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Old 04-26-2008, 02:29 PM   #1
scejmer
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noise in motor

i have been trying to help a buddy out, small block chevy,from the time you start this truck up to shut it down it has a sort of nock to it, it has been up north many times, wouldnt be afraid to drive it anywhere, it just sounds like sh*t,i have check the overhead setting, hydralic liftters,no metal in pan, no loose rockers,also higher rpm seeems to go away, any thoughts?? thanks scott
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Old 04-26-2008, 04:20 PM   #2
jfortner
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Re: noise in motor

I had a flex plate bolt back out that created a knock any time the motor was running. Seemed to go away at higher RPM but not sure why?

John
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Old 04-26-2008, 07:25 PM   #3
28buick
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Re: noise in motor

Don't rule out an exhaust leak at the manifold. They will very often sound like a wrist pin knock or valve train noise.
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Old 04-27-2008, 06:45 AM   #4
bigbadchev72
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Re: noise in motor

my bet is broken flexplate
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1972 k/5 blazer CST 4X4 Crate 350, th350/205, dana44with trac-loc/14 bolt with detroit locker, 4 wheel discs 4.56s, 8" suspension lift using 73-87springs, 1" zerorate custom front crossmember, HAD CV drivelines and driveshaft e-brake, full cage, PRP seats, Full autometer gauges, 38x14.5x16 Toyo M/Ts, 16x10 Polished aluminum rockcrusher wheels

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Old 04-28-2008, 05:50 AM   #5
DANTES JIMMY
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Re: noise in motor

a wrist pin will get worse under torque power brake it and see if it gets worse
usually piston slap is noisy at idle and not full out and will last for ever ( i drove one with some skirt noise for 3 years)
could be valve noise ?? is oil pressure good at idle maybe a collapsed lifter
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Old 04-29-2008, 06:26 PM   #6
scejmer
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Re: noise in motor

thanks, i guess i never thouht about the flex plate, but since i just had to replace the trans adapter mount, you never know what the previous owner did with this thing???
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