[V8] Noise that is driving me absolutely CRAZY!!

[Ed Kellock]

 Chiming in.... I've had a noise only at idle and when warm since I owned
the car.  I don't know if it's the same noise as I've never though of it
relative to diesel noise, but it could be characterized that way.  It was
unchanged by a timing belt service which included every moving part new for
both timing and serpentine belts.  It seems to be in the passenger side
cylinder head area.  I've always thought lifters or cam chain(s).

Previous to my ownership the car had timing belt failure.  That repair has
always been suspect in my mind because of some of the things I found when I
did my own timing belt service, like mis-timed engine and stipped or missing
bolts, supposedly at a dealer, no less.

In addition, at very low rpm in gear, there is a noticeable pulsation
characteristic to the power delivery, as if one cylinder is significantly
down on power as if due to a leaky/nicked or ill-actuated valve.  I had a
compression and leak-down test done years ago and it was pronounced healthy
but then they didn't improve how it ran either so I'm suspect of that
service as well.  In fact, I don't think anyone but me or my friends have
touched my car mechanically in 5 years.  Anyway, I'm talking about 1000 rpm
in 5th gear trying to gently accelerate as if more out of intertia spurred
by a feathered throttle than any real engine output.  The more throttle you
give it, the more pronounce the pulsation is, until rpm increases and it
becomes unnoticeable.

Given my doubts about the valvetrain, etc. I always figured that the cam
chains or a lifter were the culprit of both the noise and the pulsation,
both of which I've come to ignore.  The car just doesn't seem to care.
Frequent rev-limiter tests and a couple questionable trailer towing events
have not brought about any engine behavior of any concern.

I've always figured that when this engine goes I'll just drop a 4.2 in
there.  In the meantime, full steam ahead, damn the torpedoes!

Ed


-----Original Message-----
> From: v8-bounces at audifans.com [mailto:v8-bounces at audifans.com]On Behalf
> Of kyle leatherwood
> Sent: March 19, 2006 6:25 PM
> To: v8 at audifans.com
> Subject: [V8] Noise that is driving me absolutely CRAZY!!
>
>
> Ok everyone.  I have officially gotten tired of hearing this abnormal
> noise
> that my 91 V8 5 speed makes.  This noise ONLY appears when the engine gets
> to operating temperature. Between startup and operating temp, the engine
> is
> as quiet as a mouse (a tiny bit of lifter tick on occasion).  This noise
> sounds like there is a freaking diesel engine under the hood.  Engine has
> had entire t-belt service done with new bearings and rollers all
> around.  I
> have pulled both valve covers and checked cam chains, they are great.  I
> have pulled off the serp belt to eliminate accessory noise.  Odd thing is
> that Mark Willoughby's 4.2 5 speed makes the exact same noise.  Keith at
> Germanautoconnection says he rebuilt the entire valve train on a 4.2 once
> to
> try and eliminate the noise, but to no avail and told me not to worry
> about
> it.  Car drives beautifully, no loss of power of any kind.  AARRGG.
>
> Anyway, as anal and picky as I am about my vehicles, this noise is driving
> me nuts, so I must find out what is causing it.  My 1990 with 130,000
> miles
> makes no noise whatsoever, and this one only has 116,000 on it.
>
> Has anyone out there run into this and found out what it is??
>
> Any help with finding this out will save my sanity in driving this
> wonderful
> vehicle.
>
> thanks,
>
> Kyle
>
>
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