C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

noisy rockers normal

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Old Jan 21, 2011 | 02:51 AM
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From: Victoria
Default noisy rockers normal

Following recent cam install,new lifters and the fitting of new comp self align roller tips,its really rattly under the tappet covers,lot more noticeable than previously.
Is this normal?
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Old Jan 21, 2011 | 03:05 AM
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Youll hear more noise with roller rockers, cam profile has a little to do with it too. Sewing machine type noise?
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Old Jan 21, 2011 | 08:00 AM
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Yeah. Best explanation I can give is their may be less control over the cam nose than before. What's the cam/spring combo?

If you replaced exhaust gaskets, that can also cause noise -- if not properly sealed.
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Old Jan 21, 2011 | 08:44 AM
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Might weant to just double check bolts and nuts.
They sometimes have a tendency to become a little loose as things settle in.
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Old Jan 21, 2011 | 08:51 AM
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When my motor was new there wasn't as much noise as there is now and I believe with my motor the parts wearing in is causing some of the noise..I adjusted the rockers but the clatter is still there. Its not real loud but like mentioned above it sounds like a loud sewing machine..WW

Last edited by WW7; Jan 21, 2011 at 08:54 AM.
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Old Jan 21, 2011 | 10:17 AM
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Might want to pop the valve covers off and make sure the rockers aren't contacting the underside of the covers. I know my Crane rockers made some contact in the past and the covers needed to be clearanced. Never hurts to check.
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Old Jan 21, 2011 | 10:49 AM
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Originally Posted by Qiken
Following recent cam install,new lifters and the fitting of new comp self align roller tips,its really rattly under the tappet covers,lot more noticeable than previously.
Is this normal?
Even with the correct geometry & preload it is normal to have a little more noise than with the "stock" rockers in place. As mentioned it is a really good idea to pull the covers and check the valve related components for obvious visual issues after the first 500 to 1000 miles of use/break in. Experimenting with a bit more +/- preload may prove to make things quieter under the hood. If you had a significant issue your rocker "noise" will show up as excessive "knock" counts on/in the ECM/PCM when the engine is pushed hard.

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Old Jan 23, 2011 | 05:35 AM
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Originally Posted by cuisinartvette
Youll hear more noise with roller rockers, cam profile has a little to do with it too. Sewing machine type noise?
Yes that is like the sound,I fitted a zz4 cam with lt4(hotcam)springs.
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Old Jan 23, 2011 | 05:38 AM
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Originally Posted by engle1147
Even with the correct geometry & preload it is normal to have a little more noise than with the "stock" rockers in place. As mentioned it is a really good idea to pull the covers and check the valve related components for obvious visual issues after the first 500 to 1000 miles of use/break in. Experimenting with a bit more +/- preload may prove to make things quieter under the hood. If you had a significant issue your rocker "noise" will show up as excessive "knock" counts on/in the ECM/PCM when the engine is pushed hard.

Thanks will pull the covers soon(pain in the A doing this with A/C fitted)
Got to learn how to use this tech one I purchase
,Is knock counts related to poor fuel as well?
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