Lifter Preload
10-03-2015, 12:59 AM
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Lifter Preload
After my cam and head swap on my 5.3 (lm7) the valve train seems to be quiet noisy. I used ls7 lifter, 243s milled .030, hardened 7.4 pushrods, & stock .051 thickness gaskets I understand it's common when changing springs and components that it will be louder than stock but my concern is I can hear a slight ticking at idle and around 1,800 to 2,200 rpm or when cruising on the highway. Doesn't matter if the motor is cold or warm it does it either way. Don't think it's loud enough to be a failed lifter but I'm think maybe the pushrod length isn't correct. I have the pushrod length checker tool. Just not sure how to measure for preload and all that. Thinking maybe a shooter pushrod would help quiet it down? Any help would be appreciated.
Thanks- Kyle
Thanks- Kyle
10-03-2015, 07:55 AM
#3
After my cam and head swap on my 5.3 (lm7) the valve train seems to be quiet noisy. I used ls7 lifter, 243s milled .030, hardened 7.4 pushrods, & stock .051 thickness gaskets I understand it's common when changing springs and components that it will be louder than stock but my concern is I can hear a slight ticking at idle and around 1,800 to 2,200 rpm or when cruising on the highway. Doesn't matter if the motor is cold or warm it does it either way. Don't think it's loud enough to be a failed lifter but I'm think maybe the pushrod length isn't correct. I have the pushrod length checker tool. Just not sure how to measure for preload and all that. Thinking maybe a shooter pushrod would help quiet it down? Any help would be appreciated.
Thanks- Kyle
Thanks- Kyle
Do it right the first time.
10-03-2015, 11:47 AM
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10-03-2015, 11:48 AM
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10-03-2015, 12:23 PM
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Alright, I'll see what I can find. I also found that the max preload you want for ls7 lifters is around .075 or so, I take it the shorter the pushrod is the lower it'll make the preload? Right now I'm probably around the .100 range maybe
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10-03-2015, 02:17 PM
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So from what I understand if I would have ran stock heads the 7.4 pushrod would have been fine and would of had around .075 preload, but since they are milled the preload is now around .105 with the 7.4 pushrod, dropping the pushrod to 7.375 would give me around .080 preload and a 7.350 pushrod would give me .055 preload. Any benefit to either one? Motor will be getting boosted eventually as well.