LS6 / Z06 CAM Question
Thread Starter
Staging Lane
Joined: Aug 2007
Posts: 61
Likes: 0
From: East Tennessee
LS6 / Z06 CAM Question I am doing a complete rebuild of my LS1 and here is my recipe:
Wiseco 383 Stroke Kit (With Forged Pistons, Forged K1 Crank, & Forged Rods)
Patriot Performance Predator CNC Ported Heads
FAST 102mm Intake & 102mm Throttle Body
Harland Sharp 1.8 Ratio Roller Rockers
2002-2004 LS6 CAM Shaft - 204/218 - 0.550/0.550 - 117.5 LSA
(11.19 Static Comp Ratio / 10.36 Dynamic Comp Ratio)
When doing my CAM shaft and engine calculatoins, I determined that the intake valve doesn't open till 15.5deg (crank) After TDC and closes 39.5deg After BDC. This is all assuming that the CAM shaft doesn't come with any built in advance. I can somewhat understand why the delay in closing the intake valve because of the 'Dynamic Compression Ratio', but I don't understand why it takes 15.5 deg before opening. I am seeking a strong 'Street' motor with very good CAM manners, and with absolutely no overlap, I'm guessing this will be a well behaved CAM. Can someone help me understand why the 15.5 deg delay?? Also, love some comments on the recipe. I have also attached my engine setup calculations for review. Please let me know your thoughts. THANKS!!
Wiseco 383 Stroke Kit (With Forged Pistons, Forged K1 Crank, & Forged Rods)
Patriot Performance Predator CNC Ported Heads
FAST 102mm Intake & 102mm Throttle Body
Harland Sharp 1.8 Ratio Roller Rockers
2002-2004 LS6 CAM Shaft - 204/218 - 0.550/0.550 - 117.5 LSA
(11.19 Static Comp Ratio / 10.36 Dynamic Comp Ratio)
When doing my CAM shaft and engine calculatoins, I determined that the intake valve doesn't open till 15.5deg (crank) After TDC and closes 39.5deg After BDC. This is all assuming that the CAM shaft doesn't come with any built in advance. I can somewhat understand why the delay in closing the intake valve because of the 'Dynamic Compression Ratio', but I don't understand why it takes 15.5 deg before opening. I am seeking a strong 'Street' motor with very good CAM manners, and with absolutely no overlap, I'm guessing this will be a well behaved CAM. Can someone help me understand why the 15.5 deg delay?? Also, love some comments on the recipe. I have also attached my engine setup calculations for review. Please let me know your thoughts. THANKS!!
that cam is way too light for a 383 LS, if you wanna make power get something bigger...the extra cubes and compression will eat up a way bigger duration cam than that, dont waste your time or money do it right the first time
TECH Fanatic
Joined: Jun 2011
Posts: 1,343
Likes: 8
From: Katy, TX
your calculations used the cam duration figures at .050 lift. use the duration numbers at .006 lift to accurately calculate your DCR and valve events relative to crank rotation. This will show that the intake valve starts to open before TDC.
I also suggest a longer duration cam, 220 at least on the intake (.050). The longer stroke needs this to maintain the DCR in the optimum range.
And if you are open to other suggestions, if you machine .010 off the deck and run a .040 head gasket, you could achieve a .030 quench. This will require running 65cc heads to keep your compression ratio.
Good luck!
I also suggest a longer duration cam, 220 at least on the intake (.050). The longer stroke needs this to maintain the DCR in the optimum range.
And if you are open to other suggestions, if you machine .010 off the deck and run a .040 head gasket, you could achieve a .030 quench. This will require running 65cc heads to keep your compression ratio.
Good luck!
Last edited by RezinTexas; Jan 9, 2012 at 06:12 AM.
Thread Starter
Staging Lane
Joined: Aug 2007
Posts: 61
Likes: 0
From: East Tennessee
Thanks for the reply. That makes sense on using the 0.006 lift for valve timing events. If I went with a 220 duration, what kind of LSA would you recommend?? I really don't want a 'grumpy idle'... (Been there and done that!!) Any CAMs that you would recommend??
This is a joke right?
Please don't build a 383 forged car and run a LS6 cam.
Get Pat G or someone with EPS to custom spec you something for EXACTLY what you want. He can set you up with a higher LSA (115+) so you don't have a rough idle. Its only like $25 bucks more at that.
He spec'd a "sleeper cam" for a stock LS6 engine (stock 243 heads and LS6 intake) that made like 420 or 440 to the wheels through an auto that idled near stock!
Please don't build a 383 forged car and run a LS6 cam.
Get Pat G or someone with EPS to custom spec you something for EXACTLY what you want. He can set you up with a higher LSA (115+) so you don't have a rough idle. Its only like $25 bucks more at that.
He spec'd a "sleeper cam" for a stock LS6 engine (stock 243 heads and LS6 intake) that made like 420 or 440 to the wheels through an auto that idled near stock!
Teching In
Joined: Feb 2007
Posts: 23
Likes: 0
LS6 cam with 1.8's will also be likely to float... thats some pretty insane jerk rate. my buddy made 45x with a cracked piston in his stock shortblock LS1 with an LS6 cam and some heads... you might want to call a cam guy and have him spec you something, a stroker motor takes a completely different kind of cam than a stock motor, piston speeds are pretty different.
TECH Fanatic
Joined: Jun 2011
Posts: 1,343
Likes: 8
From: Katy, TX
Although I am attempting to spec my own cam for my build (which is the same rotating assembly as yours, iron block, factory truck manifold) I can't stand behind my numbers yet. I will probably end up having one spec'd by an experienced person (probably Pat G).
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For sure, I would be running mid to high 220s in duration, prob low 230s in duration...your engine has almost 40 more cubes than stock! Custom cam is the way to go when u got the cash for it.
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Most people will frown upon using an LS6 cam in a stock cube LS1, let alone a stroked 383. Go bigger, way bigger. You can make good power while still maintaining a good idle/driveability if you do it right
No tuning required?! Are you joking?
I bet 37 extra cubes will run great on a stock tune.
That and the gigantic intake and ported heads.
LS6 cam would be great for a stock LS1 that doesn't want tuning or sacrifice.
This guy is building a forged 383.
