pushrod length
02-06-2007, 05:29 PM
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pushrod length i have a 2007 4.8l rcsb
i would like to get a cam with the specs: 216/220 112LSA +4 .561/.564. also i want a thinner head gasket of .42 rather than the stock .52. what size push rods would i need? or is this something im going to have to check when i have it assembled in the truck.
i would like to get a cam with the specs: 216/220 112LSA +4 .561/.564. also i want a thinner head gasket of .42 rather than the stock .52. what size push rods would i need? or is this something im going to have to check when i have it assembled in the truck.
02-07-2007, 11:35 AM
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Originally Posted by mcfarlnd
i have a 2007 4.8l rcsb
i would like to get a cam with the specs: 216/220 112LSA +4 .561/.564. also i want a thinner head gasket of .42 rather than the stock .52. what size push rods would i need? or is this something im going to have to check when i have it assembled in the truck.
i would like to get a cam with the specs: 216/220 112LSA +4 .561/.564. also i want a thinner head gasket of .42 rather than the stock .52. what size push rods would i need? or is this something im going to have to check when i have it assembled in the truck.
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02-09-2007, 01:18 AM
#9
That .010 isn't enough to get a different pushrod length. The hyd. lifter plunger will absorb that .010 with not much effort/effect. Measure the preload on the rocker bolts after you get the cam in and with the stock lifters, if you get somewhere in the 1 turn (+ or - 1/4 turn) range, you should be good to go.
02-09-2007, 02:09 PM
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i just dont want something to get jacked up. i dont want to be guessing around. ill try that and if it dont work ill just measure it.
02-09-2007, 04:23 PM
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Originally Posted by mcfarlnd
i just dont want something to get jacked up. i dont want to be guessing around. ill try that and if it dont work ill just measure it.
02-09-2007, 04:37 PM
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With these non adjustable valvetrains you have to adjust pushrod length to make up the differences. To maintain proper valvetrain geometry it's a PIA with a non adj valvetrain. More than likely your new cam will have a smaller base circle than your stocker. Find that number out and subtract from your stock basecircle. Add that number plus .010 for your gasket and that will give you a calculated length to add to your stock pushrod. This will maintain correct valvetrain geometry with a non adj setup.
You can use your stock pushrods and be fine, but you will no longer have correct valvetrain geometry as the lifter is soaking up the discrepency of the pushrod length.
You want correct valvetrain geometry to keep the rocker tip with a perfect sweep pattern across the top of the valve stem. With a adj setup it's very simple to adjust this.
You can also use a pushrod length checker to verify.
You can use your stock pushrods and be fine, but you will no longer have correct valvetrain geometry as the lifter is soaking up the discrepency of the pushrod length.
You want correct valvetrain geometry to keep the rocker tip with a perfect sweep pattern across the top of the valve stem. With a adj setup it's very simple to adjust this.
You can also use a pushrod length checker to verify.
Last edited by Ryan02SS; 02-09-2007 at 04:43 PM.
02-10-2007, 12:53 AM
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Originally Posted by Ryan02SS
With these non adjustable valvetrains you have to adjust pushrod length to make up the differences. To maintain proper valvetrain geometry it's a PIA with a non adj valvetrain. More than likely your new cam will have a smaller base circle than your stocker. Find that number out and subtract from your stock basecircle. Add that number plus .010 for your gasket and that will give you a calculated length to add to your stock pushrod. This will maintain correct valvetrain geometry with a non adj setup.
You can use your stock pushrods and be fine, but you will no longer have correct valvetrain geometry as the lifter is soaking up the discrepency of the pushrod length.
You want correct valvetrain geometry to keep the rocker tip with a perfect sweep pattern across the top of the valve stem. With a adj setup it's very simple to adjust this.
You can also use a pushrod length checker to verify.
You can use your stock pushrods and be fine, but you will no longer have correct valvetrain geometry as the lifter is soaking up the discrepency of the pushrod length.
You want correct valvetrain geometry to keep the rocker tip with a perfect sweep pattern across the top of the valve stem. With a adj setup it's very simple to adjust this.
You can also use a pushrod length checker to verify.
sorry for all the questions and thanks for the help.
02-10-2007, 10:17 AM
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Originally Posted by mcfarlnd
wouldnt i need to subtract .010 since the gasket is smaller than stock?
sorry for all the questions and thanks for the help.
sorry for all the questions and thanks for the help.
