Sudden loud engine noise!!!, Help me diagnose.. but be gentle! |
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Sudden loud engine noise!!!, Help me diagnose.. but be gentle! |
bondo |
Dec 3 2005, 07:27 PM
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#1
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Practicing my perpendicular parking Group: Members Posts: 4,277 Joined: 19-April 03 From: Los Osos, CA Member No.: 587 Region Association: Central California |
Ok, I've got a 914, with an unknown engine (serial is for RoW 1.7) that was rebuilt "several years ago". Just now I was shuffling cars... started it up, backed it down the driveway. I let it warm up for a couple minutes and shut it off. Then I went to move the MG so I would have toom to park the 914 next to it. The 914 was off for maybe 5 minutes. When I went to start up the 914, it immediately had a loud clack/knock. I drove it up the driveway and parked it next to the MG, and it made the noise the whole way. (about 75 feet) I shut it off, went to get the camera to record some videos. Then I started it up, and recorded these videos:
First is idling at about 1400 RPM, for 30 seconds. Second is idling with a few blips of the throttle, also for 30 seconds. The videos are 2.7 megs each. Thanks! |
bottomend |
Dec 5 2005, 12:29 AM
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#2
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Member Group: Members Posts: 180 Joined: 27-August 05 From: LA,Ca Member No.: 4,683 |
The sound appears to be in unison with the exhaust cadence. The frequency also rises with the throttle being opened. It drops as the throtle is closed. The sound does not appears to be eminating from the center of the engine. I can clearly determin the rotational sound of the crank as well as the pulseing of the exhaust.
My only aural experience with T4 engines was with my bus engine that was soon to drop a valve seat. that sounded like there was little pebbles int he cylinder being shaken. I'm rebuilding a friends engine at the moment and he had a spun bearing. The sound was like a sledge hammer on an anvil. A very strong guy swinging a very big hammer very fast!. Definatly pop the valve covers and look for weird stuff out of place. If you dont see anything, then you've bassically commited to tearing down the block. You should post these files over on the Samba baywindow forum. There are a few guys ( "amskeptic" for example) over there who've been diagnosing the T4 engine for a very long time and they could' probably help. Dont worry about it being a 914.. Just tell 'em that bottomend sent cha! |
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