a bit confused
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Teching In
Joined: Feb 2019
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a bit confused after rebuilding my ls1 with a heads and cam package and ls7 lifters and had measured at 0 lash to be at 7.300. after recommendations a ran a 7.400 pushrod length and the valvetrain was a bit noisy. so I remeasured at 7.300 again so I order 7.375 pushrods after the install the valve train noise was less but im still getting noise in the rpms and idle. so long short I do not want to keep wasting money on pushrods and not get the outcome I am looking for. I have a btr stage 2 cam for ls1 and prc ls6 heads milled .020. what are your thoughts?
Thread Starter
Teching In
Joined: Feb 2019
Posts: 14
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Eo ic EO IC method. I have done it twice and have gotten 7.300 same time. First time I tried .100 of preload for pushrod then today at 7.375. Noise was quiter but still have the notorious sewing machine sound. After some extensive research you want around .50-.60 for ls7 lifters.
I’ve set up preload all over the place. I like .070” preload with LS7 lifters. Seems quietest for me, with those lifters. Not sure why, but titanium retainers helps remove a lot the sewing machine sound. Ramp rates (lobe family) of camshaft, and even oil viscosity will affect the sewing machine sound also. Most hydraulic cams make the sound in some fashion with the ls platform, so don’t feel like the Lone Ranger.
Thread Starter
Teching In
Joined: Feb 2019
Posts: 14
Likes: 0
I’ve set up preload all over the place. I like .070” preload with LS7 lifters. Seems quietest for me, with those lifters. Not sure why, but titanium retainers helps remove a lot the sewing machine sound. Ramp rates (lobe family) of camshaft, and even oil viscosity will affect the sewing machine sound also. Most hydraulic cams make the sound in some fashion with the ls platform, so don’t feel like the Lone Ranger.
Are you measuring for every pushrod? It is a bit tedious but when I did my build I measured for each pushrod, wrote down the numbers, ordered a few different sizes of pushrods, measured each physical pushrod, and matched them to their best fit location on the engine.
LS7 lifters should be fairly forgiving but it doesn't hurt to get them all as closely matched as possible.
LS7 lifters should be fairly forgiving but it doesn't hurt to get them all as closely matched as possible.
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I thought GM wanted like .090 preload and tick or btr says they like to go .100, .060 .070 ain't enuff, I'm running a set of crane gold race adjustable roller rockers and they want .082 or two turns of the adjusting nut, I just did Trick flow heads/LS7 lifters and they call for 7.500 PR's my kit came with 7.250 PR's set up for their kit, Sooo the deck on these heads are .100 thicker Soo that would up the kit length to 7.350 and I'm running a higher lift/duration cam, don't know the base circle but it can't be that much different, Soo I went with a 7.375 PR. and it still sounds like a sewing machine. but it runs wonderfully! I can't believe any things wrong? but I wish I could get it quieter, but remember you hear things in a aluminum engine you don't hear in a steel
Last edited by cmysix; Mar 6, 2019 at 10:39 AM.
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Teching In
Joined: Feb 2019
Posts: 14
Likes: 0
I thought GM wanted like .090 preload and tick or btr says they like to go .100, .060 .070 ain't enuff, I'm running a set of crane gold race adjustable roller rockers and they want .082 or two turns of the adjusting nut, I just did Trick flow heads/LS7 lifters and they call for 7.500 PR's my kit came with 7.250 PR's set up for their kit, Sooo the deck on these heads are .100 thicker Soo that would up the kit length to 7.350 and I'm running a higher lift/duration cam, don't know the base circle but it can't be that much different, Soo I went with a 7.375 PR. and it still sounds like a sewing machine. but it runs wonderfully! I can't believe any things wrong? but I wish I could get it quieter, but remember you hear things in a aluminum engine you don't hear in a steel