LS1 preload (not LS7)
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Teching In
Joined: Jun 2024
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LS1 preload (not LS7) I’ve been scouring the internet endlessly and maybe my Google fu is fading with age but I’m not having luck finding the lifter plunger travel for the original LS1 lifters. Reason being running 7.4” with summit 8720 cam on my 2000 c5 and I’m coming up with .08” preload. I’m using an adjustable pushrod to measure. 0 lash on intake and exhaust is 7.315”. If these were LS7 lifters I’d be on the money however everyone seems to say the original ls1’s have less travel and “ideal” is .06” preload. I’m having trouble finding a max safe preload or if I should just go with a 7.375” pushrod to get that magical number or keep the 7.4’s @ .08” preload. Engine isn’t really noisy or anything.
I’ve been scouring the internet endlessly and maybe my Google fu is fading with age but I’m not having luck finding the lifter plunger travel for the original LS1 lifters. Reason being running 7.4” with summit 8720 cam on my 2000 c5 and I’m coming up with .08” preload. I’m using an adjustable pushrod to measure. 0 lash on intake and exhaust is 7.315”. If these were LS7 lifters I’d be on the money however everyone seems to say the original ls1’s have less travel and “ideal” is .06” preload. I’m having trouble finding a max safe preload or if I should just go with a 7.375” pushrod to get that magical number or keep the 7.4’s @ .08” preload. Engine isn’t really noisy or anything.
Id leave it alone for a couple reasons.
1. I like my hydraulics set up on the deeper end of preload for less lifter bleed down, and they tend to run quieter.
2. Thermal expansion. The aluminum block and heads will grow approx .010 making that pushrod “seem” shorter at temp, therefore removing preload.
And just to throw a number three in here, you stated it’s not noisy, so I’m ASSuming it’s running fine. Honestly I’m not sure there’s a preload difference between the original lifter and the LS7 replacements anyway. Leave it alone.
Thread Starter
Teching In
Joined: Jun 2024
Posts: 10
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Thank you che70velle. That makes sense. It is running good but I’m in the middle of tuning so not 100% there yet.
the_merv, I kept coming across the .08 also but it seemed that everyone was referring to ls7 lifters. If it’s the .08” for the ls1’s then I’m right on the money. Looks like I’m gonna just roll with it the way it is anyway. Appreciate it.
the_merv, I kept coming across the .08 also but it seemed that everyone was referring to ls7 lifters. If it’s the .08” for the ls1’s then I’m right on the money. Looks like I’m gonna just roll with it the way it is anyway. Appreciate it.
