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Discussion Starter · #1 ·
my truck has had this lifter tap sound from the lower end sounds alot like my flywheel however i removed the trans and looked at teh flywheel and it dont seem to have any shiney section like it rubing however it does move a bit front to back when runing i noticed my thought was the flywheel was craked or bent and rubing somthing making the taping noise but with no marks on the flywheel i am clueless now as to what the tap is
any help would be apriciated
 

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Discussion Starter · #3 ·
i thought that may be it also however i have replaced the flywheel and started the motor with trans and conv disconected and still has the tap
next i thought maybe i just nuts and it a slight knock so i pulled one spark plug at a time to see if it quieted down and nothing so then i pulled my belt off and thinking maybe a pully still there i am totally puzzeled it a anoying tap
any other ideas other then what i have tried thust far
 

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well, I dunno if you are aware or not, but the 4.3's timing chain ticks, usually under 2k rpm or something like that. Mine does it... it's a 01.
 

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Discussion Starter · #5 ·
my motor is a 92 however i dont think it the chain it sounds more like it coming from the flywheel the sound i get is like a real bad lifter tap not a knock sound but a tap however it is under 2k that i get it so maybe it just traveling and i cant hear in front cause of the fan
 

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right. it very well could be a bearing or something going out back there, but GM had a recall or some shiznit where they put a nylon piece next to the timing chain so it wouldn't tick. Just re-stating that to let you know it's very legitimate. good luck wit it tho
 

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Discussion Starter · #7 ·
ill have to look a bit closer at that and see if that may be it and the sound just traveling to make me think it from the rear aside from it sounding like if from the rear what you said sounds like it cause it seems to disapate at 2k rpm and at like under about 800 rpm seems to be between about 800 and 2000 rpm so before i tear in to it ill have to check on the timing chain first
thx again for the heads up onn that i didnt have any idea that could be that

much apriciated

Tazman
 

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check your oil filter for metal content and also the end of your drain plug seen brg failure. have you had any internal coolant leaks .(int gskt leak ,head gskt)
water can cause oil not to get into certain places like the plunger in your lifters
 

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Discussion Starter · #9 ·
that was my first thought was a blown head gasket
however i have no water in my oil or vise versa
and my compresion was between 130 and 140 when i did a compresion check
so i think i eliminated that posibility
guy at a local aout parts store here said that my dist may be bent as the sound seems to be coming from the back side anone have that happen before with a bent dist
only thing that makes me think it not that is the fact it doint do it when it cold only when the oil warms up
however when i had my oil changed about a week ago the guy showed me my filter no shavings no disc but verry verry thin almost water thin but wasent water in it just super thin
been runnin 10-30 castrol in it when i had the oil changed i only had ruffly 400 miles on the oil since i installed the motor and wasent that thin when i put it in
but my temp only runing between 180 and 200 so not heating up to thin the oil
has me totally puzzeled

any info would help the timing chain doesent seem to be where im getting the sound seems from the reas as even under the front i cant hear it at all till i get to the back side of the motor
 

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loco hombre
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roadlet_411 said:
right. it very well could be a bearing or something going out back there, but GM had a recall or some shiznit where they put a nylon piece next to the timing chain so it wouldn't tick. Just re-stating that to let you know it's very legitimate. good luck wit it tho
Yep - and that update sucked. The things wear out before long at all and then you're out time, effort, money, and back to square one. Go figure
 

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TAZ- Same problem here and its not any of the rotating assembly or valvetrain, ive torn my entire 92 (Z) TBI apart, mine sounds like its coming from the rear main/convertor area, doesnt seem to hurt anything but its only present underload with my motor.
 

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"factory freak"...
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the timing chain noise is usually on balance shaft equipped engines. being a 92, yours may, or may not have one.

but that noise usually sounds more like a rattling sound, like screws being shaken around in a coffee can, not a tap.

perhaps it is a lifter tapping?
 

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well, i guess the quickest way to determine if your engine has a balance shaft or not, is to see how close the timing cover comes to the top of the block.
on the B.S. engines, it is very close to to the top, on the older non-B.S. engies, the top of the covers were 2-3" farther down.

if you arent sure, you could dig up some pics. of the two to see the difference....

i know the "rattling noise" is very common on B.S. engines, between 1000-2500 rpm, while lifter "tap" is typically more evident at idle...
 

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yeah my 94' Vin Z has the same thing, it goes away at around 1300, and you cant always hear it, usually only when its just been started and its still not warmed up yet.
 

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Crew Cab Sonoma said:
well, i guess the quickest way to determine if your engine has a balance shaft or not, is to see how close the timing cover comes to the top of the block.
on the B.S. engines, it is very close to to the top, on the older non-B.S. engies, the top of the covers were 2-3" farther down.

if you arent sure, you could dig up some pics. of the two to see the difference....

i know the "rattling noise" is very common on B.S. engines, between 1000-2500 rpm, while lifter "tap" is typically more evident at idle...

So the non BS motors look identical to SBC's on the front and the others are closer to the top. Thanks,but the sound is coming from the convertor area, or so it sounds and only happens around 2k rpm im guessing, not sure how to hook up a tach on this one.
 

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DetroitMusc78le said:
So the non BS motors look identical to SBC's on the front and the others are closer to the top. Thanks,but the sound is coming from the convertor area, or so it sounds and only happens around 2k rpm im guessing, not sure how to hook up a tach on this one.
right the non-BS 4.3`s look just like SBC`s on the front of the block.

you should be able to look over your water pump, without removing anything to see which yours is.

and remember, internal engine noises sometimes are hard to pinpoint. they can carry through the engine, and appear to be coming from areas they really arent....
 

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Crew Cab Sonoma said:
right the non-BS 4.3`s look just like SBC`s on the front of the block.

you should be able to look over your water pump, without removing anything to see which yours is.

and remember, internal engine noises sometimes are hard to pinpoint. they can carry through the engine, and appear to be coming from areas they really arent....
Ive never heard this sound with the SBC's I ow/have owned when the timing chain goes bad/slacks up. These 4.3's are essentially a v8 minus two holes,then.

If this is the case, pete jackson will be under the timing cover on this one too.


Where else to look besides the chain? My lower end is fine(borescopes are great) which makes me scratch my head on this, EVERYTHING is tight and in order.

When the hood is open it sounds like its coming from the passenger side of the engine/tranny area.
 

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mine makes a noise in the exact same area, i think its an exhaust leak though, since it usally dose it around medium load and makes a sortof ticking/hissing noise.i think it is the manifold to y-pipe flange.
 

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It would be awesome if we found an answer cause i have the exact same problem. Sounds like a tap from idle to around 2g's only when it is warm. It started for me a few hundred miles after i rebuilt the motor and has gotten progressively worse. It makes my truck sound like crap. I was also thinking lifters but i ripped off a valve cover last weekend and they all seemed fine! It also isnt a perfectly rhythmic tap which had me confused but definitely makes me think that it could be the timing chain instead of something like a lifter tap. I'd like to know more about this gm fix cause i have looked through all the tech bulletins in alldata and none of them say anything about this.
 
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