Lifter preload delema
I would have jumped in earlier, but I didn’t want to add to your frustration. Now that your good...There are obvious multiple ways to get to where you need to be with preload. I’ve never liked the counting turns style personally. Does it work? Sure. Just not for me. What I do for my hydraulic builds with LS7 lifters is, I have a new LS7 lifter that I gutted, and filled with shim stacks, so it’s effectively a solid lifter. The plunger is at the top against the clip, with zero play. It’s tricky to setup, but you only have to do it once.(throw it in the toolbox when done. I’ve used it multiple times) I drop it in, and use the adjustable pushrod. With the rocker torqued, and a check spring in place of valvespring, I adjust the pushrod until I have firm contact in both cups. I’ll turn the engine over a couple times and check my adjustable pushrod again. Once I’m cool with the adjustable pushrod, I unbolt the rocker, and pull the pushrod. Measure the length, end to end with a caliper, and add suggested preload to the dimension. Done. Takes maybe 10 minutes during mock-up. I make sure to tell whomever I’m ordering my pushrods from how I measured the adjustable pushrod. Pretty foolproof.
Thread Starter
Teching In
Joined: Jul 2018
Posts: 31
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The only pain in the a$$ doing it that way is having to torque the heads down and take them back off again. With the nightmare I had stripping the m8 bolts, that would have added to it. But yup, that sounds a lot easier. My mistake i think, besides trusting a dozen youtube videos, lsx magazine, and others, was measuring with the heads snugged and guessing what the uncompressed thickness of the head gasket was.
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
Gotta say Scott, your method seems VERY foolproof! Kind of a no-miss policy! And yeah telling the pushrod seller how you did it puts you both on the same page. Good communication is always good!
The only pain in the a$$ doing it that way is having to torque the heads down and take them back off again. With the nightmare I had stripping the m8 bolts, that would have added to it. But yup, that sounds a lot easier. My mistake i think, besides trusting a dozen youtube videos, lsx magazine, and others, was measuring with the heads snugged and guessing what the uncompressed thickness of the head gasket was.
No need to torque the heads down. Roll the engine stand until the bank your checking is level. I set valve spring shims (.030) on the deck surface, centered on the head bolt holes. This keeps the head off the deck, incase your pistons are out of the hole. Set the head on the shims carefully, and start several head bolts. Run them down until they are snug. DO NOT tighten the headbolts, just nice and snug. The valvespring shim is steel and won’t compress, so there’s no guessing to do with this setup. Do a little simple math to figure what the difference is between the valve spring shim, and the compressed thickness of the gasket you’ll be using. ADD the difference to your pushrod length, once you figure it out with the adjustable pushrod checker. Done. Very simple and quick method. Tony Mamo told me he does it the same way. If it’s good enough for Tony, it’s good enough for all of us.
sounds good but for most of us doing this on the ls1 with motor in the car this wouldn't work.....will try this tho when i pull my motor.....so if you know your compressed gasket is .045, and the shims are .030, you just add an extra .015 when u are all said and done
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