Pushrod length ERL Superdeck 6 & Johnson lifters - LS1TECH - Camaro and Firebird Forum Discussion



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Pushrod length ERL Superdeck 6 & Johnson lifters

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Old 03-06-2017, 11:28 AM   #1
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Default Pushrod length ERL Superdeck 6 & Johnson lifters

So my first time measuring Pushrod length, I have my cylinder #1 TDC lifter on base circle, push rod length checker in and it takes 17 turns to get to zero lash giving me a base pushrod length of 7.65. So I add the .035 Johnson recommended pre-load for the 2116LSR lifters giving me total length of 7.685 for push rods. The cam came with the recommendation for 7.4 pushrods. It also takes approximately 1/4 maybe a little more of a turn to get to 22ft/lbs from zero lash which seems low to me.

I am curious as to the difference in the recommendation and the actual measurements. Could it be the recommendations are for a normal block not a re-sleeved superdeck from ERL, Also using PRC 255 heads that have been milled to 69cc, and minimally resurfaced. Would the difference in stock block vs superdeck, aftermarket heads, and Johnson 2116 LSR be whats accounting for difference in the recommended length and measured length?
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Old 03-06-2017, 01:07 PM   #2
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So my first time measuring Pushrod length, I have my cylinder #1 TDC lifter on base circle, push rod length checker in and it takes 17 turns to get to zero lash giving me a base pushrod length of 7.65. So I add the .035 Johnson recommended pre-load for the 2116LSR lifters giving me total length of 7.685 for push rods. The cam came with the recommendation for 7.4 pushrods. It also takes approximately 1/4 maybe a little more of a turn to get to 22ft/lbs from zero lash which seems low to me.

I am curious as to the difference in the recommendation and the actual measurements. Could it be the recommendations are for a normal block not a re-sleeved superdeck from ERL, Also using PRC 255 heads that have been milled to 69cc, and minimally resurfaced. Would the difference in stock block vs superdeck, aftermarket heads, and Johnson 2116 LSR be whats accounting for difference in the recommended length and measured length?
The recommendation is probably for OEM style heads/lifters. The aftermarket castings often have a taller rocker mount so you end up with longer pushrods. The lifters don't require as much preload, plus they could have a different cup height, both of which would skew the pushrod length as well.
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Old 03-06-2017, 01:56 PM   #3
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Can you explain this part: "It also takes approximately 1/4 maybe a little more of a turn to get to 22ft/lbs from zero lash which seems low to me."

The rockers should be on and tight when checking pushrod length, with regular rocker stands. If you are doing studs and rockers like an old school SBC, it's a different story.

It should go something like this if you have regular LS style rockers.
1. Insert checking pushrod through head down in to lifter cup.
2. Install and torque rocker arm.
3. Extend pushrod checker out until you have zero lash, keeping a watchful eye that you are not compressing the lifter or the spring.
4. Add the recommended preload from your lifter manufacturer.
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Old 03-06-2017, 02:09 PM   #4
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I thought one turn of the pedestal bolt = .047 of preload from zero lash on LS3 style heads. Everything else is how I did it, I just using the old method of making sure I am in the correct range for preload counting turns from zero lash to the torque value.
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Old 03-13-2017, 07:15 AM   #5
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Originally Posted by 96 Comp T/A View Post
Can you explain this part: "It also takes approximately 1/4 maybe a little more of a turn to get to 22ft/lbs from zero lash which seems low to me."

The rockers should be on and tight when checking pushrod length, with regular rocker stands. If you are doing studs and rockers like an old school SBC, it's a different story.

It should go something like this if you have regular LS style rockers.
1. Insert checking pushrod through head down in to lifter cup.
2. Install and torque rocker arm.
3. Extend pushrod checker out until you have zero lash, keeping a watchful eye that you are not compressing the lifter or the spring.
4. Add the recommended preload from your lifter manufacturer.
THIS... i think your complicating it. This is how i did it and i have zero valvetrain noise
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Old 03-13-2017, 07:29 AM   #6
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Why they recommend a normal block over a resleeved block ?
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Old 03-14-2017, 05:20 PM   #7
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I think the cam was just giving a general rec. its always better to actually measure. Go with your measurements
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Old 03-14-2017, 05:53 PM   #8
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PRC heads like that typically require a longer rod. Seems to be in the ballpark.
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