Engine knock
05-17-2010, 08:51 AM
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Engine knock Has anyone on here had any valvetrain problems, bent push rod, etc? I drove three hours yesterday to an autocross event, ran one lap not pushing the car very hard and it started to knock. I just had the oil changed with synthentic. The knock seems to come from the back side of the motor. The funny thing is that it won't knock immediately when I start the motor, it takes a few seconds, then when I shut the motor off I hear a puffing sound. I was able to get it home by driving slowly, it seems to go away once I'm in 3rd and DOD kicks in. If I stay below 2000 RPM it's not too loud but anything over 2000 and it sounds pretty bad. It's going to the shop today so I have my fingers crossed. BTW, 72,000 miles on the car.
05-17-2010, 06:23 PM
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So I started the car after work to take it down to the shop. It had sat for about 24 hours. The knock was gone. I held it close to 3k rpm and not a sound. After driving it for about 5 minutes the knock came back. If it was a valve train issue wouldn't it knock even worse at startup? Could it be the torque converter?
Last edited by IAGXP; 05-18-2010 at 08:08 AM. Reason: typo
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05-17-2010, 06:26 PM
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So I started the car after work to take it down to the shop. It had sat for about 24 hours. The knock was gone. I held it close to 3k rpm and not a sound. After driving it for about 5 minutes the knock came back. If it was a drive train issue wouldn't it knock even worse at startup? Could it be the torque converter?
05-17-2010, 09:11 PM
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Very weired. I get some serious valve chatter in the mornings and my trans makes a rattling noise in 3rd and 4th in DOD mode when the trans is cold. I have also have some exhaust leaks so my car sounds like a pile of ****. Drives smooth as glass though... and once it warms up, I can't hear much of anything except for the header whistle. I would recommend changing your oil and filter. maybe add some 10/30w or 20/50. You also might want to do a complete tune up. My Buddy's 6.0 Silverado was running rough at 60K so he bought new plugs. I thought waste of money till he pulled one out. The gap was at 065" and stock calls for .040" also they were very white and the electrode was worn. He put in the new plugs and wires and it runs so much more smoother now.
05-17-2010, 09:18 PM
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Very weired. I get some serious valve chatter in the mornings and my trans makes a rattling noise in 3rd and 4th in DOD mode when the trans is cold. I have also have some exhaust leaks so my car sounds like a pile of ****. Drives smooth as glass though... and once it warms up, I can't hear much of anything except for the header whistle. I would recommend changing your oil and filter. maybe add some 10/30w or 20/50. You also might want to do a complete tune up. My Buddy's 6.0 Silverado was running rough at 60K so he bought new plugs. I thought waste of money till he pulled one out. The gap was at 065" and stock calls for .040" also they were very white and the electrode was worn. He put in the new plugs and wires and it runs so much more smoother now.
05-17-2010, 09:22 PM
#14
Welcome to the world of LS based motors...lmao
I have a oil leak coming from somewhere. Just enough to smudge up the oil pan. Someone pointed it out the other day and my response was, "So? It's a Small Block Chevy...it's what it does."
I have a oil leak coming from somewhere. Just enough to smudge up the oil pan. Someone pointed it out the other day and my response was, "So? It's a Small Block Chevy...it's what it does."
05-17-2010, 09:40 PM
#15
A friend of mine had an SS Camaro with 17,000 miles on it, and he had been running conventional oil since it was new. When he decided to switch over to synthetic the valves got noisy, so he drove it for a few miles and it was still noisy. Changed the oil back to conventional and the noise went away. No problems since. I would try switching back to the regular oil first.
05-17-2010, 10:24 PM
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Has anyone on here had any valvetrain problems, bent push rod, etc? I drove three hours yesterday to an autocross event, ran one lap not pushing the car very hard and it started to knock. I just had the oil changed with synthentic. The knock seems to come from the back side of the motor. The funny thing is that it won't knock immediately when I start the motor, it takes a few seconds, then when I shut the motor off I hear a puffing sound. I was able to get it home by driving slowly, it seems to go away once I'm in 3rd and DOD kicks in. If I stay below 2000 RPM it's not too loud but anything over 2000 and it sounds pretty bad. It's going to the shop today so I have my fingers crossed. BTW, 72,000 miles on the car.
A bottom end knock is pretty loud with a basso vibration that goes straight to the heart. A valvetrain tick is not as loud and doesn't give the basso effect like a bottom end knock.
05-18-2010, 08:53 AM
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rod bearing. probably got starved during cornering at your event. does it do fine when the metal is cool and slightly less expanded and start becoming more audible after the it warms slightly, increases rythmically at higher RPM? I would bet you are looking at a bottom end rebuild.