LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

knock when cold

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Old Oct 10, 2008 | 12:13 AM
  #1  
red 95 z28 lt1's Avatar
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From: long island N.Y.
knock when cold

hey guys i just discovered a big problem

monday i drop my car off to the trans shop to have them replace the lockup solenoid, fix the spedo sensor seal, and do a fluid and filter change, told them to go over the car and make sure everything looks good under there, get my car back tuesday night, all is well, lockup now works and the car downshifts properly, got on it a few times on the way home, no noticeable problems when i put it in the garage.

yesterday i went to start it up to take it out of the garage and i noticed a deep banging or knocking sound, its not consistent and does not have a pattern, its compleatly random. shut it down checked oil, looked good was down a quart, added some oil, started it up and same thing. put my hand on the intake and when ever it knocked i felt it on the engine. pulled it out of the garage and gave it a few light revs and it slowed down and eventually went away in less then a minute. pulled drivers side valve cover and everything looked good. called it quits for the night

tonight i started it up again and same thing, inconsistent knock no pattern, (has no repitition like a lifter or loose rocker arm) as it warmed up it slowed down and went away but i dident let it fully warm up, oil looked good and have aprox 60 psi cold idle, running 15w 50 synthetic, what should i be using, it is a motor that was built with loose bearing tolerences

im hoping its converter bolts or a bad flexplate (which is an sfi approved one)ill try and get a video up this weekend
Old Oct 10, 2008 | 09:51 PM
  #2  
whyrun's Avatar
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From: Abingdon,VA
Sounds like the trans shop took it for a high rpm spin around the block ...lol
Old Oct 11, 2008 | 10:31 AM
  #3  
red 95 z28 lt1's Avatar
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really? because i took it for a spin too after and it seemed fine, doesent make sense, i drove the car last night and everything was good, it seems to be coming from the top of the motor, could not hear it on the bottom end, possible lifter problem
Old Oct 11, 2008 | 03:17 PM
  #4  
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I'd check ur valve adjustment. but i agree sounds like it was taken for a hard drive around town.
Old Oct 11, 2008 | 04:07 PM
  #5  
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Originally Posted by LaredoZ28
I'd check ur valve adjustment. but i agree sounds like it was taken for a hard drive around town.
That is my thoughts, another fine reason to have the work done at your place.
Old Oct 11, 2008 | 04:07 PM
  #6  
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From: Erie PA
hey see if they wrote your mileage down before they did the work and figure out how many miles from there to your house then maybe you can tell if it was drivin around or not.
Old Oct 12, 2008 | 09:32 AM
  #7  
red 95 z28 lt1's Avatar
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i did record the mileage it was 1 mile they drove it, they had to make sure lockup was working, i also only notice it up top on the engine i cant really hear it on the bottom end, im gonna pull the valve covers and start it to see if something is not moving properly
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