LS7 Noise. Pushrod hitting the head?
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LS7 Noise. Pushrod hitting the head? Any ls7 experts here? I need some input. May the ls7 lifter tic at 1800-2200 rpm be caused by the pushrod hitting the head? Any thoughts? Thanks
Last edited by Tallmadgeautomotive; Jun 20, 2018 at 04:46 PM. Reason: typo
Not likely. Besides, what makes you think the pushrods are rubbing on the heads? If they are, then something isn't right.
I have LS7 heads and stock rockers with LS7 lifters and a LSX454 cam. Mine makes a good amount of noise at 1800-2200 as well. I'm using stock LS7 8.415" pushrods. I think I might try 8.450" pushrods to get a little more preload on the lifter and see if that helps quite it down a little.
I did notice that when I switched from 15w40 Rotella oil during break-in to Mobil 1 10w30 the lifters got quieter, but not by much.
I have LS7 heads and stock rockers with LS7 lifters and a LSX454 cam. Mine makes a good amount of noise at 1800-2200 as well. I'm using stock LS7 8.415" pushrods. I think I might try 8.450" pushrods to get a little more preload on the lifter and see if that helps quite it down a little.
I did notice that when I switched from 15w40 Rotella oil during break-in to Mobil 1 10w30 the lifters got quieter, but not by much.
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I dont know if the pr are hitting. im gonna pull a few this weekend . SOMETHING is making this noise 
i have read where pushrod deflection/clearance may be an issue causing this noise. i dunno but this sucks. I took my 77yo dad on a 2 hour trip and on the way back he said "i think your tappets need adjustin there kiddo" just tired of this noise.
i have read where pushrod deflection/clearance may be an issue causing this noise. i dunno but this sucks. I took my 77yo dad on a 2 hour trip and on the way back he said "i think your tappets need adjustin there kiddo" just tired of this noise. Valve guides if you do a search about valve guide and dropped valves. Seems there is a big issue with them. I would do the wiggle test before I drive much could save you a engine and money.
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From: Central Texas
All LS motors are notorious for what is commonly referred to as a "sewing machine" sound, predominately at RPM ranges from 1,600 to 2,100 or so. TSP talks about how their cam lobe profiles help eliminate some of this noise. I also think my Johnson 2110 lifters at .039" of preload and CHE trunnion kit helped quiet things down a lot, as well on my LS7.
https://www.texas-speed.com/t-camshafts.aspx
https://www.texas-speed.com/t-camshafts.aspx
My 434” with solid camshaft is the quietest ls engine I’ve ever heard running. There is zero valvetrain noise. On the other hand, my ls2 with ls3 topend has the typical sewing machine sound, and at cruise speeds, would drive me crazy.
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I think the big difference with the truck motors is that they are much more insulated and even sit a little further away from the motor, unlike a Z06 Corvette, for example. Have had a couple 2003 Z06's and a C6 Z06 LS7 and it was there on all of them. I think you can reduce the amount of pre-load on the stock GM lifters and maybe quiet it down a little bit. I think the GM LS7 lifters were like .120" of preload from the factory on 7.800" PR's in the LS7, and AHP routinely re-installs 7.775" PR's in all of their LS7 cylinder head rebuilds on stock lifters.
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Verdad Gallardo I think the big difference with the truck motors is that they are much more insulated and even sit a little further away from the motor, unlike a Z06 Corvette, for example. Have had a couple 2003 Z06's and a C6 Z06 LS7 and it was there on all of them. I think you can reduce the amount of pre-load on the stock GM lifters and maybe quiet it down a little bit. I think the GM LS7 lifters were like .120" of preload from the factory on 7.800" PR's in the LS7, and AHP routinely re-installs 7.775" PR's in all of their LS7 cylinder head rebuilds on stock lifters.