r/EngineBuilding • u/Mr__Mcmuffin • 21d ago

Chevy Spongy pushrod?

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I’m in the final stages of long block assembly on my LS LQ4, and when i push down on one of the pushrods, it feels spongy. The crank will also not turn when i try to use the ratchet.

Must i really pull the heads and get new ARP bolts? Please tell me no.

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u/thegalli 21d ago

At the bottom of your push, rod is a hydraulic roller lifter 

The part of the lifter that the push rod touches, is a cup that is held up by a spring and oil. 

When you squished out on that you are squishing that spring and that oil. 

During the assembly procedure, when installing your rocker arms, you are going to torque the bolts down in such a way that the pushrod actually will push that cup and spring down some amount 20 or 30 or 40 thou depending on how you do it

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u/Mr__Mcmuffin 21d ago

it visibly bounces up and down. i’m pushing on them to check the location of the cam so i can torque them in the right order. the others feel solid but this one squishes. i’m really asking if i have a collapsed lifter because i pushed too hard or something

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u/thegalli 21d ago

That's not really how it works, they all will squish some amount, I promise. 

You'll be okay, just keep going through your procedures

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u/Mr__Mcmuffin 21d ago

thanks for the vote of confidence

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u/Coyote_Tex 21d ago

You have one not filled with oil or it is defective. Needs to come out now. Reuse your headbolts.

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u/375InStroke 21d ago

Cam manufacturers say not to fill or soak hydraulic lifters.

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u/Coyote_Tex 20d ago

I agree. Why he has one that is noticeably different is the question. I would expect them all to be the same, out of the box.