LT Rocker arm question
Race Director
Joined: Feb 2003
Posts: 11,671
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From: Lake Wylie SC
Originally Posted by spinedoc
Has anyone ever changed cams, springs, etc. in thier LT motor and kept the non adjustable rocker arm setup?
Race Director
Joined: Dec 2002
Posts: 13,348
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by spinedoc
My LT4 has the 'zero lash', tighten type Crane rockers. You don't have to check for any lash, you just tighten them down all the way to the stud.
Zero lash doesn't mean "non-adjustable"........
We may be confusing "zero lash" with hydraulic lifters (which LT-4's have) and even hydraulic lifters have a certain amount of "lash".
Larry
Last edited by rocco16; Aug 6, 2004 at 02:56 PM.
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Originally Posted by code5coupe
Something has to be adjustable....it's either the rockers or the pushrods and I don't think the pushrods are.
Zero lash doesn't mean "non-adjustable"........
We may be confusing "zero lash" with hydraulic lifters (which LT-4's have) and even hydraulic lifters have a certain amount of "lash".
Larry
Zero lash doesn't mean "non-adjustable"........
We may be confusing "zero lash" with hydraulic lifters (which LT-4's have) and even hydraulic lifters have a certain amount of "lash".
Larry
FWIW, aftermarket LT4 heads (i.e. those in the HOT Cam kits, factory LT4 replacement heads, etc) are shipped with the conventional 3/8" LT1 style rocker arm studs.
Regarding the original posters question...Some have run the HOT Cam with the OEM non-adjustable rockers. Most like to be able to adjust the rockers to a desired amount of lash.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
I think it's a matter semantics - all hydraulic lifters need a certain amount of preload which for most Chevy V6'S and V8's is one turn down from zero lash. When you use a torque value, which is somewhat common place in the shop manuals these days, you're accomplishing the same thing - adjusting the preload. Go to www.cranecams.com for more info.
Other than a pushrod measuring tool, I don't know of any adjustable pushrod. Pushrods are available in different lengths and you will need a different length if you use a thinner or thicker head gasket, mill the heads or the deck surface or do anything that changes rocker arm geometry - which for GM should be 90 degrees between the rocker arm and valve stem at 1/3 lift.
Other than a pushrod measuring tool, I don't know of any adjustable pushrod. Pushrods are available in different lengths and you will need a different length if you use a thinner or thicker head gasket, mill the heads or the deck surface or do anything that changes rocker arm geometry - which for GM should be 90 degrees between the rocker arm and valve stem at 1/3 lift.
