 12 hg vacuum.... and I have a LS cam with a 113 LSA that makes 9 hg vacuum.... I had a custom "blower cam" in my C5Z that had 115 LSA, it made 7.5 hg of vacuum and would not run power brakes... You need to look at the big picture here. Get a cam that is going to meet your goals and have it spec'd as a whole... don't get target fixated on one spec when there is much more at play here.
If in doubt, contact a pro...
FWIW, I have an XE 268 in a 9.5-1 comp 357" and its on a 110lsa and makes 12 hg of vacuum at 800 rpms....Power brakes work great.
If in doubt, contact a pro...
FWIW, I have an XE 268 in a 9.5-1 comp 357" and its on a 110lsa and makes 12 hg of vacuum at 800 rpms....Power brakes work great.
Last edited by ajrothm; Jan 17, 2020 at 08:04 PM.