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LT4 noise normal?

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Old Sep 8, 2018 | 07:17 PM
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Default LT4 noise normal?

Does this sound like a healthy LT4? Seems a little noisy to me but i have no experience with LT4s. Car has 35k miles on it. Engine also has a slight vibration felt around 1200rpm
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Old Sep 8, 2018 | 07:25 PM
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Knock or an exhaust leak?

I can't tell from the video..
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Old Sep 8, 2018 | 07:46 PM
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Exhaust manifold leak. Just dealt with this earlier this year. Fixed it by putting headers on. Kind of surprising at 35k though.
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Old Sep 8, 2018 | 07:55 PM
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Originally Posted by haxxx
Exhaust manifold leak. Just dealt with this earlier this year. Fixed it by putting headers on. Kind of surprising at 35k though.
Thanks. Do LT4s vibrate a bit?
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Old Sep 8, 2018 | 09:09 PM
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Originally Posted by Jitsu
Thanks. Do LT4s vibrate a bit?
If mine does, I've never noticed. So for me, that's "no."
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Old Sep 8, 2018 | 09:44 PM
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Originally Posted by haxxx
Exhaust manifold leak. Just dealt with this earlier this year. Fixed it by putting headers on. Kind of surprising at 35k though.
What brand headers? Long or short tubes?
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Old Sep 8, 2018 | 11:09 PM
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Originally Posted by Jitsu
Thanks. Do LT4s vibrate a bit?
Mine doesn't vibrate. Has your flywheel been changed? If so that might be the problem. Does it vibrate when the car isn't moving when you hold the idle up high? If not and if it only vibrates when its moving then the problem is most likely in the U-joints in the driveshaft or in the half shafts. It could also be from a bad pilot bearing in the back of the crankshaft.
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Old Sep 9, 2018 | 12:08 AM
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You could have a miss, could be lots of things, vacuum leak?
They should idle very smooth. Those manifolds are known to crack , as said headers a great fix.
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Old Sep 9, 2018 | 06:16 AM
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Originally Posted by turbobuick33
What brand headers? Long or short tubes?
I went with short. I wanted the least amount of fitment issues to deal with. Still took me 20 hours over a weekend. Theses headers are great once I worked out how to do the brackets (the directions are useless) and a couple other small issues. If you decide to use them let me know, I can send you some pictures and let you know what kind of issues you will run into.

https://www.rockauto.com/en/moreinfo...041398&jsn=447
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