need help - noise after rebuild
09-15-2021, 10:37 AM
#1
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need help - noise after rebuild Looking for some help here, if anyone has any ideas. My gasser truck sounds like a diesel, but not sure how to describe the noise and videos don't quite capture it but I'll add some if it helps.
Setup:
-fresh un-ran (except idling while troubleshooting) gen 3 factory 6.0 with factory gen 4 internals, balanced before assembly with ws6store rebuild kit for bearings (including cam) and gaskets
-ss2 cam bought new as 1840-p cam
-Stock ls7 lifters from frankenstein (2 sets. Swapped set 1 thinking that was the issue)
-7.450 pushrods (now, after figuring out how to use the checker)
-PAC 1905 springs
-Stock 317s (got them used, no reason to think they've been modified) with trunnion bushing upgrades
-Ls9 gaskets (previously stock. Changed when I replaced lifters)
-210lb injectors from VS in an nbs intake
-Startup tune done by lsxkilr here in kc metro
Video: Pre-correct pushrod video (only uploading to reflect why I feel that the noise is not isolated):
The noise seems to not be isolated to a single bank, let alone cylinder but I'm out of ideas. Confirmed pushrods with a checker, replaced lifters and head gaskets as well. I have solid oil and fuel pressure at idle. Last thing I could think of to check would be exhaust leaks but would they cause this? Maybe knock sensors? They're new too iirc. Engine bay will be cleaned/cleaned up once it runs right/before it goes to finish out the tune. Thanks
Setup:
-fresh un-ran (except idling while troubleshooting) gen 3 factory 6.0 with factory gen 4 internals, balanced before assembly with ws6store rebuild kit for bearings (including cam) and gaskets
-ss2 cam bought new as 1840-p cam
-Stock ls7 lifters from frankenstein (2 sets. Swapped set 1 thinking that was the issue)
-7.450 pushrods (now, after figuring out how to use the checker)
-PAC 1905 springs
-Stock 317s (got them used, no reason to think they've been modified) with trunnion bushing upgrades
-Ls9 gaskets (previously stock. Changed when I replaced lifters)
-210lb injectors from VS in an nbs intake
-Startup tune done by lsxkilr here in kc metro
Video:
The noise seems to not be isolated to a single bank, let alone cylinder but I'm out of ideas. Confirmed pushrods with a checker, replaced lifters and head gaskets as well. I have solid oil and fuel pressure at idle. Last thing I could think of to check would be exhaust leaks but would they cause this? Maybe knock sensors? They're new too iirc. Engine bay will be cleaned/cleaned up once it runs right/before it goes to finish out the tune. Thanks
Last edited by CBIII; 09-15-2021 at 02:59 PM.
09-15-2021, 04:24 PM
#6
Got it!
Those springs are stout.
My guess is the LS7 lifters just leak too fast for those springs.
A slow leak lifter like the Johnson 2110 may be in order.
Hope others chime in.
I had very similar springs with the 225 lifters and they were loud.
Ron
Those springs are stout.
My guess is the LS7 lifters just leak too fast for those springs.
A slow leak lifter like the Johnson 2110 may be in order.
Hope others chime in.
I had very similar springs with the 225 lifters and they were loud.
Ron
09-16-2021, 08:09 AM
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Those Johnson lifters aren't in the cards at the moment if I do go that route, it wont' be for a while. It seems Morels are the go-to for a beefier-than-stock drop-in lifter in my limited research, but those alone have so many variants I'm not sure what my best bet would be.
I do know the trunnion bushing upgraded rockers are much more difficult to move than OEM ones.. I wonder if their rigidity is causing the pushrods to bottom out in the lifter, simulating junk lifters as well. Immediate steps are to toss stockers back on it and see how it sounds, recheck pushrod length and then start lifter shopping if those all check out.
Also, thanks for the responses!
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09-16-2021, 10:40 PM
#8
I've ran the same set of ls7 lifters for 5 years with btr ".660 dual springs with no noticeable noise. Also in 2 different engines lol
which trunnion kit did you use? I always get the roller bearing style and they turn nice and smooth. Prob smoother than a stock rocker.
sorry I am no real help, just sharing my experiences.
which trunnion kit did you use? I always get the roller bearing style and they turn nice and smooth. Prob smoother than a stock rocker.
sorry I am no real help, just sharing my experiences.
09-17-2021, 08:55 AM
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I've ran the same set of ls7 lifters for 5 years with btr ".660 dual springs with no noticeable noise. Also in 2 different engines lol
which trunnion kit did you use? I always get the roller bearing style and they turn nice and smooth. Prob smoother than a stock rocker.
sorry I am no real help, just sharing my experiences.
which trunnion kit did you use? I always get the roller bearing style and they turn nice and smooth. Prob smoother than a stock rocker.
sorry I am no real help, just sharing my experiences.
Smith Bros. bronze bushing. Given that they felt much harder to move by hand after assembly than the stockers, I'm wondering if they're not moving fully and causing the pushrod to bottom out in the lifter. As my truck is at a buddy's place currently I've got to wait on his availability to run up and test but the current plan is swap back to stock rockers and check, if not that, may be buying a 3rd set of lifters (Prob Morels). I'm desperately hoping it's the rockers.