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HELP! C5 ticking/knocking after engine refresh

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Old 02-21-2018, 09:52 AM
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brenbuchler
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Default HELP! C5 ticking/knocking after engine refresh

I recently found needle bearings on my drain plug from a failed rocker arm bearing. needless to say I dropped the lower pan and pulled the heads to make sure there were not any needle bearings/metal floating around in the heads/drains. While I was in there I replaced lifters (soaked overnight), headgaskets, rocker arm trunions, and measured for pushrod length. ended up going with a 7.350 rod instead of the 7.400 previously installed and used 0.070 lifter preload. The car starts and runs fine with about 45psi oil pressure at idle. The car is making a knocking/ticking noise that sounds like a diesel truck at idle. I let the car get up to operating temp and the noise is still there and increases with rpm and does not seem to change based on temp. I stripped the heads back down to make sure I did not miss anything and have ruled out an exhaust leak at the header. noise sounds like its coming from under the intake more concentrated to the passenger side. Car is cammed and did not have any previous history of a loud valvetrain/ticking/knocking.
Old 02-21-2018, 11:52 AM
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SaberD
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check to make sure you don't have a loose spark plug. also check the plug wires are connected fully and are not faulty. you can check the resistance of the wires with a multimeter. also check to see if the sound is coming from the injectors and that they are fully seated in the intake manifold.
Old 02-21-2018, 03:40 PM
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bigmackloud
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The factory pushrod length is 7.400. What has been changed in the motor to need shorter pushrods? (heads milled, thinner head gasket, etc).
Old 02-21-2018, 03:46 PM
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brenbuchler
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I remeasured to make sure pushrod length was correct since now two sets of rocker arms bearing have failed. I assume the oversized pushrods were beating the snot out of the rockers causing the failures.
Old 02-21-2018, 03:47 PM
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brenbuchler
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Originally Posted by SaberD
check to make sure you don't have a loose spark plug. also check the plug wires are connected fully and are not faulty. you can check the resistance of the wires with a multimeter. also check to see if the sound is coming from the injectors and that they are fully seated in the intake manifold.
i will recheck for a loose spark plug and connection. I just installed new MSD wires so I do not suspect this will be the case.

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