Question about valve spring install
Question about valve spring install Hi all,
I'm planning to run the light LS6 valves, stock rockers (w/ new trunions), and PAC 1518 valve springs in an LS1 w/ 243 heads (N/A).
I would like to use the following LSL lobes:
Intake: 13014R 265 215 139 .604”
Exhaust: 13017R 277 227 151 .614”
I do not plan to rev past 6500.
Question: PAC recommends an installed height of 1.800" for these springs. Will I be ok to install at that height, or will I need to shim to within 0.050" of coil bind to tame spring surge?
If I need to shim, I understand I will need to take measurements. However, I would like to know the ID and OD of the shims I will need.
Thanks for your help!
I'm planning to run the light LS6 valves, stock rockers (w/ new trunions), and PAC 1518 valve springs in an LS1 w/ 243 heads (N/A).
I would like to use the following LSL lobes:
Intake: 13014R 265 215 139 .604”
Exhaust: 13017R 277 227 151 .614”
I do not plan to rev past 6500.
Question: PAC recommends an installed height of 1.800" for these springs. Will I be ok to install at that height, or will I need to shim to within 0.050" of coil bind to tame spring surge?
If I need to shim, I understand I will need to take measurements. However, I would like to know the ID and OD of the shims I will need.
Thanks for your help!
Those are good springs but call comp cams to verify the seat and open pressures suffice for the lobes. Second you will want to measure install height find the lowest one then that is your install height. The proper way to do it from there is magnetic base with a dial indicator to measure actual lift of the cam by placing it on the retainer and measuring when the valve is full open. Subtract this number from your install height and them shim as needed to get it within .050
Cool, I can do that. So assuming my pressures are sufficient, I will need to shim within 050 of coil bind to do this right. I'm going to go ahead and pick up some shims that I can combine to get me close to the following basic thickness estimates:
(Basic assumptions: Coil bind ~ 1.09", 243 "installed height" ~ 1.800")
1.800 - 1.09 - .604 - .050 = 0.056
1.800 - 1.09 - .614 - .050 = 0.046
So what ID and OD shims should I get?
(Basic assumptions: Coil bind ~ 1.09", 243 "installed height" ~ 1.800")
1.800 - 1.09 - .604 - .050 = 0.056
1.800 - 1.09 - .614 - .050 = 0.046
So what ID and OD shims should I get?
Last edited by Edrummr; Oct 8, 2010 at 12:28 PM. Reason: Forgot to subtract the .050" - oops
Anyone know the valve spring shim dimensions? 
