LT1-LT4 Modifications 1993-97 Gen II Small Block V8

rocker geometry help

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Old May 10, 2013 | 07:31 AM
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Default rocker geometry help

Hey guys I'm running into an issue while trying to find my pushrod length. The issue I'm having is that no matter what the pushrod length this is the best I can get. In order to get better results I have to tighten the rocker down so much that it binds on the rocker stud. These are nsa crane golds 7/16 stud. And I'm using a comp cams adjustable pushrod.

Do I just need to clearance where the stud goes? These are on le2 heads



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Old May 10, 2013 | 07:51 AM
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looks to me like the PR is just too short for you......what number you come up with for length?
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Old May 10, 2013 | 07:57 AM
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Agreed, something is wrong here.
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Old May 10, 2013 | 08:21 AM
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Ya something is fundamentally wrong. I'm going to call crane and verify these are even SBC rockers. I bought them used with no packaging.

The top photo is near stock length PR and the bottom picture is what happens when I shorten the PR to pattern more correctly
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Old May 10, 2013 | 08:54 AM
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are you tightening the rocker to the point where it collapses the piston in the lifter?
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Old May 10, 2013 | 08:57 AM
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Do you have a stock rocker arm and pushrod to put on to check clearance? I would definitely go back to basics to see.
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Old May 10, 2013 | 08:59 AM
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no but it collapses when i roll it over but a have a set of low tension springs on another cylinder for checking ptv clearance. i want to get the correct geometry before i bother checking ptv though
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Old May 10, 2013 | 09:00 AM
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Originally Posted by 96lt1m6
Do you have a stock rocker arm to put on to check clearance? I would definitely go back to basics to see.
ya in a box somewhere but i would have to swap out a stud to try. i was going to do that but i cant find the retaining nut for it
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Old May 10, 2013 | 09:03 AM
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Originally Posted by 05_quick4door
no but it collapses when i roll it over but a have a set of low tension springs on another cylinder for checking ptv clearance. i want to get the correct geometry before i bother checking ptv though
Use the cylinder with the light springs to check geometry. If you check geometry while the lifter is collapsing the geometry will never be correct.
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Old May 10, 2013 | 09:13 AM
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Originally Posted by BOOSTED AFR
Use the cylinder with the light springs to check geometry. If you check geometry while the lifter is collapsing the geometry will never be correct.

i started doing that after a few tries and im getting near the same results.

going to call crane to verify their hieroglyphics on the rockers.
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Old May 10, 2013 | 09:19 AM
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Originally Posted by BOOSTED AFR
Use the cylinder with the light springs to check geometry. If you check geometry while the lifter is collapsing the geometry will never be correct.
what he said
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Old May 10, 2013 | 09:22 AM
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just got off the phone with crane. they are sbc 1.6s but since they have the 7/16 hole they wont work with the center bolt valve covers. im going to look and see if its just a little clearing needed to make it work.

but i think im going to start back over trying to find the correct length.
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Old May 10, 2013 | 09:24 AM
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I use 1.6 Crane Gold 7/16" rocker on my 93 Corvette. They fit perfectly but they are underneath composite valve covers from an LT4
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Old May 10, 2013 | 09:30 AM
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Originally Posted by BOOSTED AFR
I use 1.6 Crane Gold 7/16" rocker on my 93 Corvette. They fit perfectly but they are underneath composite valve covers from an LT4
my buddy and me just jammed a set of crane gold 1.7 7/16" rockers inside stock impala valve covers...........trust me they'll fit with a die grinder lol
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Old May 10, 2013 | 09:48 AM
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So after trying again getting the same results I notice something. On the right is a 3/8 stud that was on the heads when I bought them. On the left is the new 7/16 stud I bought. Looks at the difference in the radius.

Does the new stud seem overly large where it flairs to what you guys use?

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Old May 10, 2013 | 10:00 AM
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Well! Alittle bit of this action



Lead to alittle bit of this action! Sorry my marker sucks

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Old May 10, 2013 | 10:08 AM
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Good lord man, have to get all same studs. Those are 7/16ths rocker arms it looks like.
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Old May 10, 2013 | 10:11 AM
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Originally Posted by 05_quick4door
The one on the left is the stud you should be running. It is a tapered stud made specifically for clearance purposes so the rocker will not bottom out, like what you have going on...
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Old May 10, 2013 | 10:23 AM
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Well! Alittle bit of this action



Lead to alittle bit of this action! Sorry my marker sucks

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Old May 10, 2013 | 10:30 AM
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My phone is going crazy....

The one in the left is the one I am using. Its a 7/16.

The one on the right was for comparison reasons. To show how large the radius shoulder is on the 7/16 stud. That's why the rocker was contacting it. I clearenced the rocker and problem solved. I measured that I need a PR length of 6.950.

Sound within reason?
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