Edrummr

iTrader: (1)

I'll be running LSL lobes with .603" intake lift and .613" exhaust lift with what is essentially a stock '02+ LS6 valvetrain plus 1518 beehives.

My expectation is that the motor will run out of breath by 6500 - either way, my rev limiter will be 6500 or lower.

I've measured the unshimmed install heights to all be just a hair under 1.800.

I'm now considering doing one of the following:

(Option, Intake shim, Exhaust shim)
A, .015", .000"
B, .030", .015"

I'm targeting the typical... reliability, spring life, float avoidance, miss-shift tolerance (as practical - M6). BTW, the car will be street driven w/ occasional WOT romps.

What approach to shimming makes most sense with this application and the light valves? I know there isn't too much of a difference between the options described, but I'd like to understand why one might be better than the other.

Thanks for any input!

Over-torque

bump....id like some info as well

KCS

iTrader: (20)

Have you measured where your springs go into coilbind?

Edrummr

iTrader: (1)

I have not measured actual spring coil bind length. The 1518 max coil bind length is published by the mfg. I'm a comfortable margin away from that as well as from 'max lift' relative to the recommended install height.
Are you suggesting I should shim to within x of bind? If so, are you confident that I need the additional pressure? Is resonance the issue? Just trying to avoid working the springs harder than necessary to control the valvetrain...

A.R. Shale Targa

iTrader: (2)

I wouldn't recommend shimming them any tighter than the specified 1.800
installed height....If for some reason you want more than 130 seat load
or just additional piece of mind try PSI maxlife beehives w/135 and 370psi
@ .625 lift or Lunati dual Golds are an ecconomical kit @ $225 for seats,locks
seals,tool steel retainers, and 150 @ 1.810; 390 @ .650 lift

theevette

iTrader: (2)

I thought these springs were direct drop in with no shimming.

outkast6991

iTrader: (34)

they are. setting the installed height and shimming xx amount from coil bind are for spring pressures and valve control

vettenuts

iTrader: (4)

I would contact COMP for a recommended seat value, but be sure to get someone who knows what they are talking about. Some of the tech support I have gotten from them was stupid. The other issue you have is the LS6 lightweight valves have had some issues with big spring forces so you want to go with only that necessary to control the valve train. Without good data on the required seat value, I think I would target 135# - 140# on the seat and see how it does on the dyno.

KCS

iTrader: (20)

If I remember correctly, the LSL lobes are a little on the aggressive side. I don't think you would be able to get enough spring pressure out of the 1518 springs to hurt anything, so I'd recommend getting every bit that you can. The general rule of thumb is .060" from coilbind. Just the act of getting the coils closer to coilbind helps control the valvetrain better, and yes, its a resonance thing.

farmington

iTrader: (14)

When you check them for coil bind height, make sure you're using the retainer too. It can make a difference.