ready to sell the damn thing
02-02-2006, 08:46 PM
#1
Teching In
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ready to sell the damn thing Ok I have a 98 trans am a4, and their was a tapping underneath the valve cover. You could pinpoint it to the number 1 or 3 cylinders. To start with, the mechanic told me it was probably a bent pushrod, which i knew they were weak in the ls1. Well we replaced the pushrods and rocker arms with comp cams 1.8 ratio rockers and chromoly pushrods. That didn't fix it, So I had it put on a diagnostics machine and the guy said it was a weak lifter! So I had comp cam lifters and new valve springs while we were at it. I figured it has 70k on it so why not. That didn't fix it either. So at this point I am ready to drive it off a cliff. Everyone says it sounds just like a bad lifter, but thats obviously not it. The guy I'm having work on it now says the only thing it could probably be is a flat lobe on the cam, but you can hear it so good. It sounds like its just right underneath the valve cover. If anyone has any suggestions I'm open to them. thanks
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02-02-2006, 11:37 PM
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my car did that and I had a bad rod bearing. That is after I tore apart the whole motor. Mine only started doing it at high rpm or when there was stress on the motor. good luck. I feel your pain and know how the wife thing goes
02-03-2006, 04:13 AM
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You know i had a similar noise to what you explain listen to this vid. and see if it's the same kinda noise
http://www.ezarchive.com/89tang/Albu...49281/99ta.mpg
Bought the car, and took it back to the place of purchase cause of that noise you can here at 2000-3000rpm they said a bad rocker/pushrod so they changed them still no difference thought it was a weak lifter. I didn't worry much about it cause oil pressure was great actually better then i would think with 90k on the clock. So i decided wth i'm thinking of modding it i'll swap the cams and lifters. I get everything down to the shortblock and i noticed the the guy that owned the car before we did must have gotten rid of the car cause of this noise cause the drivers head where the noise was coming from had been taken off. Everything was new on that side gaskets, lifters, pushrods. I pulled the cam and found a spot on the cam that was pitted an chewed up i'd post pic's but the site went down so that link above might not work for awhile. I'll post some pic's too when the site comes back up.
http://www.ezarchive.com/89tang/Albu...49281/99ta.mpg
Bought the car, and took it back to the place of purchase cause of that noise you can here at 2000-3000rpm they said a bad rocker/pushrod so they changed them still no difference thought it was a weak lifter. I didn't worry much about it cause oil pressure was great actually better then i would think with 90k on the clock. So i decided wth i'm thinking of modding it i'll swap the cams and lifters. I get everything down to the shortblock and i noticed the the guy that owned the car before we did must have gotten rid of the car cause of this noise cause the drivers head where the noise was coming from had been taken off. Everything was new on that side gaskets, lifters, pushrods. I pulled the cam and found a spot on the cam that was pitted an chewed up i'd post pic's but the site went down so that link above might not work for awhile. I'll post some pic's too when the site comes back up.