LS1 knock and rattle

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Jul 26, 2010 | 04:35 PM

jdhedman

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From: Lake in the Hills IL

LS1 knock and rattle

So it all started after this
http://www.youtube.com/watch?v=hfxPf8GcLac

just happened to get it on tape. brought it to maybe 6300 rpm witch is not unusual

started with just a rattle around 2k rpm
http://www.youtube.com/watch?v=-OmY69-Awmk

after check a handful of things I brought it to a local shop and they said "their best guess was a stretched rod bolt" but it was hard to tell if the sound was coming from the very back of the motor or the bell housing. that was $150 wasted

swapped in some arp rod bolts and sound is still there. drove it maybe 30 miles trying to figure some things out and in between checking/ replacing things and now it has a knock at idle.
http://www.youtube.com/watch?v=IyBcNjy-P-s

http://www.youtube.com/watch?v=Fgft7_NU8-o

so far I have had taken off/out.

coil packs - good
plugs - good
wires - new msd 8.5mm
valve covers - good
rockers - good
pushrods - good
heads - good - new gaskets
lifters - seem good
intake - good - new gaskets
trans - good - found out it is built by dr. evil
clutch disk - good - found out its a ls7
pressure plate - good - found out its a ls7
flywheel - resurfaced - found out its a ls7
k member - need to replace with tubular but - good
sway bar links - new polly - broke taking them off
rack and pinion - good
oil pan - good - new gasket
rod bolts - new arp wave loc
headers - new gaskets
oil - clean and free of metal

If I can figure something out today tomorrow it goes into the dealer so they can tell me what it is.

any Ideas?

Jul 26, 2010 | 05:54 PM

Blackhawk777

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From: Omahaish. Nebraska.

As far as the cold start knock, it sounds a lot like the typical piston slap. The rattle/tick you have under load might be a lifter. It may look ok, but could be on the way out. I'm assuming since you checked the rocker arms, you also checked the valve springs? You might have a broken one if you didn't, or some possible valve float? Purely guesses, but that's the best I can tell you.

Jul 26, 2010 | 07:16 PM

jdhedman

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From: Lake in the Hills IL

Thanks for the Ideas. the more the better

Jul 27, 2010 | 10:20 PM

jdhedman

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From: Lake in the Hills IL

The dealer couldn't/wouldn't tell me what it was other than ( a knock from the bottom end) they said none of their techs would dig into it due to it being heavily modified W/E they didn't get paid. So I am now Fairly certain it is a spun bearing and am going to start the process of pullin the motor, taking it apart and shopping for all of the random bolts and gaskets ect.. should be good times.. Just wish I had the cash to go forged

List of stuff that I can think of as of now

- intake mani gasket
- head bolts
- head gaskets
- lifters ( if they are coming out they might as well upgrade)
- oil pump
- timing chain
- oil pan gasket
- rod bearings
- rod bolts
- header gaskets
- header bolts
- motor mounts ( y not)

and I am sure there is a bunch I am missing
now to find prices

Jul 28, 2010 | 10:13 PM

me6894

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Sounds like lifter tick to me, at least something in the valvetrain. Don't know why you would go tearing the whole motor apart when it could be something rather simple.

Jul 29, 2010 | 09:34 AM

HotSilverBird

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Lifter noise......don't go crazy pulling the engine. If you spun a bearing your oil would look like copper glitter.

Mine does the same thing everytime i beat on it it ticks and taps for a few 100 miles. Cheap gm lifters.

Last edited by HotSilverBird; Jul 29, 2010 at 09:41 AM.