I saw somewhere that the lift is .591/.591 but it did not list the duration? Anyone know?

 

this should go to the LS2/LS7 section

 

sorry about that, i'm so used to posting in the ls1/ls6 section. Anyone know?

 

LS7 427 cam specs: Dur. @ 0.050 211/230, lift 0.593 Int. - 0.588 Exh.

thats straight from crane cams

 

cool, thanks.

 

I was thinking about putting a LS7 cam in my LS2 engine I think it would be ok for a street & strip
cam I just wonder if the push rod length would change I would use the Manley Bee hive springs & titanium retainers also Manley push rods. I have a SSTB LS2 (auto trans) 4.10 rear. Good idea or not?

 

LS7 uses a different rocker ratio. (1.8:1 I believe) Is yours 1.7:1?

 

yea. must have to replace those valve springs ever 5k miles...

/sarcasm.

 

I will move it for you. No problem man.

 

I think the rocker ratio is different also the rockers on the LS7 heads are offset on intake & stright on the exhaust because of the head design on the LS7 heads also different ratio rockers. The cam should work in the LS2 with the stock or aftermarket rockers with a spring change & push rods. Like Manley
bee hives for no coil bind since the LS7 probably has taller springs to take a even larger cam. Since some guy's are using cams in the same range already in the LS2 I think that won't be a issue. I just need to see a dyno curve to see how the low end & mids are since it is a 7,000 rpm cam. As heavy as
the SSTB's are they may need a custom grind with big low rpm torque numbers also large mids in torque & HP. 4660 lbs. with jack spare & a full tank of gas. So track weight about 4400 lbs with a diet. The do make some 32lb. wheels 18" & 20" for a combo DR's on the back maybe save 20 lbs a wheel over stock. Any suggestions?

 

I have several stock LS7 cams I can sell. Email me if you're interested.
jason@Katechengines.com

 

I don't think that it is that good of an idea. The LS7 cam is optimized for the breathing characteristics of the LS7 heads. LS2 heads breath way differently than the ls7's. The split on the stock cam has way too much exhaust bias. You mentioned a custom cam, I def think that is the way to go for you since your application is not the norm. good luck.

 

I bet this cam would rock in an LS2 402 with L92 heads and an L76 intake. Hmmm....

-Geoff

 

whts the adv. duration?

 

can u please post the seat timing and other specs of the ls7 cam
also what are the price of the ls7 cams, are they takeoffs from project cars.
if u cannot post the specs of the cam, can u post the overlap with 1.8 rockers, thanks

 

Yeah because it made a whopping 445rwhp in a 427 WITH ls7 HEADS...rockin'

just playin'.

 

LS7 cam - 505 HP - 28 mpg

211 - intake duration @ .050

230 - exhaust duration @ .050

120 - LSA (lobe separation angle) camshaft degrees

120 - intake/exhaust lobe centerline straight up in crank degrees

123 - ILC (intake lobe centerline) factory installed @ 3 degrees retard

.591 - intake valve lift

.591 - exhaust valve lift

As opposed to a dual camshaft setup, a single cam's LSA will be fixed at birth, it cannot be altered. The ILC/ELC can be advanced or retarded with one affecting the other. Advancing the ILC, retards the ELC.......retarding the ILC, advances the ELC, but the 120 LSA relationship will never change or will the overlap.

The factory installs the LS7 in the 3 degree retarded position:

123 - ILC - (Intake Lobe Center)
117 - ELC - (Exhaust Lobe Center)
__________________________________________________ _____________________

Quick overlap calc:

Add the in/ex duration
Divide by 4
Subtract the LSA
Multiply by 2

Example:

211 + 230 = 441

441 / by 4 = 110.25

110.25 - 120 = -9.75

-9.75 x 2 = -19.5

Overlap = -19.5 degrees of negative overlap
__________________________________________________ ____________________

Wide SLA = low, zero or negative overlap for good gas milage and emmision control

Wide SLA = relatively early exhaust valve opening for restrictive exhaust systems

Wide SLA = relatively late intake valve closing for controlling dynamic pressure with 11:1 CR

Massive intake port flow capability allows relatively low 211 intake duration combined with .591 lift

Increased exhaust duration of 230, combined with early exhaust opening and .591 lift helps combat restrictive street exhaust system.
__________________________________________________ ____________________

LS7 Cam profile @ ILC/ELC 120 straight up - 211/230 duration

IO......... -14.5 atdc

IC......... 45.5 abdc

EO......... 55 bbdc

EC......... -5 btdc

Overlap = -19.5 and 120 LSA
__________________________________________________ ___________________

LS7 Cam profile @ ILC/ELC 123/117 - 3 degree retard - 211/230 duration

IO......... -17.5 atdc

IC......... 48.5 abdc

EO......... 52 bbdc

EC......... -2 btdc

Overlap = -19.5 and 120 LSA
__________________________________________________ __________________

Intake Timing calcs:

intake duration = 211

divide by 2 = 105.5

LSA = 120

subtract 120 from 105.5 = -14.5 IO

subtract -14.5 from 180 = 165.5

subtract 165.5 from 211 = 45.5 IC

Intake timing = IO -14.5 atdc --- IC 45.5 abdc
__________________________________________________ __________________

Exhaust Timing calcs:

exhaust duration = 230

divide by 2 = 115

LSA = 120

subtract 120 from 115 = -5 EC

subtract -5 from 180 = 175

subtract 175 from 230 = 55 EC

Exhaust timing = EO 55 bbdc --- EC -5 btdc
__________________________________________________ _________________

IO - -14.5 atdc

IC - 45.5 abdc

EO - 55 bbdc

EC - -5 btdc
__________________________________________________ _________________

To advance the cam, subtract the amount of advance in degrees from the intake and add to the exhaust.


To retard the cam, add the amount of retard in degrees to the intake and subtract from the exhaust.


Straight up 120 - ILC/120 - ELC

IO - -14.5 atdc

IC - 45.5 abdc

EO - 55 bbdc

EC - -5 btdc


Example: 3 degrees advance becomes 117 - ILC/223 - ELC


IO - -11.5 atdc

IC - 42.5 abdc

EO - 58 bbdc

EC - -8 btdc
__________________________________________________ ________________

Straight up 120 - ILC/120 - ELC

IO - -14.5 atdc

IC - 45.5 abdc

EO - 55 bbdc

EC - -5 btdc


Example: 3 degrees retard becomes 223 - ILC/117 - ELC


IO - -17.5 atdc

IC - 48.5 abdc

EO - 52 bbdc

EC - -2 btdc

 

26 mpg

 

i jus copied and pasted

 

nasty for a "stock" cam