Ok guys. I have a LMG 5.3 with 243 heads and will be installing a Vinci 080 Ultra Torque cam, 210/218 .551/.551 116+2 110ICL. Now Roger said that LS6 Blue springs would technically work, which is what i have now, but he recommended a better spring. I can get Comp 918s with titanium retainers and hardened keepers for relatively cheap ($250) here locally, or PAC 1218s or 1219s. But he said dual springs is better insurance. I use this truck to tow roughly 6500lbs about twice a month and i would like to see what it does at the drag strip every so often. Might rev it to 6200-6300 max. So i would like a spring that has good longevity and will be quiet also and last maybe 100k miles or so. I know the cam is small so i dont need a crazy spring. The lobes are not very aggressive. Roger said the lobes are comparable to the Comp XFI. What is everyones thoughts and recommendations on what springs to use. I would like to keep everything under $250.

 

I agree with Roger about using dual springs. A broken spring can cause a lot of damage (at least new piston and head). A dual spring will be a little louder (think sewing machine), but if one spring breaks the other will keep the valve off the piston.

 

I personally think a lot of the sewing machine noise is due to incorrect geometry/incorrect pushrod length than the spring type. My duals are quieter and almost stock compared to prior singles with now correct pushrod length.

 

this 100% depending on heads and cam most people can tell you roughly what PR will work. The ones I have actually used the right PR length tool and and got the exact PRs, BTR .660 duals can be made to have no noise

 

This could also be because your lobes are softer and dont close the valve as aggressively. I would tend to think this is the leading reason for a quieter valvetrain now...

 

But there is much more seat pressure....so the valve should be closing with more force now.

Only fact I know for sure.....I previously had the wrong pushrod length and now it is correct.

 

Just an update. I talked to the guys over at Brian Tooley and they said with that small of a cam the LS6 blue springs will be fine. I gave them the cam specs and asked their opinion on springs. They said they are running the LS6s with their truck cams with .563 lift to 6500 RPM and have 20k miles on it and have been fine. Now i wont be revving my engine that high but they insured me it will be fine and will have the best longevity.

 

I understand what youre saying, but no matter the spring pressure the valve can only close as hard as the cam lobe will let it. A pushrod that is slightly too short will likely make the valve bottom out before the lobe would have otherwise let it causing a bit of a 'crash landing'.

What tooley isnt taking into account is the ramp rates on the lobes. Just because they have the same lift and small duration doesnt mean they are a 'soft' lobe.

If you know .006 and .200 lift duration you can kind of make general estimates about that stuff... but otherwise you are flying completely blind.

 

He said he knows the cam really well. But what would you recommend? A single behive with up to .600 lift or a dual .650 spring.

 

ok if he knows the cam really well then I would likely trust his opinion.

All I was trying to point out is that there is a ton more to picking a valve spring than lift and duration.