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11-04-2009, 03:52 AM
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#1 |
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Registered User
Join Date: Sep 2009
Location: ontario, CA
Posts: 86
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a knock.........?
having a slight inconsistent knock from a 350.
dose not have the typical rod knock noise. i was thinking it could be the crank hitting the oil, flex plat bolt lose or it could just be a plain old rod knock. dose not do it when it is at operating temp. only after it cools.dose not do it under exceleration. any ideas on what it could be before i tear into it. thanks a lot jared |
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11-04-2009, 04:15 AM
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#2 |
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BAD BOW-Silverado XST
Join Date: May 2000
Location: Senior Member from Austin, TX
Posts: 6,431
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Re: a knock.........?
Is it a loud knock? Small or large knock?
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11-04-2009, 02:26 PM
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#3 | |
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Registered User
Join Date: Sep 2009
Location: ontario, CA
Posts: 86
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Re: a knock.........?
very small knock
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11-04-2009, 04:00 PM
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#4 |
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Formerly- 1972SuperCheyenne
 
Join Date: Oct 2008
Location: Wake Forest NC
Posts: 5,782
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Re: a knock.........?
Lifters bleeding down while cold?
__________________
--Josh My Build Thread:http://67-72chevytrucks.com/vboard/s...d.php?t=799218 A good crossthread is better than Loctite any day. Life is not about what you have, but who you have to share it with. |
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11-05-2009, 08:54 AM
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#5 |
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Registered User
Join Date: Mar 2009
Location: glen burnie md
Posts: 174
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Re: a knock.........?
Rod knocks get louder when warm when accelerating the motor. Main bearings knock at idle but shut up (generally) if accelerated. Piston slap is usually louder and more like a clatter. If you can shut up the noise by shorting out one plug wire, it's probably that rod or piston. Bad bearings usually make a lot of noise when started cold but get quieter. Flex plate loose should shut up when placed in gear. Maybe it's just something wanting to get in, or get out. Lousy joke. Knock knock. I once swore that a hopped up '55 Chev that a friend of mine had built had a horrible rod knock, and so did the owner. The machinist just laughed and said bring it back. It was an exhaust pipe hitting the frame at idle.
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11-05-2009, 05:40 PM
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#6 |
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Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Re: a knock.........?
Check the fuel pump, if it is about go, the fuel rod tends to create a knock down low in the engine and it sounds a lot like a rod knock.
__________________
Frank |
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11-05-2009, 06:07 PM
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#7 |
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Slots go on anything!
Join Date: May 2003
Location: Richardson, TX
Posts: 5,957
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Re: a knock.........?
Take a look at the flexplate also. I have seen then crack between the bolt holes that hold it to the crank. Makes a loud knocking noise, but temperature generally doesn't affect it, IIRC.
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11-05-2009, 08:01 PM
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#8 |
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Registered User
Join Date: Sep 2009
Location: ontario, CA
Posts: 86
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Re: a knock.........?
ok cool.
thanks guy for your awesome inpuy |
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11-05-2009, 08:07 PM
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#9 |
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Registered User
Join Date: Sep 2009
Location: ontario, CA
Posts: 86
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Re: a knock.........?
would the little spacer cause a small knock between the flex and the crank or it just look like a spacer.
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11-05-2009, 08:18 PM
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#10 |
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Senior Member
Join Date: Apr 2000
Location: Delta,Pa
Posts: 14,948
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Re: a knock.........?
make sure the torque converter bolts are tight. a main knock is a deeper knock. you will usually feel it in your feet and it will go away with rpm and higher oil pressure. is it louder in gear?
__________________
Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member. |
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11-05-2009, 10:02 PM
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#11 | |
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Slots go on anything!
Join Date: May 2003
Location: Richardson, TX
Posts: 5,957
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Re: a knock.........?
Quote:
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