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Old May 21, 2014 | 10:38 PM
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Default Tapping motor

Hello all,


I'm at my wit's end. Pulled my heads and replaced my lifers with LS7 lifters...nothing. The tapping continues. The tapping frequency traces the rpms (gets faster as the rpms go up). My rocker arms are adjusted. The strange thing is, I feel the tapping pulsating in my clutch and shifter. The only metal shavings I've found are on my magnetic oil drain plug. None in the bulk of my oil. My oil pressure is good even when driving around. It starts at 45 psi when cold and settles at 35psi when at ops temperature. It doesn't vary very much. I'm at a loss. Is it a spun bearing? Is it rod knock? Im at a loss.

HEEEELLLLPPP!!!!!

2007 Corvette LS2

My mods are:

SLP Blackwing intake
SLP Full exhaust
Nick Wilson 102mm Throttle Body
Fast LSXR Intake Manifold
Trickflow 235cc Heads
Harland Sharp 1.8 rocker arms
trick flow 7.400 pushrods
LS7 lifter (brand new)
Cam...Unknown

Last edited by Rafman60; May 21, 2014 at 10:46 PM. Reason: update
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Old May 21, 2014 | 10:50 PM
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that sounds horrible. with the pulsating clutch my bet is the bottom end.
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Old May 21, 2014 | 11:14 PM
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lol...yup. It sounds pretty bad. My bottom end huh? Im gonna pull my oil pan in a week or so. Try to figure this thing out. Any ideas what to look for?
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Old May 21, 2014 | 11:38 PM
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Its your bottom end bearings or crank might be on its way hey you never know, you seem that you could handle taking the oil pan down and looking also easy way is get am oil analysis done while the car is down.. But dont drive it anymore save the engine... I would also suspect the cam.. Can you pull the lifters and take a look at them also. Start from drain oil. Then pull oil pan inspect turn crank. Then pull heads and check lifters and valves.. Just my opinion I guarantee you will find the problem...

Last edited by RamAir972003; May 21, 2014 at 11:42 PM.
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Old May 22, 2014 | 08:00 AM
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Push rod length? Might check the preload on the push rods. Does it make that noise from start up or only after warming up?
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Old May 22, 2014 | 08:57 AM
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Originally Posted by orange rush
Push rod length? Might check the preload on the push rods. Does it make that noise from start up or only after warming up?
Its does it from start up. What's crazy is that the car drives normally. It idles just fine.other than that noise, the car seems okay. I looked at the push rod length earlier. I didn't use a push rod length checker, but I did check it using the torques specs of the rocker bolt. I think ot was between 1.25 To 1.75 turns to 22 tq/lbs.

What does a loose timing chain sound like?
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Old May 22, 2014 | 09:33 AM
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Did those rockers come with valve cover spacers? Pull your valve covers and see if the rockers are touching the silver baffle on the inside of the valve covers.

I know the Yella Terra's need additional space for the 1.8 ratio to clear. And it sounds like every rotation something is hitting. When I've heard rods or mains go they are a lower tone (yes, its hard to tell by the video) but this sounds like its on the top end for sure.

Last edited by C5kid; May 22, 2014 at 09:43 AM.
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Old May 22, 2014 | 09:50 AM
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Originally Posted by C5kid
Did those rockers come with valve cover spacers? Pull your valve covers and see if the rockers are touching the silver baffle on the inside of the valve covers.

I know the Yella Terra's need additional space for the 1.8 ratio to clear. And it sounds like every rotation something is hitting. When I've heard rods or mains go they are a lower tone (yes, its hard to tell by the video) but this sounds like its on the top end for sure.
i agree but the pulsating clutch screams bottom end...maybe rod or thrust bearing.
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Old May 22, 2014 | 03:02 PM
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Sure does have a tinny sound, not like a deep solid knock one might hear from a bearing problem. I'd start by looking at the possible interference of rocker to valve cover as mentioned above.
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Old May 23, 2014 | 04:58 AM
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Pulled the valve covers...doesn't look like the rocker arms are hitting the covers. I'm gonna look at the push rod length again. Maybe I preloaded the lifters wrong.
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Old May 23, 2014 | 08:18 AM
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I wouldn't run that anymore until you find the cause. If that is the death rattle you are only causing more damage.
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Old May 23, 2014 | 08:23 AM
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Originally Posted by orange rush
Push rod length? Might check the preload on the push rods. Does it make that noise from start up or only after warming up?
the noise sounds high up like the push rods are too short, just my .02
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Old May 23, 2014 | 12:38 PM
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Originally Posted by C5kid
Did those rockers come with valve cover spacers? Pull your valve covers and see if the rockers are touching the silver baffle on the inside of the valve covers.

I know the Yella Terra's need additional space for the 1.8 ratio to clear. And it sounds like every rotation something is hitting. When I've heard rods or mains go they are a lower tone (yes, its hard to tell by the video) but this sounds like its on the top end for sure.
I would check this very carefully before going further. When I put comp ultra 1.82s on mine they were hitting and sounded similar to that. The best fix is Yella Terra thicker valve cover gaskets if they touch.
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Old May 24, 2014 | 12:37 AM
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Noise is too fast for rod or bearing noise. Rod knock at idle is slower, deeper, louder and would occur on the power stroke of the affected cylinder which is every other revolution. Your tapping noise sounds more like it is in the top end. Almost sounds like a bunch of things aren't adjusted correctly so there is a lot of slop.

Bill
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Old May 24, 2014 | 06:23 PM
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Okay...I will take another look at my rocker arm adjustment and buy valve cover spacers. Can anyone give me a good idea on how to look at my push rod length? Aparently, I'm doing it wrong. Lol.
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Old May 24, 2014 | 07:12 PM
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You may already know this, but removing the oil pan is a major job in itself. Hope its not as serious as it sounds. Keep us informed.
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Old May 24, 2014 | 07:21 PM
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Originally Posted by Red08
You may already know this, but removing the oil pan is a major job in itself. Hope its not as serious as it sounds. Keep us informed.
Yea I know...I'm hoping I can just undo the motor mounts and raise the motor 3/4s of an inch or so to get clearance. If not, then I will have to go through a days worth of *** pain.
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Old May 24, 2014 | 07:25 PM
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Originally Posted by Rafman60
Yea I know...I'm hoping I can just undo the motor mounts and raise the motor 3/4s of an inch or so to get clearance. If not, then I will have to go through a days worth of *** pain.
Oh, if it were only that easy. Unfortunately it's about a 5 hour job involving the dropping of the cradle and supporting the engine with either a hoist or support brace that most dealerships use.
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Old May 24, 2014 | 07:30 PM
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Originally Posted by subfloor@centurytrans
Oh, if it were only that easy. Unfortunately it's about a 5 hour job involving the dropping of the cradle and supporting the engine with either a hoist or support brace that most dealerships use.
Damn...maybe I should just sell the vette and buy a honda fit. Hahaha
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Old May 24, 2014 | 07:39 PM
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Originally Posted by Rafman60
Damn...maybe I should just sell the vette and buy a honda fit. Hahaha
I put together pretty detailed instructions if you decide to do it yourself. PM me and I'll send them.
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