06-10-2017, 07:04 AM | #21 |
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Join Date: May 2010
Posts: 4,179
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Re: Knocking Noise
Sounds like Monday morning you will hear that as a "minimum", you will need to provide new Babbitt.
Might add: One possibility that could have been worse: Say nothing ..... do nothing ..... keep driving ..... throw a connecting rod which penetrates one side of your cast iron block. Last edited by H. L. Chauvin; 06-10-2017 at 07:15 AM. Reason: added note |
06-10-2017, 09:42 AM | #22 |
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Join Date: Apr 2011
Location: Davenport, Iowa
Posts: 2,111
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Re: Knocking Noise
Yup - George nailed it. Chunks of aluminum (actually, Babbitt) on the bottom of the pan or dipper tray invariably means a rod or main bearing has lost its Babbitt. It sounds as though in your case it's the center main, the one that normally goes first due to the crankshaft's whipping action. Shorting #2 and #3 as George suggested will confirm this. I would have also shorted each one individually, though, to eliminate a rod bearing in #2 or #3. The Babbitt chunks may look shiny like aluminum or be a dull gray, all depending upon the Babbitt's composition. I rather doubt that the pieces are aluminum, which if true would cast suspicion upon a damaged piston skirt. But a damaged piston's noise would not go away after 20-30 seconds, as you are experiencing. A center main's knocking might be reduced in this amount of time, but it won't go away on its own. In all likelihood, you have lost the Babbitt in the center main = re-pour time. 'Sorry.
Marshall |
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06-12-2017, 09:25 AM | #23 |
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Join Date: Jun 2013
Location: Pittsburgh Pa
Posts: 279
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Re: Knocking Noise
Not to hijack the original post but I got the exact same symptoms. 20 to 30 seconds knock goes away. Tried George Miller's suggestion of shorting out cylinders two and three to confirm a bearing problem. In fact, I shorted out all four one at a time. Result is no change in knocking sound. Question is, do I drop the pan looking for pieces of Babbitt.....if none found, do I plasti gauge the mains and rods? Any suggestions would be greatly appreciated.
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06-12-2017, 11:29 AM | #24 | |
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Join Date: May 2010
Location: Oregon
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Re: Knocking Noise
Quote:
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09-23-2017, 10:00 AM | #25 |
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Join Date: Apr 2015
Location: Leesburg, Fl.
Posts: 23
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Re: Knocking Noise
Knocking Noise Update, complete engine rebuild done by Doug McPherson in Vero Beach. Boy does she sound different. I'm picking up today from mechanic. Babbitt worn slap out in all caps, cracked block and high compression head, bored 80 over with sleeves and one sleeve dropped down and something with valves.
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09-23-2017, 10:38 PM | #26 |
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Join Date: Dec 2014
Location: Alaska
Posts: 94
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Re: Knocking Noise
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